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2641 lines
71 KiB
2641 lines
71 KiB
/* |
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* blkfront.c |
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* |
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* XenLinux virtual block device driver. |
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* |
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* Copyright (c) 2003-2004, Keir Fraser & Steve Hand |
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* Modifications by Mark A. Williamson are (c) Intel Research Cambridge |
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* Copyright (c) 2004, Christian Limpach |
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* Copyright (c) 2004, Andrew Warfield |
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* Copyright (c) 2005, Christopher Clark |
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* Copyright (c) 2005, XenSource Ltd |
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* |
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* This program is free software; you can redistribute it and/or |
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* modify it under the terms of the GNU General Public License version 2 |
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* as published by the Free Software Foundation; or, when distributed |
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* separately from the Linux kernel or incorporated into other |
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* software packages, subject to the following license: |
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* |
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* Permission is hereby granted, free of charge, to any person obtaining a copy |
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* of this source file (the "Software"), to deal in the Software without |
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* restriction, including without limitation the rights to use, copy, modify, |
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* merge, publish, distribute, sublicense, and/or sell copies of the Software, |
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* and to permit persons to whom the Software is furnished to do so, subject to |
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* the following conditions: |
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* |
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* The above copyright notice and this permission notice shall be included in |
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* all copies or substantial portions of the Software. |
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* |
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE |
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING |
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS |
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* IN THE SOFTWARE. |
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*/ |
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|
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#include <linux/interrupt.h> |
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#include <linux/blkdev.h> |
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#include <linux/blk-mq.h> |
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#include <linux/hdreg.h> |
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#include <linux/cdrom.h> |
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#include <linux/module.h> |
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#include <linux/slab.h> |
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#include <linux/major.h> |
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#include <linux/mutex.h> |
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#include <linux/scatterlist.h> |
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#include <linux/bitmap.h> |
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#include <linux/list.h> |
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#include <linux/workqueue.h> |
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#include <linux/sched/mm.h> |
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|
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#include <xen/xen.h> |
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#include <xen/xenbus.h> |
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#include <xen/grant_table.h> |
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#include <xen/events.h> |
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#include <xen/page.h> |
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#include <xen/platform_pci.h> |
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|
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#include <xen/interface/grant_table.h> |
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#include <xen/interface/io/blkif.h> |
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#include <xen/interface/io/protocols.h> |
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|
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#include <asm/xen/hypervisor.h> |
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|
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/* |
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* The minimal size of segment supported by the block framework is PAGE_SIZE. |
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* When Linux is using a different page size than Xen, it may not be possible |
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* to put all the data in a single segment. |
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* This can happen when the backend doesn't support indirect descriptor and |
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* therefore the maximum amount of data that a request can carry is |
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* BLKIF_MAX_SEGMENTS_PER_REQUEST * XEN_PAGE_SIZE = 44KB |
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* |
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* Note that we only support one extra request. So the Linux page size |
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* should be <= ( 2 * BLKIF_MAX_SEGMENTS_PER_REQUEST * XEN_PAGE_SIZE) = |
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* 88KB. |
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*/ |
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#define HAS_EXTRA_REQ (BLKIF_MAX_SEGMENTS_PER_REQUEST < XEN_PFN_PER_PAGE) |
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|
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enum blkif_state { |
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BLKIF_STATE_DISCONNECTED, |
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BLKIF_STATE_CONNECTED, |
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BLKIF_STATE_SUSPENDED, |
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BLKIF_STATE_ERROR, |
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}; |
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|
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struct grant { |
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grant_ref_t gref; |
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struct page *page; |
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struct list_head node; |
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}; |
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|
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enum blk_req_status { |
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REQ_PROCESSING, |
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REQ_WAITING, |
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REQ_DONE, |
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REQ_ERROR, |
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REQ_EOPNOTSUPP, |
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}; |
|
|
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struct blk_shadow { |
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struct blkif_request req; |
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struct request *request; |
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struct grant **grants_used; |
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struct grant **indirect_grants; |
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struct scatterlist *sg; |
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unsigned int num_sg; |
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enum blk_req_status status; |
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|
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#define NO_ASSOCIATED_ID ~0UL |
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/* |
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* Id of the sibling if we ever need 2 requests when handling a |
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* block I/O request |
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*/ |
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unsigned long associated_id; |
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}; |
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|
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struct blkif_req { |
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blk_status_t error; |
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}; |
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|
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static inline struct blkif_req *blkif_req(struct request *rq) |
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{ |
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return blk_mq_rq_to_pdu(rq); |
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} |
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|
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static DEFINE_MUTEX(blkfront_mutex); |
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static const struct block_device_operations xlvbd_block_fops; |
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static struct delayed_work blkfront_work; |
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static LIST_HEAD(info_list); |
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|
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/* |
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* Maximum number of segments in indirect requests, the actual value used by |
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* the frontend driver is the minimum of this value and the value provided |
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* by the backend driver. |
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*/ |
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|
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static unsigned int xen_blkif_max_segments = 32; |
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module_param_named(max_indirect_segments, xen_blkif_max_segments, uint, 0444); |
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MODULE_PARM_DESC(max_indirect_segments, |
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"Maximum amount of segments in indirect requests (default is 32)"); |
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|
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static unsigned int xen_blkif_max_queues = 4; |
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module_param_named(max_queues, xen_blkif_max_queues, uint, 0444); |
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MODULE_PARM_DESC(max_queues, "Maximum number of hardware queues/rings used per virtual disk"); |
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|
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/* |
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* Maximum order of pages to be used for the shared ring between front and |
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* backend, 4KB page granularity is used. |
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*/ |
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static unsigned int xen_blkif_max_ring_order; |
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module_param_named(max_ring_page_order, xen_blkif_max_ring_order, int, 0444); |
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MODULE_PARM_DESC(max_ring_page_order, "Maximum order of pages to be used for the shared ring"); |
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|
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#define BLK_RING_SIZE(info) \ |
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__CONST_RING_SIZE(blkif, XEN_PAGE_SIZE * (info)->nr_ring_pages) |
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|
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/* |
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* ring-ref%u i=(-1UL) would take 11 characters + 'ring-ref' is 8, so 19 |
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* characters are enough. Define to 20 to keep consistent with backend. |
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*/ |
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#define RINGREF_NAME_LEN (20) |
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/* |
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* queue-%u would take 7 + 10(UINT_MAX) = 17 characters. |
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*/ |
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#define QUEUE_NAME_LEN (17) |
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|
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/* |
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* Per-ring info. |
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* Every blkfront device can associate with one or more blkfront_ring_info, |
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* depending on how many hardware queues/rings to be used. |
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*/ |
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struct blkfront_ring_info { |
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/* Lock to protect data in every ring buffer. */ |
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spinlock_t ring_lock; |
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struct blkif_front_ring ring; |
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unsigned int ring_ref[XENBUS_MAX_RING_GRANTS]; |
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unsigned int evtchn, irq; |
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struct work_struct work; |
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struct gnttab_free_callback callback; |
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struct list_head indirect_pages; |
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struct list_head grants; |
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unsigned int persistent_gnts_c; |
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unsigned long shadow_free; |
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struct blkfront_info *dev_info; |
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struct blk_shadow shadow[]; |
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}; |
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|
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/* |
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* We have one of these per vbd, whether ide, scsi or 'other'. They |
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* hang in private_data off the gendisk structure. We may end up |
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* putting all kinds of interesting stuff here :-) |
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*/ |
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struct blkfront_info |
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{ |
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struct mutex mutex; |
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struct xenbus_device *xbdev; |
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struct gendisk *gd; |
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u16 sector_size; |
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unsigned int physical_sector_size; |
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unsigned long vdisk_info; |
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int vdevice; |
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blkif_vdev_t handle; |
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enum blkif_state connected; |
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/* Number of pages per ring buffer. */ |
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unsigned int nr_ring_pages; |
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struct request_queue *rq; |
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unsigned int feature_flush:1; |
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unsigned int feature_fua:1; |
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unsigned int feature_discard:1; |
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unsigned int feature_secdiscard:1; |
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unsigned int feature_persistent:1; |
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unsigned int discard_granularity; |
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unsigned int discard_alignment; |
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/* Number of 4KB segments handled */ |
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unsigned int max_indirect_segments; |
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int is_ready; |
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struct blk_mq_tag_set tag_set; |
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struct blkfront_ring_info *rinfo; |
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unsigned int nr_rings; |
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unsigned int rinfo_size; |
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/* Save uncomplete reqs and bios for migration. */ |
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struct list_head requests; |
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struct bio_list bio_list; |
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struct list_head info_list; |
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}; |
|
|
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static unsigned int nr_minors; |
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static unsigned long *minors; |
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static DEFINE_SPINLOCK(minor_lock); |
|
|
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#define GRANT_INVALID_REF 0 |
|
|
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#define PARTS_PER_DISK 16 |
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#define PARTS_PER_EXT_DISK 256 |
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|
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#define BLKIF_MAJOR(dev) ((dev)>>8) |
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#define BLKIF_MINOR(dev) ((dev) & 0xff) |
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|
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#define EXT_SHIFT 28 |
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#define EXTENDED (1<<EXT_SHIFT) |
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#define VDEV_IS_EXTENDED(dev) ((dev)&(EXTENDED)) |
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#define BLKIF_MINOR_EXT(dev) ((dev)&(~EXTENDED)) |
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#define EMULATED_HD_DISK_MINOR_OFFSET (0) |
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#define EMULATED_HD_DISK_NAME_OFFSET (EMULATED_HD_DISK_MINOR_OFFSET / 256) |
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#define EMULATED_SD_DISK_MINOR_OFFSET (0) |
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#define EMULATED_SD_DISK_NAME_OFFSET (EMULATED_SD_DISK_MINOR_OFFSET / 256) |
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|
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#define DEV_NAME "xvd" /* name in /dev */ |
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|
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/* |
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* Grants are always the same size as a Xen page (i.e 4KB). |
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* A physical segment is always the same size as a Linux page. |
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* Number of grants per physical segment |
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*/ |
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#define GRANTS_PER_PSEG (PAGE_SIZE / XEN_PAGE_SIZE) |
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|
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#define GRANTS_PER_INDIRECT_FRAME \ |
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(XEN_PAGE_SIZE / sizeof(struct blkif_request_segment)) |
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|
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#define INDIRECT_GREFS(_grants) \ |
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DIV_ROUND_UP(_grants, GRANTS_PER_INDIRECT_FRAME) |
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|
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static int blkfront_setup_indirect(struct blkfront_ring_info *rinfo); |
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static void blkfront_gather_backend_features(struct blkfront_info *info); |
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static int negotiate_mq(struct blkfront_info *info); |
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|
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#define for_each_rinfo(info, ptr, idx) \ |
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for ((ptr) = (info)->rinfo, (idx) = 0; \ |
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(idx) < (info)->nr_rings; \ |
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(idx)++, (ptr) = (void *)(ptr) + (info)->rinfo_size) |
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|
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static inline struct blkfront_ring_info * |
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get_rinfo(const struct blkfront_info *info, unsigned int i) |
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{ |
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BUG_ON(i >= info->nr_rings); |
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return (void *)info->rinfo + i * info->rinfo_size; |
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} |
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|
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static int get_id_from_freelist(struct blkfront_ring_info *rinfo) |
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{ |
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unsigned long free = rinfo->shadow_free; |
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|
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BUG_ON(free >= BLK_RING_SIZE(rinfo->dev_info)); |
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rinfo->shadow_free = rinfo->shadow[free].req.u.rw.id; |
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rinfo->shadow[free].req.u.rw.id = 0x0fffffee; /* debug */ |
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return free; |
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} |
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|
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static int add_id_to_freelist(struct blkfront_ring_info *rinfo, |
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unsigned long id) |
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{ |
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if (rinfo->shadow[id].req.u.rw.id != id) |
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return -EINVAL; |
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if (rinfo->shadow[id].request == NULL) |
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return -EINVAL; |
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rinfo->shadow[id].req.u.rw.id = rinfo->shadow_free; |
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rinfo->shadow[id].request = NULL; |
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rinfo->shadow_free = id; |
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return 0; |
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} |
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|
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static int fill_grant_buffer(struct blkfront_ring_info *rinfo, int num) |
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{ |
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struct blkfront_info *info = rinfo->dev_info; |
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struct page *granted_page; |
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struct grant *gnt_list_entry, *n; |
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int i = 0; |
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|
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while (i < num) { |
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gnt_list_entry = kzalloc(sizeof(struct grant), GFP_NOIO); |
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if (!gnt_list_entry) |
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goto out_of_memory; |
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|
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if (info->feature_persistent) { |
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granted_page = alloc_page(GFP_NOIO); |
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if (!granted_page) { |
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kfree(gnt_list_entry); |
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goto out_of_memory; |
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} |
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gnt_list_entry->page = granted_page; |
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} |
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|
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gnt_list_entry->gref = GRANT_INVALID_REF; |
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list_add(&gnt_list_entry->node, &rinfo->grants); |
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i++; |
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} |
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|
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return 0; |
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|
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out_of_memory: |
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list_for_each_entry_safe(gnt_list_entry, n, |
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&rinfo->grants, node) { |
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list_del(&gnt_list_entry->node); |
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if (info->feature_persistent) |
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__free_page(gnt_list_entry->page); |
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kfree(gnt_list_entry); |
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i--; |
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} |
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BUG_ON(i != 0); |
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return -ENOMEM; |
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} |
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|
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static struct grant *get_free_grant(struct blkfront_ring_info *rinfo) |
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{ |
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struct grant *gnt_list_entry; |
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|
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BUG_ON(list_empty(&rinfo->grants)); |
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gnt_list_entry = list_first_entry(&rinfo->grants, struct grant, |
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node); |
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list_del(&gnt_list_entry->node); |
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|
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if (gnt_list_entry->gref != GRANT_INVALID_REF) |
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rinfo->persistent_gnts_c--; |
|
|
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return gnt_list_entry; |
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} |
|
|
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static inline void grant_foreign_access(const struct grant *gnt_list_entry, |
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const struct blkfront_info *info) |
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{ |
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gnttab_page_grant_foreign_access_ref_one(gnt_list_entry->gref, |
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info->xbdev->otherend_id, |
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gnt_list_entry->page, |
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0); |
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} |
|
|
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static struct grant *get_grant(grant_ref_t *gref_head, |
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unsigned long gfn, |
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struct blkfront_ring_info *rinfo) |
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{ |
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struct grant *gnt_list_entry = get_free_grant(rinfo); |
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struct blkfront_info *info = rinfo->dev_info; |
|
|
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if (gnt_list_entry->gref != GRANT_INVALID_REF) |
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return gnt_list_entry; |
|
|
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/* Assign a gref to this page */ |
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gnt_list_entry->gref = gnttab_claim_grant_reference(gref_head); |
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BUG_ON(gnt_list_entry->gref == -ENOSPC); |
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if (info->feature_persistent) |
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grant_foreign_access(gnt_list_entry, info); |
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else { |
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/* Grant access to the GFN passed by the caller */ |
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gnttab_grant_foreign_access_ref(gnt_list_entry->gref, |
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info->xbdev->otherend_id, |
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gfn, 0); |
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} |
|
|
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return gnt_list_entry; |
|
} |
|
|
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static struct grant *get_indirect_grant(grant_ref_t *gref_head, |
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struct blkfront_ring_info *rinfo) |
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{ |
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struct grant *gnt_list_entry = get_free_grant(rinfo); |
|
struct blkfront_info *info = rinfo->dev_info; |
|
|
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if (gnt_list_entry->gref != GRANT_INVALID_REF) |
|
return gnt_list_entry; |
|
|
|
/* Assign a gref to this page */ |
|
gnt_list_entry->gref = gnttab_claim_grant_reference(gref_head); |
|
BUG_ON(gnt_list_entry->gref == -ENOSPC); |
|
if (!info->feature_persistent) { |
|
struct page *indirect_page; |
|
|
|
/* Fetch a pre-allocated page to use for indirect grefs */ |
|
BUG_ON(list_empty(&rinfo->indirect_pages)); |
|
indirect_page = list_first_entry(&rinfo->indirect_pages, |
|
struct page, lru); |
|
list_del(&indirect_page->lru); |
|
gnt_list_entry->page = indirect_page; |
|
} |
|
grant_foreign_access(gnt_list_entry, info); |
|
|
|
return gnt_list_entry; |
|
} |
|
|
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static const char *op_name(int op) |
|
{ |
|
static const char *const names[] = { |
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[BLKIF_OP_READ] = "read", |
|
[BLKIF_OP_WRITE] = "write", |
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[BLKIF_OP_WRITE_BARRIER] = "barrier", |
|
[BLKIF_OP_FLUSH_DISKCACHE] = "flush", |
|
[BLKIF_OP_DISCARD] = "discard" }; |
|
|
|
if (op < 0 || op >= ARRAY_SIZE(names)) |
|
return "unknown"; |
|
|
|
if (!names[op]) |
|
return "reserved"; |
|
|
|
return names[op]; |
|
} |
|
static int xlbd_reserve_minors(unsigned int minor, unsigned int nr) |
|
{ |
|
unsigned int end = minor + nr; |
|
int rc; |
|
|
|
if (end > nr_minors) { |
|
unsigned long *bitmap, *old; |
|
|
|
bitmap = kcalloc(BITS_TO_LONGS(end), sizeof(*bitmap), |
|
GFP_KERNEL); |
|
if (bitmap == NULL) |
|
return -ENOMEM; |
|
|
|
spin_lock(&minor_lock); |
|
if (end > nr_minors) { |
|
old = minors; |
|
memcpy(bitmap, minors, |
|
BITS_TO_LONGS(nr_minors) * sizeof(*bitmap)); |
|
minors = bitmap; |
|
nr_minors = BITS_TO_LONGS(end) * BITS_PER_LONG; |
|
} else |
|
old = bitmap; |
|
spin_unlock(&minor_lock); |
|
kfree(old); |
|
} |
|
|
|
spin_lock(&minor_lock); |
|
if (find_next_bit(minors, end, minor) >= end) { |
|
bitmap_set(minors, minor, nr); |
|
rc = 0; |
|
} else |
|
rc = -EBUSY; |
|
spin_unlock(&minor_lock); |
|
|
|
return rc; |
|
} |
|
|
|
static void xlbd_release_minors(unsigned int minor, unsigned int nr) |
|
{ |
|
unsigned int end = minor + nr; |
|
|
|
BUG_ON(end > nr_minors); |
|
spin_lock(&minor_lock); |
|
bitmap_clear(minors, minor, nr); |
|
spin_unlock(&minor_lock); |
|
} |
|
|
|
static void blkif_restart_queue_callback(void *arg) |
|
{ |
|
struct blkfront_ring_info *rinfo = (struct blkfront_ring_info *)arg; |
|
schedule_work(&rinfo->work); |
|
} |
|
|
|
static int blkif_getgeo(struct block_device *bd, struct hd_geometry *hg) |
|
{ |
|
/* We don't have real geometry info, but let's at least return |
|
values consistent with the size of the device */ |
|
sector_t nsect = get_capacity(bd->bd_disk); |
|
sector_t cylinders = nsect; |
|
|
|
hg->heads = 0xff; |
|
hg->sectors = 0x3f; |
|
sector_div(cylinders, hg->heads * hg->sectors); |
|
hg->cylinders = cylinders; |
|
if ((sector_t)(hg->cylinders + 1) * hg->heads * hg->sectors < nsect) |
|
hg->cylinders = 0xffff; |
|
return 0; |
|
} |
|
|
|
static int blkif_ioctl(struct block_device *bdev, fmode_t mode, |
|
unsigned command, unsigned long argument) |
|
{ |
|
struct blkfront_info *info = bdev->bd_disk->private_data; |
|
int i; |
|
|
|
switch (command) { |
|
case CDROMMULTISESSION: |
|
for (i = 0; i < sizeof(struct cdrom_multisession); i++) |
|
if (put_user(0, (char __user *)(argument + i))) |
|
return -EFAULT; |
|
return 0; |
|
case CDROM_GET_CAPABILITY: |
|
if (!(info->vdisk_info & VDISK_CDROM)) |
|
return -EINVAL; |
|
return 0; |
|
default: |
|
return -EINVAL; |
|
} |
|
} |
|
|
|
static unsigned long blkif_ring_get_request(struct blkfront_ring_info *rinfo, |
|
struct request *req, |
|
struct blkif_request **ring_req) |
|
{ |
|
unsigned long id; |
|
|
|
*ring_req = RING_GET_REQUEST(&rinfo->ring, rinfo->ring.req_prod_pvt); |
|
rinfo->ring.req_prod_pvt++; |
|
|
|
id = get_id_from_freelist(rinfo); |
|
rinfo->shadow[id].request = req; |
|
rinfo->shadow[id].status = REQ_PROCESSING; |
|
rinfo->shadow[id].associated_id = NO_ASSOCIATED_ID; |
|
|
|
rinfo->shadow[id].req.u.rw.id = id; |
|
|
|
return id; |
|
} |
|
|
|
static int blkif_queue_discard_req(struct request *req, struct blkfront_ring_info *rinfo) |
|
{ |
|
struct blkfront_info *info = rinfo->dev_info; |
|
struct blkif_request *ring_req, *final_ring_req; |
|
unsigned long id; |
|
|
|
/* Fill out a communications ring structure. */ |
|
id = blkif_ring_get_request(rinfo, req, &final_ring_req); |
|
ring_req = &rinfo->shadow[id].req; |
|
|
|
ring_req->operation = BLKIF_OP_DISCARD; |
|
ring_req->u.discard.nr_sectors = blk_rq_sectors(req); |
|
ring_req->u.discard.id = id; |
|
ring_req->u.discard.sector_number = (blkif_sector_t)blk_rq_pos(req); |
|
if (req_op(req) == REQ_OP_SECURE_ERASE && info->feature_secdiscard) |
|
ring_req->u.discard.flag = BLKIF_DISCARD_SECURE; |
|
else |
|
ring_req->u.discard.flag = 0; |
|
|
|
/* Copy the request to the ring page. */ |
|
*final_ring_req = *ring_req; |
|
rinfo->shadow[id].status = REQ_WAITING; |
|
|
|
return 0; |
|
} |
|
|
|
struct setup_rw_req { |
|
unsigned int grant_idx; |
|
struct blkif_request_segment *segments; |
|
struct blkfront_ring_info *rinfo; |
|
struct blkif_request *ring_req; |
|
grant_ref_t gref_head; |
|
unsigned int id; |
|
/* Only used when persistent grant is used and it's a read request */ |
|
bool need_copy; |
|
unsigned int bvec_off; |
|
char *bvec_data; |
|
|
|
bool require_extra_req; |
|
struct blkif_request *extra_ring_req; |
|
}; |
|
|
|
static void blkif_setup_rw_req_grant(unsigned long gfn, unsigned int offset, |
|
unsigned int len, void *data) |
|
{ |
|
struct setup_rw_req *setup = data; |
|
int n, ref; |
|
struct grant *gnt_list_entry; |
|
unsigned int fsect, lsect; |
|
/* Convenient aliases */ |
|
unsigned int grant_idx = setup->grant_idx; |
|
struct blkif_request *ring_req = setup->ring_req; |
|
struct blkfront_ring_info *rinfo = setup->rinfo; |
|
/* |
|
* We always use the shadow of the first request to store the list |
|
* of grant associated to the block I/O request. This made the |
|
* completion more easy to handle even if the block I/O request is |
|
* split. |
|
*/ |
|
struct blk_shadow *shadow = &rinfo->shadow[setup->id]; |
|
|
|
if (unlikely(setup->require_extra_req && |
|
grant_idx >= BLKIF_MAX_SEGMENTS_PER_REQUEST)) { |
|
/* |
|
* We are using the second request, setup grant_idx |
|
* to be the index of the segment array. |
|
*/ |
|
grant_idx -= BLKIF_MAX_SEGMENTS_PER_REQUEST; |
|
ring_req = setup->extra_ring_req; |
|
} |
|
|
|
if ((ring_req->operation == BLKIF_OP_INDIRECT) && |
|
(grant_idx % GRANTS_PER_INDIRECT_FRAME == 0)) { |
|
if (setup->segments) |
|
kunmap_atomic(setup->segments); |
|
|
|
n = grant_idx / GRANTS_PER_INDIRECT_FRAME; |
|
gnt_list_entry = get_indirect_grant(&setup->gref_head, rinfo); |
|
shadow->indirect_grants[n] = gnt_list_entry; |
|
setup->segments = kmap_atomic(gnt_list_entry->page); |
|
ring_req->u.indirect.indirect_grefs[n] = gnt_list_entry->gref; |
|
} |
|
|
|
gnt_list_entry = get_grant(&setup->gref_head, gfn, rinfo); |
|
ref = gnt_list_entry->gref; |
|
/* |
|
* All the grants are stored in the shadow of the first |
|
* request. Therefore we have to use the global index. |
|
*/ |
|
shadow->grants_used[setup->grant_idx] = gnt_list_entry; |
|
|
|
if (setup->need_copy) { |
|
void *shared_data; |
|
|
|
shared_data = kmap_atomic(gnt_list_entry->page); |
|
/* |
|
* this does not wipe data stored outside the |
|
* range sg->offset..sg->offset+sg->length. |
|
* Therefore, blkback *could* see data from |
|
* previous requests. This is OK as long as |
|
* persistent grants are shared with just one |
|
* domain. It may need refactoring if this |
|
* changes |
|
*/ |
|
memcpy(shared_data + offset, |
|
setup->bvec_data + setup->bvec_off, |
|
len); |
|
|
|
kunmap_atomic(shared_data); |
|
setup->bvec_off += len; |
|
} |
|
|
|
fsect = offset >> 9; |
|
lsect = fsect + (len >> 9) - 1; |
|
if (ring_req->operation != BLKIF_OP_INDIRECT) { |
|
ring_req->u.rw.seg[grant_idx] = |
|
(struct blkif_request_segment) { |
|
.gref = ref, |
|
.first_sect = fsect, |
|
.last_sect = lsect }; |
|
} else { |
|
setup->segments[grant_idx % GRANTS_PER_INDIRECT_FRAME] = |
|
(struct blkif_request_segment) { |
|
.gref = ref, |
|
.first_sect = fsect, |
|
.last_sect = lsect }; |
|
} |
|
|
|
(setup->grant_idx)++; |
|
} |
|
|
|
static void blkif_setup_extra_req(struct blkif_request *first, |
|
struct blkif_request *second) |
|
{ |
|
uint16_t nr_segments = first->u.rw.nr_segments; |
|
|
|
/* |
|
* The second request is only present when the first request uses |
|
* all its segments. It's always the continuity of the first one. |
|
*/ |
|
first->u.rw.nr_segments = BLKIF_MAX_SEGMENTS_PER_REQUEST; |
|
|
|
second->u.rw.nr_segments = nr_segments - BLKIF_MAX_SEGMENTS_PER_REQUEST; |
|
second->u.rw.sector_number = first->u.rw.sector_number + |
|
(BLKIF_MAX_SEGMENTS_PER_REQUEST * XEN_PAGE_SIZE) / 512; |
|
|
|
second->u.rw.handle = first->u.rw.handle; |
|
second->operation = first->operation; |
|
} |
|
|
|
static int blkif_queue_rw_req(struct request *req, struct blkfront_ring_info *rinfo) |
|
{ |
|
struct blkfront_info *info = rinfo->dev_info; |
|
struct blkif_request *ring_req, *extra_ring_req = NULL; |
|
struct blkif_request *final_ring_req, *final_extra_ring_req = NULL; |
|
unsigned long id, extra_id = NO_ASSOCIATED_ID; |
|
bool require_extra_req = false; |
|
int i; |
|
struct setup_rw_req setup = { |
|
.grant_idx = 0, |
|
.segments = NULL, |
|
.rinfo = rinfo, |
|
.need_copy = rq_data_dir(req) && info->feature_persistent, |
|
}; |
|
|
|
/* |
|
* Used to store if we are able to queue the request by just using |
|
* existing persistent grants, or if we have to get new grants, |
|
* as there are not sufficiently many free. |
|
*/ |
|
bool new_persistent_gnts = false; |
|
struct scatterlist *sg; |
|
int num_sg, max_grefs, num_grant; |
|
|
|
max_grefs = req->nr_phys_segments * GRANTS_PER_PSEG; |
|
if (max_grefs > BLKIF_MAX_SEGMENTS_PER_REQUEST) |
|
/* |
|
* If we are using indirect segments we need to account |
|
* for the indirect grefs used in the request. |
|
*/ |
|
max_grefs += INDIRECT_GREFS(max_grefs); |
|
|
|
/* Check if we have enough persistent grants to allocate a requests */ |
|
if (rinfo->persistent_gnts_c < max_grefs) { |
|
new_persistent_gnts = true; |
|
|
|
if (gnttab_alloc_grant_references( |
|
max_grefs - rinfo->persistent_gnts_c, |
|
&setup.gref_head) < 0) { |
|
gnttab_request_free_callback( |
|
&rinfo->callback, |
|
blkif_restart_queue_callback, |
|
rinfo, |
|
max_grefs - rinfo->persistent_gnts_c); |
|
return 1; |
|
} |
|
} |
|
|
|
/* Fill out a communications ring structure. */ |
|
id = blkif_ring_get_request(rinfo, req, &final_ring_req); |
|
ring_req = &rinfo->shadow[id].req; |
|
|
|
num_sg = blk_rq_map_sg(req->q, req, rinfo->shadow[id].sg); |
|
num_grant = 0; |
|
/* Calculate the number of grant used */ |
|
for_each_sg(rinfo->shadow[id].sg, sg, num_sg, i) |
|
num_grant += gnttab_count_grant(sg->offset, sg->length); |
|
|
|
require_extra_req = info->max_indirect_segments == 0 && |
|
num_grant > BLKIF_MAX_SEGMENTS_PER_REQUEST; |
|
BUG_ON(!HAS_EXTRA_REQ && require_extra_req); |
|
|
|
rinfo->shadow[id].num_sg = num_sg; |
|
if (num_grant > BLKIF_MAX_SEGMENTS_PER_REQUEST && |
|
likely(!require_extra_req)) { |
|
/* |
|
* The indirect operation can only be a BLKIF_OP_READ or |
|
* BLKIF_OP_WRITE |
|
*/ |
|
BUG_ON(req_op(req) == REQ_OP_FLUSH || req->cmd_flags & REQ_FUA); |
|
ring_req->operation = BLKIF_OP_INDIRECT; |
|
ring_req->u.indirect.indirect_op = rq_data_dir(req) ? |
|
BLKIF_OP_WRITE : BLKIF_OP_READ; |
|
ring_req->u.indirect.sector_number = (blkif_sector_t)blk_rq_pos(req); |
|
ring_req->u.indirect.handle = info->handle; |
|
ring_req->u.indirect.nr_segments = num_grant; |
|
} else { |
|
ring_req->u.rw.sector_number = (blkif_sector_t)blk_rq_pos(req); |
|
ring_req->u.rw.handle = info->handle; |
|
ring_req->operation = rq_data_dir(req) ? |
|
BLKIF_OP_WRITE : BLKIF_OP_READ; |
|
if (req_op(req) == REQ_OP_FLUSH || req->cmd_flags & REQ_FUA) { |
|
/* |
|
* Ideally we can do an unordered flush-to-disk. |
|
* In case the backend onlysupports barriers, use that. |
|
* A barrier request a superset of FUA, so we can |
|
* implement it the same way. (It's also a FLUSH+FUA, |
|
* since it is guaranteed ordered WRT previous writes.) |
|
*/ |
|
if (info->feature_flush && info->feature_fua) |
|
ring_req->operation = |
|
BLKIF_OP_WRITE_BARRIER; |
|
else if (info->feature_flush) |
|
ring_req->operation = |
|
BLKIF_OP_FLUSH_DISKCACHE; |
|
else |
|
ring_req->operation = 0; |
|
} |
|
ring_req->u.rw.nr_segments = num_grant; |
|
if (unlikely(require_extra_req)) { |
|
extra_id = blkif_ring_get_request(rinfo, req, |
|
&final_extra_ring_req); |
|
extra_ring_req = &rinfo->shadow[extra_id].req; |
|
|
|
/* |
|
* Only the first request contains the scatter-gather |
|
* list. |
|
*/ |
|
rinfo->shadow[extra_id].num_sg = 0; |
|
|
|
blkif_setup_extra_req(ring_req, extra_ring_req); |
|
|
|
/* Link the 2 requests together */ |
|
rinfo->shadow[extra_id].associated_id = id; |
|
rinfo->shadow[id].associated_id = extra_id; |
|
} |
|
} |
|
|
|
setup.ring_req = ring_req; |
|
setup.id = id; |
|
|
|
setup.require_extra_req = require_extra_req; |
|
if (unlikely(require_extra_req)) |
|
setup.extra_ring_req = extra_ring_req; |
|
|
|
for_each_sg(rinfo->shadow[id].sg, sg, num_sg, i) { |
|
BUG_ON(sg->offset + sg->length > PAGE_SIZE); |
|
|
|
if (setup.need_copy) { |
|
setup.bvec_off = sg->offset; |
|
setup.bvec_data = kmap_atomic(sg_page(sg)); |
|
} |
|
|
|
gnttab_foreach_grant_in_range(sg_page(sg), |
|
sg->offset, |
|
sg->length, |
|
blkif_setup_rw_req_grant, |
|
&setup); |
|
|
|
if (setup.need_copy) |
|
kunmap_atomic(setup.bvec_data); |
|
} |
|
if (setup.segments) |
|
kunmap_atomic(setup.segments); |
|
|
|
/* Copy request(s) to the ring page. */ |
|
*final_ring_req = *ring_req; |
|
rinfo->shadow[id].status = REQ_WAITING; |
|
if (unlikely(require_extra_req)) { |
|
*final_extra_ring_req = *extra_ring_req; |
|
rinfo->shadow[extra_id].status = REQ_WAITING; |
|
} |
|
|
|
if (new_persistent_gnts) |
|
gnttab_free_grant_references(setup.gref_head); |
|
|
|
return 0; |
|
} |
|
|
|
/* |
|
* Generate a Xen blkfront IO request from a blk layer request. Reads |
|
* and writes are handled as expected. |
|
* |
|
* @req: a request struct |
|
*/ |
|
static int blkif_queue_request(struct request *req, struct blkfront_ring_info *rinfo) |
|
{ |
|
if (unlikely(rinfo->dev_info->connected != BLKIF_STATE_CONNECTED)) |
|
return 1; |
|
|
|
if (unlikely(req_op(req) == REQ_OP_DISCARD || |
|
req_op(req) == REQ_OP_SECURE_ERASE)) |
|
return blkif_queue_discard_req(req, rinfo); |
|
else |
|
return blkif_queue_rw_req(req, rinfo); |
|
} |
|
|
|
static inline void flush_requests(struct blkfront_ring_info *rinfo) |
|
{ |
|
int notify; |
|
|
|
RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&rinfo->ring, notify); |
|
|
|
if (notify) |
|
notify_remote_via_irq(rinfo->irq); |
|
} |
|
|
|
static inline bool blkif_request_flush_invalid(struct request *req, |
|
struct blkfront_info *info) |
|
{ |
|
return (blk_rq_is_passthrough(req) || |
|
((req_op(req) == REQ_OP_FLUSH) && |
|
!info->feature_flush) || |
|
((req->cmd_flags & REQ_FUA) && |
|
!info->feature_fua)); |
|
} |
|
|
|
static blk_status_t blkif_queue_rq(struct blk_mq_hw_ctx *hctx, |
|
const struct blk_mq_queue_data *qd) |
|
{ |
|
unsigned long flags; |
|
int qid = hctx->queue_num; |
|
struct blkfront_info *info = hctx->queue->queuedata; |
|
struct blkfront_ring_info *rinfo = NULL; |
|
|
|
rinfo = get_rinfo(info, qid); |
|
blk_mq_start_request(qd->rq); |
|
spin_lock_irqsave(&rinfo->ring_lock, flags); |
|
if (RING_FULL(&rinfo->ring)) |
|
goto out_busy; |
|
|
|
if (blkif_request_flush_invalid(qd->rq, rinfo->dev_info)) |
|
goto out_err; |
|
|
|
if (blkif_queue_request(qd->rq, rinfo)) |
|
goto out_busy; |
|
|
|
flush_requests(rinfo); |
|
spin_unlock_irqrestore(&rinfo->ring_lock, flags); |
|
return BLK_STS_OK; |
|
|
|
out_err: |
|
spin_unlock_irqrestore(&rinfo->ring_lock, flags); |
|
return BLK_STS_IOERR; |
|
|
|
out_busy: |
|
blk_mq_stop_hw_queue(hctx); |
|
spin_unlock_irqrestore(&rinfo->ring_lock, flags); |
|
return BLK_STS_DEV_RESOURCE; |
|
} |
|
|
|
static void blkif_complete_rq(struct request *rq) |
|
{ |
|
blk_mq_end_request(rq, blkif_req(rq)->error); |
|
} |
|
|
|
static const struct blk_mq_ops blkfront_mq_ops = { |
|
.queue_rq = blkif_queue_rq, |
|
.complete = blkif_complete_rq, |
|
}; |
|
|
|
static void blkif_set_queue_limits(struct blkfront_info *info) |
|
{ |
|
struct request_queue *rq = info->rq; |
|
struct gendisk *gd = info->gd; |
|
unsigned int segments = info->max_indirect_segments ? : |
|
BLKIF_MAX_SEGMENTS_PER_REQUEST; |
|
|
|
blk_queue_flag_set(QUEUE_FLAG_VIRT, rq); |
|
|
|
if (info->feature_discard) { |
|
blk_queue_flag_set(QUEUE_FLAG_DISCARD, rq); |
|
blk_queue_max_discard_sectors(rq, get_capacity(gd)); |
|
rq->limits.discard_granularity = info->discard_granularity ?: |
|
info->physical_sector_size; |
|
rq->limits.discard_alignment = info->discard_alignment; |
|
if (info->feature_secdiscard) |
|
blk_queue_flag_set(QUEUE_FLAG_SECERASE, rq); |
|
} |
|
|
|
/* Hard sector size and max sectors impersonate the equiv. hardware. */ |
|
blk_queue_logical_block_size(rq, info->sector_size); |
|
blk_queue_physical_block_size(rq, info->physical_sector_size); |
|
blk_queue_max_hw_sectors(rq, (segments * XEN_PAGE_SIZE) / 512); |
|
|
|
/* Each segment in a request is up to an aligned page in size. */ |
|
blk_queue_segment_boundary(rq, PAGE_SIZE - 1); |
|
blk_queue_max_segment_size(rq, PAGE_SIZE); |
|
|
|
/* Ensure a merged request will fit in a single I/O ring slot. */ |
|
blk_queue_max_segments(rq, segments / GRANTS_PER_PSEG); |
|
|
|
/* Make sure buffer addresses are sector-aligned. */ |
|
blk_queue_dma_alignment(rq, 511); |
|
} |
|
|
|
static const char *flush_info(struct blkfront_info *info) |
|
{ |
|
if (info->feature_flush && info->feature_fua) |
|
return "barrier: enabled;"; |
|
else if (info->feature_flush) |
|
return "flush diskcache: enabled;"; |
|
else |
|
return "barrier or flush: disabled;"; |
|
} |
|
|
|
static void xlvbd_flush(struct blkfront_info *info) |
|
{ |
|
blk_queue_write_cache(info->rq, info->feature_flush ? true : false, |
|
info->feature_fua ? true : false); |
|
pr_info("blkfront: %s: %s %s %s %s %s\n", |
|
info->gd->disk_name, flush_info(info), |
|
"persistent grants:", info->feature_persistent ? |
|
"enabled;" : "disabled;", "indirect descriptors:", |
|
info->max_indirect_segments ? "enabled;" : "disabled;"); |
|
} |
|
|
|
static int xen_translate_vdev(int vdevice, int *minor, unsigned int *offset) |
|
{ |
|
int major; |
|
major = BLKIF_MAJOR(vdevice); |
|
*minor = BLKIF_MINOR(vdevice); |
|
switch (major) { |
|
case XEN_IDE0_MAJOR: |
|
*offset = (*minor / 64) + EMULATED_HD_DISK_NAME_OFFSET; |
|
*minor = ((*minor / 64) * PARTS_PER_DISK) + |
|
EMULATED_HD_DISK_MINOR_OFFSET; |
|
break; |
|
case XEN_IDE1_MAJOR: |
|
*offset = (*minor / 64) + 2 + EMULATED_HD_DISK_NAME_OFFSET; |
|
*minor = (((*minor / 64) + 2) * PARTS_PER_DISK) + |
|
EMULATED_HD_DISK_MINOR_OFFSET; |
|
break; |
|
case XEN_SCSI_DISK0_MAJOR: |
|
*offset = (*minor / PARTS_PER_DISK) + EMULATED_SD_DISK_NAME_OFFSET; |
|
*minor = *minor + EMULATED_SD_DISK_MINOR_OFFSET; |
|
break; |
|
case XEN_SCSI_DISK1_MAJOR: |
|
case XEN_SCSI_DISK2_MAJOR: |
|
case XEN_SCSI_DISK3_MAJOR: |
|
case XEN_SCSI_DISK4_MAJOR: |
|
case XEN_SCSI_DISK5_MAJOR: |
|
case XEN_SCSI_DISK6_MAJOR: |
|
case XEN_SCSI_DISK7_MAJOR: |
|
*offset = (*minor / PARTS_PER_DISK) + |
|
((major - XEN_SCSI_DISK1_MAJOR + 1) * 16) + |
|
EMULATED_SD_DISK_NAME_OFFSET; |
|
*minor = *minor + |
|
((major - XEN_SCSI_DISK1_MAJOR + 1) * 16 * PARTS_PER_DISK) + |
|
EMULATED_SD_DISK_MINOR_OFFSET; |
|
break; |
|
case XEN_SCSI_DISK8_MAJOR: |
|
case XEN_SCSI_DISK9_MAJOR: |
|
case XEN_SCSI_DISK10_MAJOR: |
|
case XEN_SCSI_DISK11_MAJOR: |
|
case XEN_SCSI_DISK12_MAJOR: |
|
case XEN_SCSI_DISK13_MAJOR: |
|
case XEN_SCSI_DISK14_MAJOR: |
|
case XEN_SCSI_DISK15_MAJOR: |
|
*offset = (*minor / PARTS_PER_DISK) + |
|
((major - XEN_SCSI_DISK8_MAJOR + 8) * 16) + |
|
EMULATED_SD_DISK_NAME_OFFSET; |
|
*minor = *minor + |
|
((major - XEN_SCSI_DISK8_MAJOR + 8) * 16 * PARTS_PER_DISK) + |
|
EMULATED_SD_DISK_MINOR_OFFSET; |
|
break; |
|
case XENVBD_MAJOR: |
|
*offset = *minor / PARTS_PER_DISK; |
|
break; |
|
default: |
|
printk(KERN_WARNING "blkfront: your disk configuration is " |
|
"incorrect, please use an xvd device instead\n"); |
|
return -ENODEV; |
|
} |
|
return 0; |
|
} |
|
|
|
static char *encode_disk_name(char *ptr, unsigned int n) |
|
{ |
|
if (n >= 26) |
|
ptr = encode_disk_name(ptr, n / 26 - 1); |
|
*ptr = 'a' + n % 26; |
|
return ptr + 1; |
|
} |
|
|
|
static int xlvbd_alloc_gendisk(blkif_sector_t capacity, |
|
struct blkfront_info *info, u16 sector_size, |
|
unsigned int physical_sector_size) |
|
{ |
|
struct gendisk *gd; |
|
int nr_minors = 1; |
|
int err; |
|
unsigned int offset; |
|
int minor; |
|
int nr_parts; |
|
char *ptr; |
|
|
|
BUG_ON(info->gd != NULL); |
|
BUG_ON(info->rq != NULL); |
|
|
|
if ((info->vdevice>>EXT_SHIFT) > 1) { |
|
/* this is above the extended range; something is wrong */ |
|
printk(KERN_WARNING "blkfront: vdevice 0x%x is above the extended range; ignoring\n", info->vdevice); |
|
return -ENODEV; |
|
} |
|
|
|
if (!VDEV_IS_EXTENDED(info->vdevice)) { |
|
err = xen_translate_vdev(info->vdevice, &minor, &offset); |
|
if (err) |
|
return err; |
|
nr_parts = PARTS_PER_DISK; |
|
} else { |
|
minor = BLKIF_MINOR_EXT(info->vdevice); |
|
nr_parts = PARTS_PER_EXT_DISK; |
|
offset = minor / nr_parts; |
|
if (xen_hvm_domain() && offset < EMULATED_HD_DISK_NAME_OFFSET + 4) |
|
printk(KERN_WARNING "blkfront: vdevice 0x%x might conflict with " |
|
"emulated IDE disks,\n\t choose an xvd device name" |
|
"from xvde on\n", info->vdevice); |
|
} |
|
if (minor >> MINORBITS) { |
|
pr_warn("blkfront: %#x's minor (%#x) out of range; ignoring\n", |
|
info->vdevice, minor); |
|
return -ENODEV; |
|
} |
|
|
|
if ((minor % nr_parts) == 0) |
|
nr_minors = nr_parts; |
|
|
|
err = xlbd_reserve_minors(minor, nr_minors); |
|
if (err) |
|
return err; |
|
|
|
memset(&info->tag_set, 0, sizeof(info->tag_set)); |
|
info->tag_set.ops = &blkfront_mq_ops; |
|
info->tag_set.nr_hw_queues = info->nr_rings; |
|
if (HAS_EXTRA_REQ && info->max_indirect_segments == 0) { |
|
/* |
|
* When indirect descriptior is not supported, the I/O request |
|
* will be split between multiple request in the ring. |
|
* To avoid problems when sending the request, divide by |
|
* 2 the depth of the queue. |
|
*/ |
|
info->tag_set.queue_depth = BLK_RING_SIZE(info) / 2; |
|
} else |
|
info->tag_set.queue_depth = BLK_RING_SIZE(info); |
|
info->tag_set.numa_node = NUMA_NO_NODE; |
|
info->tag_set.flags = BLK_MQ_F_SHOULD_MERGE; |
|
info->tag_set.cmd_size = sizeof(struct blkif_req); |
|
info->tag_set.driver_data = info; |
|
|
|
err = blk_mq_alloc_tag_set(&info->tag_set); |
|
if (err) |
|
goto out_release_minors; |
|
|
|
gd = blk_mq_alloc_disk(&info->tag_set, info); |
|
if (IS_ERR(gd)) { |
|
err = PTR_ERR(gd); |
|
goto out_free_tag_set; |
|
} |
|
|
|
strcpy(gd->disk_name, DEV_NAME); |
|
ptr = encode_disk_name(gd->disk_name + sizeof(DEV_NAME) - 1, offset); |
|
BUG_ON(ptr >= gd->disk_name + DISK_NAME_LEN); |
|
if (nr_minors > 1) |
|
*ptr = 0; |
|
else |
|
snprintf(ptr, gd->disk_name + DISK_NAME_LEN - ptr, |
|
"%d", minor & (nr_parts - 1)); |
|
|
|
gd->major = XENVBD_MAJOR; |
|
gd->first_minor = minor; |
|
gd->minors = nr_minors; |
|
gd->fops = &xlvbd_block_fops; |
|
gd->private_data = info; |
|
set_capacity(gd, capacity); |
|
|
|
info->rq = gd->queue; |
|
info->gd = gd; |
|
info->sector_size = sector_size; |
|
info->physical_sector_size = physical_sector_size; |
|
blkif_set_queue_limits(info); |
|
|
|
xlvbd_flush(info); |
|
|
|
if (info->vdisk_info & VDISK_READONLY) |
|
set_disk_ro(gd, 1); |
|
if (info->vdisk_info & VDISK_REMOVABLE) |
|
gd->flags |= GENHD_FL_REMOVABLE; |
|
|
|
return 0; |
|
|
|
out_free_tag_set: |
|
blk_mq_free_tag_set(&info->tag_set); |
|
out_release_minors: |
|
xlbd_release_minors(minor, nr_minors); |
|
return err; |
|
} |
|
|
|
/* Already hold rinfo->ring_lock. */ |
|
static inline void kick_pending_request_queues_locked(struct blkfront_ring_info *rinfo) |
|
{ |
|
if (!RING_FULL(&rinfo->ring)) |
|
blk_mq_start_stopped_hw_queues(rinfo->dev_info->rq, true); |
|
} |
|
|
|
static void kick_pending_request_queues(struct blkfront_ring_info *rinfo) |
|
{ |
|
unsigned long flags; |
|
|
|
spin_lock_irqsave(&rinfo->ring_lock, flags); |
|
kick_pending_request_queues_locked(rinfo); |
|
spin_unlock_irqrestore(&rinfo->ring_lock, flags); |
|
} |
|
|
|
static void blkif_restart_queue(struct work_struct *work) |
|
{ |
|
struct blkfront_ring_info *rinfo = container_of(work, struct blkfront_ring_info, work); |
|
|
|
if (rinfo->dev_info->connected == BLKIF_STATE_CONNECTED) |
|
kick_pending_request_queues(rinfo); |
|
} |
|
|
|
static void blkif_free_ring(struct blkfront_ring_info *rinfo) |
|
{ |
|
struct grant *persistent_gnt, *n; |
|
struct blkfront_info *info = rinfo->dev_info; |
|
int i, j, segs; |
|
|
|
/* |
|
* Remove indirect pages, this only happens when using indirect |
|
* descriptors but not persistent grants |
|
*/ |
|
if (!list_empty(&rinfo->indirect_pages)) { |
|
struct page *indirect_page, *n; |
|
|
|
BUG_ON(info->feature_persistent); |
|
list_for_each_entry_safe(indirect_page, n, &rinfo->indirect_pages, lru) { |
|
list_del(&indirect_page->lru); |
|
__free_page(indirect_page); |
|
} |
|
} |
|
|
|
/* Remove all persistent grants. */ |
|
if (!list_empty(&rinfo->grants)) { |
|
list_for_each_entry_safe(persistent_gnt, n, |
|
&rinfo->grants, node) { |
|
list_del(&persistent_gnt->node); |
|
if (persistent_gnt->gref != GRANT_INVALID_REF) { |
|
gnttab_end_foreign_access(persistent_gnt->gref, |
|
0, 0UL); |
|
rinfo->persistent_gnts_c--; |
|
} |
|
if (info->feature_persistent) |
|
__free_page(persistent_gnt->page); |
|
kfree(persistent_gnt); |
|
} |
|
} |
|
BUG_ON(rinfo->persistent_gnts_c != 0); |
|
|
|
for (i = 0; i < BLK_RING_SIZE(info); i++) { |
|
/* |
|
* Clear persistent grants present in requests already |
|
* on the shared ring |
|
*/ |
|
if (!rinfo->shadow[i].request) |
|
goto free_shadow; |
|
|
|
segs = rinfo->shadow[i].req.operation == BLKIF_OP_INDIRECT ? |
|
rinfo->shadow[i].req.u.indirect.nr_segments : |
|
rinfo->shadow[i].req.u.rw.nr_segments; |
|
for (j = 0; j < segs; j++) { |
|
persistent_gnt = rinfo->shadow[i].grants_used[j]; |
|
gnttab_end_foreign_access(persistent_gnt->gref, 0, 0UL); |
|
if (info->feature_persistent) |
|
__free_page(persistent_gnt->page); |
|
kfree(persistent_gnt); |
|
} |
|
|
|
if (rinfo->shadow[i].req.operation != BLKIF_OP_INDIRECT) |
|
/* |
|
* If this is not an indirect operation don't try to |
|
* free indirect segments |
|
*/ |
|
goto free_shadow; |
|
|
|
for (j = 0; j < INDIRECT_GREFS(segs); j++) { |
|
persistent_gnt = rinfo->shadow[i].indirect_grants[j]; |
|
gnttab_end_foreign_access(persistent_gnt->gref, 0, 0UL); |
|
__free_page(persistent_gnt->page); |
|
kfree(persistent_gnt); |
|
} |
|
|
|
free_shadow: |
|
kvfree(rinfo->shadow[i].grants_used); |
|
rinfo->shadow[i].grants_used = NULL; |
|
kvfree(rinfo->shadow[i].indirect_grants); |
|
rinfo->shadow[i].indirect_grants = NULL; |
|
kvfree(rinfo->shadow[i].sg); |
|
rinfo->shadow[i].sg = NULL; |
|
} |
|
|
|
/* No more gnttab callback work. */ |
|
gnttab_cancel_free_callback(&rinfo->callback); |
|
|
|
/* Flush gnttab callback work. Must be done with no locks held. */ |
|
flush_work(&rinfo->work); |
|
|
|
/* Free resources associated with old device channel. */ |
|
for (i = 0; i < info->nr_ring_pages; i++) { |
|
if (rinfo->ring_ref[i] != GRANT_INVALID_REF) { |
|
gnttab_end_foreign_access(rinfo->ring_ref[i], 0, 0); |
|
rinfo->ring_ref[i] = GRANT_INVALID_REF; |
|
} |
|
} |
|
free_pages_exact(rinfo->ring.sring, |
|
info->nr_ring_pages * XEN_PAGE_SIZE); |
|
rinfo->ring.sring = NULL; |
|
|
|
if (rinfo->irq) |
|
unbind_from_irqhandler(rinfo->irq, rinfo); |
|
rinfo->evtchn = rinfo->irq = 0; |
|
} |
|
|
|
static void blkif_free(struct blkfront_info *info, int suspend) |
|
{ |
|
unsigned int i; |
|
struct blkfront_ring_info *rinfo; |
|
|
|
/* Prevent new requests being issued until we fix things up. */ |
|
info->connected = suspend ? |
|
BLKIF_STATE_SUSPENDED : BLKIF_STATE_DISCONNECTED; |
|
/* No more blkif_request(). */ |
|
if (info->rq) |
|
blk_mq_stop_hw_queues(info->rq); |
|
|
|
for_each_rinfo(info, rinfo, i) |
|
blkif_free_ring(rinfo); |
|
|
|
kvfree(info->rinfo); |
|
info->rinfo = NULL; |
|
info->nr_rings = 0; |
|
} |
|
|
|
struct copy_from_grant { |
|
const struct blk_shadow *s; |
|
unsigned int grant_idx; |
|
unsigned int bvec_offset; |
|
char *bvec_data; |
|
}; |
|
|
|
static void blkif_copy_from_grant(unsigned long gfn, unsigned int offset, |
|
unsigned int len, void *data) |
|
{ |
|
struct copy_from_grant *info = data; |
|
char *shared_data; |
|
/* Convenient aliases */ |
|
const struct blk_shadow *s = info->s; |
|
|
|
shared_data = kmap_atomic(s->grants_used[info->grant_idx]->page); |
|
|
|
memcpy(info->bvec_data + info->bvec_offset, |
|
shared_data + offset, len); |
|
|
|
info->bvec_offset += len; |
|
info->grant_idx++; |
|
|
|
kunmap_atomic(shared_data); |
|
} |
|
|
|
static enum blk_req_status blkif_rsp_to_req_status(int rsp) |
|
{ |
|
switch (rsp) |
|
{ |
|
case BLKIF_RSP_OKAY: |
|
return REQ_DONE; |
|
case BLKIF_RSP_EOPNOTSUPP: |
|
return REQ_EOPNOTSUPP; |
|
case BLKIF_RSP_ERROR: |
|
default: |
|
return REQ_ERROR; |
|
} |
|
} |
|
|
|
/* |
|
* Get the final status of the block request based on two ring response |
|
*/ |
|
static int blkif_get_final_status(enum blk_req_status s1, |
|
enum blk_req_status s2) |
|
{ |
|
BUG_ON(s1 < REQ_DONE); |
|
BUG_ON(s2 < REQ_DONE); |
|
|
|
if (s1 == REQ_ERROR || s2 == REQ_ERROR) |
|
return BLKIF_RSP_ERROR; |
|
else if (s1 == REQ_EOPNOTSUPP || s2 == REQ_EOPNOTSUPP) |
|
return BLKIF_RSP_EOPNOTSUPP; |
|
return BLKIF_RSP_OKAY; |
|
} |
|
|
|
/* |
|
* Return values: |
|
* 1 response processed. |
|
* 0 missing further responses. |
|
* -1 error while processing. |
|
*/ |
|
static int blkif_completion(unsigned long *id, |
|
struct blkfront_ring_info *rinfo, |
|
struct blkif_response *bret) |
|
{ |
|
int i = 0; |
|
struct scatterlist *sg; |
|
int num_sg, num_grant; |
|
struct blkfront_info *info = rinfo->dev_info; |
|
struct blk_shadow *s = &rinfo->shadow[*id]; |
|
struct copy_from_grant data = { |
|
.grant_idx = 0, |
|
}; |
|
|
|
num_grant = s->req.operation == BLKIF_OP_INDIRECT ? |
|
s->req.u.indirect.nr_segments : s->req.u.rw.nr_segments; |
|
|
|
/* The I/O request may be split in two. */ |
|
if (unlikely(s->associated_id != NO_ASSOCIATED_ID)) { |
|
struct blk_shadow *s2 = &rinfo->shadow[s->associated_id]; |
|
|
|
/* Keep the status of the current response in shadow. */ |
|
s->status = blkif_rsp_to_req_status(bret->status); |
|
|
|
/* Wait the second response if not yet here. */ |
|
if (s2->status < REQ_DONE) |
|
return 0; |
|
|
|
bret->status = blkif_get_final_status(s->status, |
|
s2->status); |
|
|
|
/* |
|
* All the grants is stored in the first shadow in order |
|
* to make the completion code simpler. |
|
*/ |
|
num_grant += s2->req.u.rw.nr_segments; |
|
|
|
/* |
|
* The two responses may not come in order. Only the |
|
* first request will store the scatter-gather list. |
|
*/ |
|
if (s2->num_sg != 0) { |
|
/* Update "id" with the ID of the first response. */ |
|
*id = s->associated_id; |
|
s = s2; |
|
} |
|
|
|
/* |
|
* We don't need anymore the second request, so recycling |
|
* it now. |
|
*/ |
|
if (add_id_to_freelist(rinfo, s->associated_id)) |
|
WARN(1, "%s: can't recycle the second part (id = %ld) of the request\n", |
|
info->gd->disk_name, s->associated_id); |
|
} |
|
|
|
data.s = s; |
|
num_sg = s->num_sg; |
|
|
|
if (bret->operation == BLKIF_OP_READ && info->feature_persistent) { |
|
for_each_sg(s->sg, sg, num_sg, i) { |
|
BUG_ON(sg->offset + sg->length > PAGE_SIZE); |
|
|
|
data.bvec_offset = sg->offset; |
|
data.bvec_data = kmap_atomic(sg_page(sg)); |
|
|
|
gnttab_foreach_grant_in_range(sg_page(sg), |
|
sg->offset, |
|
sg->length, |
|
blkif_copy_from_grant, |
|
&data); |
|
|
|
kunmap_atomic(data.bvec_data); |
|
} |
|
} |
|
/* Add the persistent grant into the list of free grants */ |
|
for (i = 0; i < num_grant; i++) { |
|
if (!gnttab_try_end_foreign_access(s->grants_used[i]->gref)) { |
|
/* |
|
* If the grant is still mapped by the backend (the |
|
* backend has chosen to make this grant persistent) |
|
* we add it at the head of the list, so it will be |
|
* reused first. |
|
*/ |
|
if (!info->feature_persistent) { |
|
pr_alert("backed has not unmapped grant: %u\n", |
|
s->grants_used[i]->gref); |
|
return -1; |
|
} |
|
list_add(&s->grants_used[i]->node, &rinfo->grants); |
|
rinfo->persistent_gnts_c++; |
|
} else { |
|
/* |
|
* If the grant is not mapped by the backend we add it |
|
* to the tail of the list, so it will not be picked |
|
* again unless we run out of persistent grants. |
|
*/ |
|
s->grants_used[i]->gref = GRANT_INVALID_REF; |
|
list_add_tail(&s->grants_used[i]->node, &rinfo->grants); |
|
} |
|
} |
|
if (s->req.operation == BLKIF_OP_INDIRECT) { |
|
for (i = 0; i < INDIRECT_GREFS(num_grant); i++) { |
|
if (!gnttab_try_end_foreign_access(s->indirect_grants[i]->gref)) { |
|
if (!info->feature_persistent) { |
|
pr_alert("backed has not unmapped grant: %u\n", |
|
s->indirect_grants[i]->gref); |
|
return -1; |
|
} |
|
list_add(&s->indirect_grants[i]->node, &rinfo->grants); |
|
rinfo->persistent_gnts_c++; |
|
} else { |
|
struct page *indirect_page; |
|
|
|
/* |
|
* Add the used indirect page back to the list of |
|
* available pages for indirect grefs. |
|
*/ |
|
if (!info->feature_persistent) { |
|
indirect_page = s->indirect_grants[i]->page; |
|
list_add(&indirect_page->lru, &rinfo->indirect_pages); |
|
} |
|
s->indirect_grants[i]->gref = GRANT_INVALID_REF; |
|
list_add_tail(&s->indirect_grants[i]->node, &rinfo->grants); |
|
} |
|
} |
|
} |
|
|
|
return 1; |
|
} |
|
|
|
static irqreturn_t blkif_interrupt(int irq, void *dev_id) |
|
{ |
|
struct request *req; |
|
struct blkif_response bret; |
|
RING_IDX i, rp; |
|
unsigned long flags; |
|
struct blkfront_ring_info *rinfo = (struct blkfront_ring_info *)dev_id; |
|
struct blkfront_info *info = rinfo->dev_info; |
|
unsigned int eoiflag = XEN_EOI_FLAG_SPURIOUS; |
|
|
|
if (unlikely(info->connected != BLKIF_STATE_CONNECTED)) { |
|
xen_irq_lateeoi(irq, XEN_EOI_FLAG_SPURIOUS); |
|
return IRQ_HANDLED; |
|
} |
|
|
|
spin_lock_irqsave(&rinfo->ring_lock, flags); |
|
again: |
|
rp = READ_ONCE(rinfo->ring.sring->rsp_prod); |
|
virt_rmb(); /* Ensure we see queued responses up to 'rp'. */ |
|
if (RING_RESPONSE_PROD_OVERFLOW(&rinfo->ring, rp)) { |
|
pr_alert("%s: illegal number of responses %u\n", |
|
info->gd->disk_name, rp - rinfo->ring.rsp_cons); |
|
goto err; |
|
} |
|
|
|
for (i = rinfo->ring.rsp_cons; i != rp; i++) { |
|
unsigned long id; |
|
unsigned int op; |
|
|
|
eoiflag = 0; |
|
|
|
RING_COPY_RESPONSE(&rinfo->ring, i, &bret); |
|
id = bret.id; |
|
|
|
/* |
|
* The backend has messed up and given us an id that we would |
|
* never have given to it (we stamp it up to BLK_RING_SIZE - |
|
* look in get_id_from_freelist. |
|
*/ |
|
if (id >= BLK_RING_SIZE(info)) { |
|
pr_alert("%s: response has incorrect id (%ld)\n", |
|
info->gd->disk_name, id); |
|
goto err; |
|
} |
|
if (rinfo->shadow[id].status != REQ_WAITING) { |
|
pr_alert("%s: response references no pending request\n", |
|
info->gd->disk_name); |
|
goto err; |
|
} |
|
|
|
rinfo->shadow[id].status = REQ_PROCESSING; |
|
req = rinfo->shadow[id].request; |
|
|
|
op = rinfo->shadow[id].req.operation; |
|
if (op == BLKIF_OP_INDIRECT) |
|
op = rinfo->shadow[id].req.u.indirect.indirect_op; |
|
if (bret.operation != op) { |
|
pr_alert("%s: response has wrong operation (%u instead of %u)\n", |
|
info->gd->disk_name, bret.operation, op); |
|
goto err; |
|
} |
|
|
|
if (bret.operation != BLKIF_OP_DISCARD) { |
|
int ret; |
|
|
|
/* |
|
* We may need to wait for an extra response if the |
|
* I/O request is split in 2 |
|
*/ |
|
ret = blkif_completion(&id, rinfo, &bret); |
|
if (!ret) |
|
continue; |
|
if (unlikely(ret < 0)) |
|
goto err; |
|
} |
|
|
|
if (add_id_to_freelist(rinfo, id)) { |
|
WARN(1, "%s: response to %s (id %ld) couldn't be recycled!\n", |
|
info->gd->disk_name, op_name(bret.operation), id); |
|
continue; |
|
} |
|
|
|
if (bret.status == BLKIF_RSP_OKAY) |
|
blkif_req(req)->error = BLK_STS_OK; |
|
else |
|
blkif_req(req)->error = BLK_STS_IOERR; |
|
|
|
switch (bret.operation) { |
|
case BLKIF_OP_DISCARD: |
|
if (unlikely(bret.status == BLKIF_RSP_EOPNOTSUPP)) { |
|
struct request_queue *rq = info->rq; |
|
|
|
pr_warn_ratelimited("blkfront: %s: %s op failed\n", |
|
info->gd->disk_name, op_name(bret.operation)); |
|
blkif_req(req)->error = BLK_STS_NOTSUPP; |
|
info->feature_discard = 0; |
|
info->feature_secdiscard = 0; |
|
blk_queue_flag_clear(QUEUE_FLAG_DISCARD, rq); |
|
blk_queue_flag_clear(QUEUE_FLAG_SECERASE, rq); |
|
} |
|
break; |
|
case BLKIF_OP_FLUSH_DISKCACHE: |
|
case BLKIF_OP_WRITE_BARRIER: |
|
if (unlikely(bret.status == BLKIF_RSP_EOPNOTSUPP)) { |
|
pr_warn_ratelimited("blkfront: %s: %s op failed\n", |
|
info->gd->disk_name, op_name(bret.operation)); |
|
blkif_req(req)->error = BLK_STS_NOTSUPP; |
|
} |
|
if (unlikely(bret.status == BLKIF_RSP_ERROR && |
|
rinfo->shadow[id].req.u.rw.nr_segments == 0)) { |
|
pr_warn_ratelimited("blkfront: %s: empty %s op failed\n", |
|
info->gd->disk_name, op_name(bret.operation)); |
|
blkif_req(req)->error = BLK_STS_NOTSUPP; |
|
} |
|
if (unlikely(blkif_req(req)->error)) { |
|
if (blkif_req(req)->error == BLK_STS_NOTSUPP) |
|
blkif_req(req)->error = BLK_STS_OK; |
|
info->feature_fua = 0; |
|
info->feature_flush = 0; |
|
xlvbd_flush(info); |
|
} |
|
fallthrough; |
|
case BLKIF_OP_READ: |
|
case BLKIF_OP_WRITE: |
|
if (unlikely(bret.status != BLKIF_RSP_OKAY)) |
|
dev_dbg_ratelimited(&info->xbdev->dev, |
|
"Bad return from blkdev data request: %#x\n", |
|
bret.status); |
|
|
|
break; |
|
default: |
|
BUG(); |
|
} |
|
|
|
if (likely(!blk_should_fake_timeout(req->q))) |
|
blk_mq_complete_request(req); |
|
} |
|
|
|
rinfo->ring.rsp_cons = i; |
|
|
|
if (i != rinfo->ring.req_prod_pvt) { |
|
int more_to_do; |
|
RING_FINAL_CHECK_FOR_RESPONSES(&rinfo->ring, more_to_do); |
|
if (more_to_do) |
|
goto again; |
|
} else |
|
rinfo->ring.sring->rsp_event = i + 1; |
|
|
|
kick_pending_request_queues_locked(rinfo); |
|
|
|
spin_unlock_irqrestore(&rinfo->ring_lock, flags); |
|
|
|
xen_irq_lateeoi(irq, eoiflag); |
|
|
|
return IRQ_HANDLED; |
|
|
|
err: |
|
info->connected = BLKIF_STATE_ERROR; |
|
|
|
spin_unlock_irqrestore(&rinfo->ring_lock, flags); |
|
|
|
/* No EOI in order to avoid further interrupts. */ |
|
|
|
pr_alert("%s disabled for further use\n", info->gd->disk_name); |
|
return IRQ_HANDLED; |
|
} |
|
|
|
|
|
static int setup_blkring(struct xenbus_device *dev, |
|
struct blkfront_ring_info *rinfo) |
|
{ |
|
struct blkif_sring *sring; |
|
int err, i; |
|
struct blkfront_info *info = rinfo->dev_info; |
|
unsigned long ring_size = info->nr_ring_pages * XEN_PAGE_SIZE; |
|
grant_ref_t gref[XENBUS_MAX_RING_GRANTS]; |
|
|
|
for (i = 0; i < info->nr_ring_pages; i++) |
|
rinfo->ring_ref[i] = GRANT_INVALID_REF; |
|
|
|
sring = alloc_pages_exact(ring_size, GFP_NOIO); |
|
if (!sring) { |
|
xenbus_dev_fatal(dev, -ENOMEM, "allocating shared ring"); |
|
return -ENOMEM; |
|
} |
|
SHARED_RING_INIT(sring); |
|
FRONT_RING_INIT(&rinfo->ring, sring, ring_size); |
|
|
|
err = xenbus_grant_ring(dev, rinfo->ring.sring, info->nr_ring_pages, gref); |
|
if (err < 0) { |
|
free_pages_exact(sring, ring_size); |
|
rinfo->ring.sring = NULL; |
|
goto fail; |
|
} |
|
for (i = 0; i < info->nr_ring_pages; i++) |
|
rinfo->ring_ref[i] = gref[i]; |
|
|
|
err = xenbus_alloc_evtchn(dev, &rinfo->evtchn); |
|
if (err) |
|
goto fail; |
|
|
|
err = bind_evtchn_to_irqhandler_lateeoi(rinfo->evtchn, blkif_interrupt, |
|
0, "blkif", rinfo); |
|
if (err <= 0) { |
|
xenbus_dev_fatal(dev, err, |
|
"bind_evtchn_to_irqhandler failed"); |
|
goto fail; |
|
} |
|
rinfo->irq = err; |
|
|
|
return 0; |
|
fail: |
|
blkif_free(info, 0); |
|
return err; |
|
} |
|
|
|
/* |
|
* Write out per-ring/queue nodes including ring-ref and event-channel, and each |
|
* ring buffer may have multi pages depending on ->nr_ring_pages. |
|
*/ |
|
static int write_per_ring_nodes(struct xenbus_transaction xbt, |
|
struct blkfront_ring_info *rinfo, const char *dir) |
|
{ |
|
int err; |
|
unsigned int i; |
|
const char *message = NULL; |
|
struct blkfront_info *info = rinfo->dev_info; |
|
|
|
if (info->nr_ring_pages == 1) { |
|
err = xenbus_printf(xbt, dir, "ring-ref", "%u", rinfo->ring_ref[0]); |
|
if (err) { |
|
message = "writing ring-ref"; |
|
goto abort_transaction; |
|
} |
|
} else { |
|
for (i = 0; i < info->nr_ring_pages; i++) { |
|
char ring_ref_name[RINGREF_NAME_LEN]; |
|
|
|
snprintf(ring_ref_name, RINGREF_NAME_LEN, "ring-ref%u", i); |
|
err = xenbus_printf(xbt, dir, ring_ref_name, |
|
"%u", rinfo->ring_ref[i]); |
|
if (err) { |
|
message = "writing ring-ref"; |
|
goto abort_transaction; |
|
} |
|
} |
|
} |
|
|
|
err = xenbus_printf(xbt, dir, "event-channel", "%u", rinfo->evtchn); |
|
if (err) { |
|
message = "writing event-channel"; |
|
goto abort_transaction; |
|
} |
|
|
|
return 0; |
|
|
|
abort_transaction: |
|
xenbus_transaction_end(xbt, 1); |
|
if (message) |
|
xenbus_dev_fatal(info->xbdev, err, "%s", message); |
|
|
|
return err; |
|
} |
|
|
|
/* Common code used when first setting up, and when resuming. */ |
|
static int talk_to_blkback(struct xenbus_device *dev, |
|
struct blkfront_info *info) |
|
{ |
|
const char *message = NULL; |
|
struct xenbus_transaction xbt; |
|
int err; |
|
unsigned int i, max_page_order; |
|
unsigned int ring_page_order; |
|
struct blkfront_ring_info *rinfo; |
|
|
|
if (!info) |
|
return -ENODEV; |
|
|
|
max_page_order = xenbus_read_unsigned(info->xbdev->otherend, |
|
"max-ring-page-order", 0); |
|
ring_page_order = min(xen_blkif_max_ring_order, max_page_order); |
|
info->nr_ring_pages = 1 << ring_page_order; |
|
|
|
err = negotiate_mq(info); |
|
if (err) |
|
goto destroy_blkring; |
|
|
|
for_each_rinfo(info, rinfo, i) { |
|
/* Create shared ring, alloc event channel. */ |
|
err = setup_blkring(dev, rinfo); |
|
if (err) |
|
goto destroy_blkring; |
|
} |
|
|
|
again: |
|
err = xenbus_transaction_start(&xbt); |
|
if (err) { |
|
xenbus_dev_fatal(dev, err, "starting transaction"); |
|
goto destroy_blkring; |
|
} |
|
|
|
if (info->nr_ring_pages > 1) { |
|
err = xenbus_printf(xbt, dev->nodename, "ring-page-order", "%u", |
|
ring_page_order); |
|
if (err) { |
|
message = "writing ring-page-order"; |
|
goto abort_transaction; |
|
} |
|
} |
|
|
|
/* We already got the number of queues/rings in _probe */ |
|
if (info->nr_rings == 1) { |
|
err = write_per_ring_nodes(xbt, info->rinfo, dev->nodename); |
|
if (err) |
|
goto destroy_blkring; |
|
} else { |
|
char *path; |
|
size_t pathsize; |
|
|
|
err = xenbus_printf(xbt, dev->nodename, "multi-queue-num-queues", "%u", |
|
info->nr_rings); |
|
if (err) { |
|
message = "writing multi-queue-num-queues"; |
|
goto abort_transaction; |
|
} |
|
|
|
pathsize = strlen(dev->nodename) + QUEUE_NAME_LEN; |
|
path = kmalloc(pathsize, GFP_KERNEL); |
|
if (!path) { |
|
err = -ENOMEM; |
|
message = "ENOMEM while writing ring references"; |
|
goto abort_transaction; |
|
} |
|
|
|
for_each_rinfo(info, rinfo, i) { |
|
memset(path, 0, pathsize); |
|
snprintf(path, pathsize, "%s/queue-%u", dev->nodename, i); |
|
err = write_per_ring_nodes(xbt, rinfo, path); |
|
if (err) { |
|
kfree(path); |
|
goto destroy_blkring; |
|
} |
|
} |
|
kfree(path); |
|
} |
|
err = xenbus_printf(xbt, dev->nodename, "protocol", "%s", |
|
XEN_IO_PROTO_ABI_NATIVE); |
|
if (err) { |
|
message = "writing protocol"; |
|
goto abort_transaction; |
|
} |
|
err = xenbus_printf(xbt, dev->nodename, "feature-persistent", "%u", |
|
info->feature_persistent); |
|
if (err) |
|
dev_warn(&dev->dev, |
|
"writing persistent grants feature to xenbus"); |
|
|
|
err = xenbus_transaction_end(xbt, 0); |
|
if (err) { |
|
if (err == -EAGAIN) |
|
goto again; |
|
xenbus_dev_fatal(dev, err, "completing transaction"); |
|
goto destroy_blkring; |
|
} |
|
|
|
for_each_rinfo(info, rinfo, i) { |
|
unsigned int j; |
|
|
|
for (j = 0; j < BLK_RING_SIZE(info); j++) |
|
rinfo->shadow[j].req.u.rw.id = j + 1; |
|
rinfo->shadow[BLK_RING_SIZE(info)-1].req.u.rw.id = 0x0fffffff; |
|
} |
|
xenbus_switch_state(dev, XenbusStateInitialised); |
|
|
|
return 0; |
|
|
|
abort_transaction: |
|
xenbus_transaction_end(xbt, 1); |
|
if (message) |
|
xenbus_dev_fatal(dev, err, "%s", message); |
|
destroy_blkring: |
|
blkif_free(info, 0); |
|
return err; |
|
} |
|
|
|
static int negotiate_mq(struct blkfront_info *info) |
|
{ |
|
unsigned int backend_max_queues; |
|
unsigned int i; |
|
struct blkfront_ring_info *rinfo; |
|
|
|
BUG_ON(info->nr_rings); |
|
|
|
/* Check if backend supports multiple queues. */ |
|
backend_max_queues = xenbus_read_unsigned(info->xbdev->otherend, |
|
"multi-queue-max-queues", 1); |
|
info->nr_rings = min(backend_max_queues, xen_blkif_max_queues); |
|
/* We need at least one ring. */ |
|
if (!info->nr_rings) |
|
info->nr_rings = 1; |
|
|
|
info->rinfo_size = struct_size(info->rinfo, shadow, |
|
BLK_RING_SIZE(info)); |
|
info->rinfo = kvcalloc(info->nr_rings, info->rinfo_size, GFP_KERNEL); |
|
if (!info->rinfo) { |
|
xenbus_dev_fatal(info->xbdev, -ENOMEM, "allocating ring_info structure"); |
|
info->nr_rings = 0; |
|
return -ENOMEM; |
|
} |
|
|
|
for_each_rinfo(info, rinfo, i) { |
|
INIT_LIST_HEAD(&rinfo->indirect_pages); |
|
INIT_LIST_HEAD(&rinfo->grants); |
|
rinfo->dev_info = info; |
|
INIT_WORK(&rinfo->work, blkif_restart_queue); |
|
spin_lock_init(&rinfo->ring_lock); |
|
} |
|
return 0; |
|
} |
|
|
|
/* Enable the persistent grants feature. */ |
|
static bool feature_persistent = true; |
|
module_param(feature_persistent, bool, 0644); |
|
MODULE_PARM_DESC(feature_persistent, |
|
"Enables the persistent grants feature"); |
|
|
|
/* |
|
* Entry point to this code when a new device is created. Allocate the basic |
|
* structures and the ring buffer for communication with the backend, and |
|
* inform the backend of the appropriate details for those. Switch to |
|
* Initialised state. |
|
*/ |
|
static int blkfront_probe(struct xenbus_device *dev, |
|
const struct xenbus_device_id *id) |
|
{ |
|
int err, vdevice; |
|
struct blkfront_info *info; |
|
|
|
/* FIXME: Use dynamic device id if this is not set. */ |
|
err = xenbus_scanf(XBT_NIL, dev->nodename, |
|
"virtual-device", "%i", &vdevice); |
|
if (err != 1) { |
|
/* go looking in the extended area instead */ |
|
err = xenbus_scanf(XBT_NIL, dev->nodename, "virtual-device-ext", |
|
"%i", &vdevice); |
|
if (err != 1) { |
|
xenbus_dev_fatal(dev, err, "reading virtual-device"); |
|
return err; |
|
} |
|
} |
|
|
|
if (xen_hvm_domain()) { |
|
char *type; |
|
int len; |
|
/* no unplug has been done: do not hook devices != xen vbds */ |
|
if (xen_has_pv_and_legacy_disk_devices()) { |
|
int major; |
|
|
|
if (!VDEV_IS_EXTENDED(vdevice)) |
|
major = BLKIF_MAJOR(vdevice); |
|
else |
|
major = XENVBD_MAJOR; |
|
|
|
if (major != XENVBD_MAJOR) { |
|
printk(KERN_INFO |
|
"%s: HVM does not support vbd %d as xen block device\n", |
|
__func__, vdevice); |
|
return -ENODEV; |
|
} |
|
} |
|
/* do not create a PV cdrom device if we are an HVM guest */ |
|
type = xenbus_read(XBT_NIL, dev->nodename, "device-type", &len); |
|
if (IS_ERR(type)) |
|
return -ENODEV; |
|
if (strncmp(type, "cdrom", 5) == 0) { |
|
kfree(type); |
|
return -ENODEV; |
|
} |
|
kfree(type); |
|
} |
|
info = kzalloc(sizeof(*info), GFP_KERNEL); |
|
if (!info) { |
|
xenbus_dev_fatal(dev, -ENOMEM, "allocating info structure"); |
|
return -ENOMEM; |
|
} |
|
|
|
info->xbdev = dev; |
|
|
|
mutex_init(&info->mutex); |
|
info->vdevice = vdevice; |
|
info->connected = BLKIF_STATE_DISCONNECTED; |
|
|
|
info->feature_persistent = feature_persistent; |
|
|
|
/* Front end dir is a number, which is used as the id. */ |
|
info->handle = simple_strtoul(strrchr(dev->nodename, '/')+1, NULL, 0); |
|
dev_set_drvdata(&dev->dev, info); |
|
|
|
mutex_lock(&blkfront_mutex); |
|
list_add(&info->info_list, &info_list); |
|
mutex_unlock(&blkfront_mutex); |
|
|
|
return 0; |
|
} |
|
|
|
static int blkif_recover(struct blkfront_info *info) |
|
{ |
|
unsigned int r_index; |
|
struct request *req, *n; |
|
int rc; |
|
struct bio *bio; |
|
unsigned int segs; |
|
struct blkfront_ring_info *rinfo; |
|
|
|
blkfront_gather_backend_features(info); |
|
/* Reset limits changed by blk_mq_update_nr_hw_queues(). */ |
|
blkif_set_queue_limits(info); |
|
segs = info->max_indirect_segments ? : BLKIF_MAX_SEGMENTS_PER_REQUEST; |
|
blk_queue_max_segments(info->rq, segs / GRANTS_PER_PSEG); |
|
|
|
for_each_rinfo(info, rinfo, r_index) { |
|
rc = blkfront_setup_indirect(rinfo); |
|
if (rc) |
|
return rc; |
|
} |
|
xenbus_switch_state(info->xbdev, XenbusStateConnected); |
|
|
|
/* Now safe for us to use the shared ring */ |
|
info->connected = BLKIF_STATE_CONNECTED; |
|
|
|
for_each_rinfo(info, rinfo, r_index) { |
|
/* Kick any other new requests queued since we resumed */ |
|
kick_pending_request_queues(rinfo); |
|
} |
|
|
|
list_for_each_entry_safe(req, n, &info->requests, queuelist) { |
|
/* Requeue pending requests (flush or discard) */ |
|
list_del_init(&req->queuelist); |
|
BUG_ON(req->nr_phys_segments > segs); |
|
blk_mq_requeue_request(req, false); |
|
} |
|
blk_mq_start_stopped_hw_queues(info->rq, true); |
|
blk_mq_kick_requeue_list(info->rq); |
|
|
|
while ((bio = bio_list_pop(&info->bio_list)) != NULL) { |
|
/* Traverse the list of pending bios and re-queue them */ |
|
submit_bio(bio); |
|
} |
|
|
|
return 0; |
|
} |
|
|
|
/* |
|
* We are reconnecting to the backend, due to a suspend/resume, or a backend |
|
* driver restart. We tear down our blkif structure and recreate it, but |
|
* leave the device-layer structures intact so that this is transparent to the |
|
* rest of the kernel. |
|
*/ |
|
static int blkfront_resume(struct xenbus_device *dev) |
|
{ |
|
struct blkfront_info *info = dev_get_drvdata(&dev->dev); |
|
int err = 0; |
|
unsigned int i, j; |
|
struct blkfront_ring_info *rinfo; |
|
|
|
dev_dbg(&dev->dev, "blkfront_resume: %s\n", dev->nodename); |
|
|
|
bio_list_init(&info->bio_list); |
|
INIT_LIST_HEAD(&info->requests); |
|
for_each_rinfo(info, rinfo, i) { |
|
struct bio_list merge_bio; |
|
struct blk_shadow *shadow = rinfo->shadow; |
|
|
|
for (j = 0; j < BLK_RING_SIZE(info); j++) { |
|
/* Not in use? */ |
|
if (!shadow[j].request) |
|
continue; |
|
|
|
/* |
|
* Get the bios in the request so we can re-queue them. |
|
*/ |
|
if (req_op(shadow[j].request) == REQ_OP_FLUSH || |
|
req_op(shadow[j].request) == REQ_OP_DISCARD || |
|
req_op(shadow[j].request) == REQ_OP_SECURE_ERASE || |
|
shadow[j].request->cmd_flags & REQ_FUA) { |
|
/* |
|
* Flush operations don't contain bios, so |
|
* we need to requeue the whole request |
|
* |
|
* XXX: but this doesn't make any sense for a |
|
* write with the FUA flag set.. |
|
*/ |
|
list_add(&shadow[j].request->queuelist, &info->requests); |
|
continue; |
|
} |
|
merge_bio.head = shadow[j].request->bio; |
|
merge_bio.tail = shadow[j].request->biotail; |
|
bio_list_merge(&info->bio_list, &merge_bio); |
|
shadow[j].request->bio = NULL; |
|
blk_mq_end_request(shadow[j].request, BLK_STS_OK); |
|
} |
|
} |
|
|
|
blkif_free(info, info->connected == BLKIF_STATE_CONNECTED); |
|
|
|
err = talk_to_blkback(dev, info); |
|
if (!err) |
|
blk_mq_update_nr_hw_queues(&info->tag_set, info->nr_rings); |
|
|
|
/* |
|
* We have to wait for the backend to switch to |
|
* connected state, since we want to read which |
|
* features it supports. |
|
*/ |
|
|
|
return err; |
|
} |
|
|
|
static void blkfront_closing(struct blkfront_info *info) |
|
{ |
|
struct xenbus_device *xbdev = info->xbdev; |
|
struct blkfront_ring_info *rinfo; |
|
unsigned int i; |
|
|
|
if (xbdev->state == XenbusStateClosing) |
|
return; |
|
|
|
/* No more blkif_request(). */ |
|
blk_mq_stop_hw_queues(info->rq); |
|
blk_mark_disk_dead(info->gd); |
|
set_capacity(info->gd, 0); |
|
|
|
for_each_rinfo(info, rinfo, i) { |
|
/* No more gnttab callback work. */ |
|
gnttab_cancel_free_callback(&rinfo->callback); |
|
|
|
/* Flush gnttab callback work. Must be done with no locks held. */ |
|
flush_work(&rinfo->work); |
|
} |
|
|
|
xenbus_frontend_closed(xbdev); |
|
} |
|
|
|
static void blkfront_setup_discard(struct blkfront_info *info) |
|
{ |
|
info->feature_discard = 1; |
|
info->discard_granularity = xenbus_read_unsigned(info->xbdev->otherend, |
|
"discard-granularity", |
|
0); |
|
info->discard_alignment = xenbus_read_unsigned(info->xbdev->otherend, |
|
"discard-alignment", 0); |
|
info->feature_secdiscard = |
|
!!xenbus_read_unsigned(info->xbdev->otherend, "discard-secure", |
|
0); |
|
} |
|
|
|
static int blkfront_setup_indirect(struct blkfront_ring_info *rinfo) |
|
{ |
|
unsigned int psegs, grants, memflags; |
|
int err, i; |
|
struct blkfront_info *info = rinfo->dev_info; |
|
|
|
memflags = memalloc_noio_save(); |
|
|
|
if (info->max_indirect_segments == 0) { |
|
if (!HAS_EXTRA_REQ) |
|
grants = BLKIF_MAX_SEGMENTS_PER_REQUEST; |
|
else { |
|
/* |
|
* When an extra req is required, the maximum |
|
* grants supported is related to the size of the |
|
* Linux block segment. |
|
*/ |
|
grants = GRANTS_PER_PSEG; |
|
} |
|
} |
|
else |
|
grants = info->max_indirect_segments; |
|
psegs = DIV_ROUND_UP(grants, GRANTS_PER_PSEG); |
|
|
|
err = fill_grant_buffer(rinfo, |
|
(grants + INDIRECT_GREFS(grants)) * BLK_RING_SIZE(info)); |
|
if (err) |
|
goto out_of_memory; |
|
|
|
if (!info->feature_persistent && info->max_indirect_segments) { |
|
/* |
|
* We are using indirect descriptors but not persistent |
|
* grants, we need to allocate a set of pages that can be |
|
* used for mapping indirect grefs |
|
*/ |
|
int num = INDIRECT_GREFS(grants) * BLK_RING_SIZE(info); |
|
|
|
BUG_ON(!list_empty(&rinfo->indirect_pages)); |
|
for (i = 0; i < num; i++) { |
|
struct page *indirect_page = alloc_page(GFP_KERNEL); |
|
if (!indirect_page) |
|
goto out_of_memory; |
|
list_add(&indirect_page->lru, &rinfo->indirect_pages); |
|
} |
|
} |
|
|
|
for (i = 0; i < BLK_RING_SIZE(info); i++) { |
|
rinfo->shadow[i].grants_used = |
|
kvcalloc(grants, |
|
sizeof(rinfo->shadow[i].grants_used[0]), |
|
GFP_KERNEL); |
|
rinfo->shadow[i].sg = kvcalloc(psegs, |
|
sizeof(rinfo->shadow[i].sg[0]), |
|
GFP_KERNEL); |
|
if (info->max_indirect_segments) |
|
rinfo->shadow[i].indirect_grants = |
|
kvcalloc(INDIRECT_GREFS(grants), |
|
sizeof(rinfo->shadow[i].indirect_grants[0]), |
|
GFP_KERNEL); |
|
if ((rinfo->shadow[i].grants_used == NULL) || |
|
(rinfo->shadow[i].sg == NULL) || |
|
(info->max_indirect_segments && |
|
(rinfo->shadow[i].indirect_grants == NULL))) |
|
goto out_of_memory; |
|
sg_init_table(rinfo->shadow[i].sg, psegs); |
|
} |
|
|
|
memalloc_noio_restore(memflags); |
|
|
|
return 0; |
|
|
|
out_of_memory: |
|
for (i = 0; i < BLK_RING_SIZE(info); i++) { |
|
kvfree(rinfo->shadow[i].grants_used); |
|
rinfo->shadow[i].grants_used = NULL; |
|
kvfree(rinfo->shadow[i].sg); |
|
rinfo->shadow[i].sg = NULL; |
|
kvfree(rinfo->shadow[i].indirect_grants); |
|
rinfo->shadow[i].indirect_grants = NULL; |
|
} |
|
if (!list_empty(&rinfo->indirect_pages)) { |
|
struct page *indirect_page, *n; |
|
list_for_each_entry_safe(indirect_page, n, &rinfo->indirect_pages, lru) { |
|
list_del(&indirect_page->lru); |
|
__free_page(indirect_page); |
|
} |
|
} |
|
|
|
memalloc_noio_restore(memflags); |
|
|
|
return -ENOMEM; |
|
} |
|
|
|
/* |
|
* Gather all backend feature-* |
|
*/ |
|
static void blkfront_gather_backend_features(struct blkfront_info *info) |
|
{ |
|
unsigned int indirect_segments; |
|
|
|
info->feature_flush = 0; |
|
info->feature_fua = 0; |
|
|
|
/* |
|
* If there's no "feature-barrier" defined, then it means |
|
* we're dealing with a very old backend which writes |
|
* synchronously; nothing to do. |
|
* |
|
* If there are barriers, then we use flush. |
|
*/ |
|
if (xenbus_read_unsigned(info->xbdev->otherend, "feature-barrier", 0)) { |
|
info->feature_flush = 1; |
|
info->feature_fua = 1; |
|
} |
|
|
|
/* |
|
* And if there is "feature-flush-cache" use that above |
|
* barriers. |
|
*/ |
|
if (xenbus_read_unsigned(info->xbdev->otherend, "feature-flush-cache", |
|
0)) { |
|
info->feature_flush = 1; |
|
info->feature_fua = 0; |
|
} |
|
|
|
if (xenbus_read_unsigned(info->xbdev->otherend, "feature-discard", 0)) |
|
blkfront_setup_discard(info); |
|
|
|
if (info->feature_persistent) |
|
info->feature_persistent = |
|
!!xenbus_read_unsigned(info->xbdev->otherend, |
|
"feature-persistent", 0); |
|
|
|
indirect_segments = xenbus_read_unsigned(info->xbdev->otherend, |
|
"feature-max-indirect-segments", 0); |
|
if (indirect_segments > xen_blkif_max_segments) |
|
indirect_segments = xen_blkif_max_segments; |
|
if (indirect_segments <= BLKIF_MAX_SEGMENTS_PER_REQUEST) |
|
indirect_segments = 0; |
|
info->max_indirect_segments = indirect_segments; |
|
|
|
if (info->feature_persistent) { |
|
mutex_lock(&blkfront_mutex); |
|
schedule_delayed_work(&blkfront_work, HZ * 10); |
|
mutex_unlock(&blkfront_mutex); |
|
} |
|
} |
|
|
|
/* |
|
* Invoked when the backend is finally 'ready' (and has told produced |
|
* the details about the physical device - #sectors, size, etc). |
|
*/ |
|
static void blkfront_connect(struct blkfront_info *info) |
|
{ |
|
unsigned long long sectors; |
|
unsigned long sector_size; |
|
unsigned int physical_sector_size; |
|
int err, i; |
|
struct blkfront_ring_info *rinfo; |
|
|
|
switch (info->connected) { |
|
case BLKIF_STATE_CONNECTED: |
|
/* |
|
* Potentially, the back-end may be signalling |
|
* a capacity change; update the capacity. |
|
*/ |
|
err = xenbus_scanf(XBT_NIL, info->xbdev->otherend, |
|
"sectors", "%Lu", §ors); |
|
if (XENBUS_EXIST_ERR(err)) |
|
return; |
|
printk(KERN_INFO "Setting capacity to %Lu\n", |
|
sectors); |
|
set_capacity_and_notify(info->gd, sectors); |
|
|
|
return; |
|
case BLKIF_STATE_SUSPENDED: |
|
/* |
|
* If we are recovering from suspension, we need to wait |
|
* for the backend to announce it's features before |
|
* reconnecting, at least we need to know if the backend |
|
* supports indirect descriptors, and how many. |
|
*/ |
|
blkif_recover(info); |
|
return; |
|
|
|
default: |
|
break; |
|
} |
|
|
|
dev_dbg(&info->xbdev->dev, "%s:%s.\n", |
|
__func__, info->xbdev->otherend); |
|
|
|
err = xenbus_gather(XBT_NIL, info->xbdev->otherend, |
|
"sectors", "%llu", §ors, |
|
"info", "%u", &info->vdisk_info, |
|
"sector-size", "%lu", §or_size, |
|
NULL); |
|
if (err) { |
|
xenbus_dev_fatal(info->xbdev, err, |
|
"reading backend fields at %s", |
|
info->xbdev->otherend); |
|
return; |
|
} |
|
|
|
/* |
|
* physical-sector-size is a newer field, so old backends may not |
|
* provide this. Assume physical sector size to be the same as |
|
* sector_size in that case. |
|
*/ |
|
physical_sector_size = xenbus_read_unsigned(info->xbdev->otherend, |
|
"physical-sector-size", |
|
sector_size); |
|
blkfront_gather_backend_features(info); |
|
for_each_rinfo(info, rinfo, i) { |
|
err = blkfront_setup_indirect(rinfo); |
|
if (err) { |
|
xenbus_dev_fatal(info->xbdev, err, "setup_indirect at %s", |
|
info->xbdev->otherend); |
|
blkif_free(info, 0); |
|
break; |
|
} |
|
} |
|
|
|
err = xlvbd_alloc_gendisk(sectors, info, sector_size, |
|
physical_sector_size); |
|
if (err) { |
|
xenbus_dev_fatal(info->xbdev, err, "xlvbd_add at %s", |
|
info->xbdev->otherend); |
|
goto fail; |
|
} |
|
|
|
xenbus_switch_state(info->xbdev, XenbusStateConnected); |
|
|
|
/* Kick pending requests. */ |
|
info->connected = BLKIF_STATE_CONNECTED; |
|
for_each_rinfo(info, rinfo, i) |
|
kick_pending_request_queues(rinfo); |
|
|
|
err = device_add_disk(&info->xbdev->dev, info->gd, NULL); |
|
if (err) { |
|
blk_cleanup_disk(info->gd); |
|
blk_mq_free_tag_set(&info->tag_set); |
|
info->rq = NULL; |
|
goto fail; |
|
} |
|
|
|
info->is_ready = 1; |
|
return; |
|
|
|
fail: |
|
blkif_free(info, 0); |
|
return; |
|
} |
|
|
|
/* |
|
* Callback received when the backend's state changes. |
|
*/ |
|
static void blkback_changed(struct xenbus_device *dev, |
|
enum xenbus_state backend_state) |
|
{ |
|
struct blkfront_info *info = dev_get_drvdata(&dev->dev); |
|
|
|
dev_dbg(&dev->dev, "blkfront:blkback_changed to state %d.\n", backend_state); |
|
|
|
switch (backend_state) { |
|
case XenbusStateInitWait: |
|
if (dev->state != XenbusStateInitialising) |
|
break; |
|
if (talk_to_blkback(dev, info)) |
|
break; |
|
break; |
|
case XenbusStateInitialising: |
|
case XenbusStateInitialised: |
|
case XenbusStateReconfiguring: |
|
case XenbusStateReconfigured: |
|
case XenbusStateUnknown: |
|
break; |
|
|
|
case XenbusStateConnected: |
|
/* |
|
* talk_to_blkback sets state to XenbusStateInitialised |
|
* and blkfront_connect sets it to XenbusStateConnected |
|
* (if connection went OK). |
|
* |
|
* If the backend (or toolstack) decides to poke at backend |
|
* state (and re-trigger the watch by setting the state repeatedly |
|
* to XenbusStateConnected (4)) we need to deal with this. |
|
* This is allowed as this is used to communicate to the guest |
|
* that the size of disk has changed! |
|
*/ |
|
if ((dev->state != XenbusStateInitialised) && |
|
(dev->state != XenbusStateConnected)) { |
|
if (talk_to_blkback(dev, info)) |
|
break; |
|
} |
|
|
|
blkfront_connect(info); |
|
break; |
|
|
|
case XenbusStateClosed: |
|
if (dev->state == XenbusStateClosed) |
|
break; |
|
fallthrough; |
|
case XenbusStateClosing: |
|
blkfront_closing(info); |
|
break; |
|
} |
|
} |
|
|
|
static int blkfront_remove(struct xenbus_device *xbdev) |
|
{ |
|
struct blkfront_info *info = dev_get_drvdata(&xbdev->dev); |
|
|
|
dev_dbg(&xbdev->dev, "%s removed", xbdev->nodename); |
|
|
|
del_gendisk(info->gd); |
|
|
|
mutex_lock(&blkfront_mutex); |
|
list_del(&info->info_list); |
|
mutex_unlock(&blkfront_mutex); |
|
|
|
blkif_free(info, 0); |
|
xlbd_release_minors(info->gd->first_minor, info->gd->minors); |
|
blk_cleanup_disk(info->gd); |
|
blk_mq_free_tag_set(&info->tag_set); |
|
|
|
kfree(info); |
|
return 0; |
|
} |
|
|
|
static int blkfront_is_ready(struct xenbus_device *dev) |
|
{ |
|
struct blkfront_info *info = dev_get_drvdata(&dev->dev); |
|
|
|
return info->is_ready && info->xbdev; |
|
} |
|
|
|
static const struct block_device_operations xlvbd_block_fops = |
|
{ |
|
.owner = THIS_MODULE, |
|
.getgeo = blkif_getgeo, |
|
.ioctl = blkif_ioctl, |
|
.compat_ioctl = blkdev_compat_ptr_ioctl, |
|
}; |
|
|
|
|
|
static const struct xenbus_device_id blkfront_ids[] = { |
|
{ "vbd" }, |
|
{ "" } |
|
}; |
|
|
|
static struct xenbus_driver blkfront_driver = { |
|
.ids = blkfront_ids, |
|
.probe = blkfront_probe, |
|
.remove = blkfront_remove, |
|
.resume = blkfront_resume, |
|
.otherend_changed = blkback_changed, |
|
.is_ready = blkfront_is_ready, |
|
}; |
|
|
|
static void purge_persistent_grants(struct blkfront_info *info) |
|
{ |
|
unsigned int i; |
|
unsigned long flags; |
|
struct blkfront_ring_info *rinfo; |
|
|
|
for_each_rinfo(info, rinfo, i) { |
|
struct grant *gnt_list_entry, *tmp; |
|
|
|
spin_lock_irqsave(&rinfo->ring_lock, flags); |
|
|
|
if (rinfo->persistent_gnts_c == 0) { |
|
spin_unlock_irqrestore(&rinfo->ring_lock, flags); |
|
continue; |
|
} |
|
|
|
list_for_each_entry_safe(gnt_list_entry, tmp, &rinfo->grants, |
|
node) { |
|
if (gnt_list_entry->gref == GRANT_INVALID_REF || |
|
!gnttab_try_end_foreign_access(gnt_list_entry->gref)) |
|
continue; |
|
|
|
list_del(&gnt_list_entry->node); |
|
rinfo->persistent_gnts_c--; |
|
gnt_list_entry->gref = GRANT_INVALID_REF; |
|
list_add_tail(&gnt_list_entry->node, &rinfo->grants); |
|
} |
|
|
|
spin_unlock_irqrestore(&rinfo->ring_lock, flags); |
|
} |
|
} |
|
|
|
static void blkfront_delay_work(struct work_struct *work) |
|
{ |
|
struct blkfront_info *info; |
|
bool need_schedule_work = false; |
|
|
|
mutex_lock(&blkfront_mutex); |
|
|
|
list_for_each_entry(info, &info_list, info_list) { |
|
if (info->feature_persistent) { |
|
need_schedule_work = true; |
|
mutex_lock(&info->mutex); |
|
purge_persistent_grants(info); |
|
mutex_unlock(&info->mutex); |
|
} |
|
} |
|
|
|
if (need_schedule_work) |
|
schedule_delayed_work(&blkfront_work, HZ * 10); |
|
|
|
mutex_unlock(&blkfront_mutex); |
|
} |
|
|
|
static int __init xlblk_init(void) |
|
{ |
|
int ret; |
|
int nr_cpus = num_online_cpus(); |
|
|
|
if (!xen_domain()) |
|
return -ENODEV; |
|
|
|
if (!xen_has_pv_disk_devices()) |
|
return -ENODEV; |
|
|
|
if (register_blkdev(XENVBD_MAJOR, DEV_NAME)) { |
|
pr_warn("xen_blk: can't get major %d with name %s\n", |
|
XENVBD_MAJOR, DEV_NAME); |
|
return -ENODEV; |
|
} |
|
|
|
if (xen_blkif_max_segments < BLKIF_MAX_SEGMENTS_PER_REQUEST) |
|
xen_blkif_max_segments = BLKIF_MAX_SEGMENTS_PER_REQUEST; |
|
|
|
if (xen_blkif_max_ring_order > XENBUS_MAX_RING_GRANT_ORDER) { |
|
pr_info("Invalid max_ring_order (%d), will use default max: %d.\n", |
|
xen_blkif_max_ring_order, XENBUS_MAX_RING_GRANT_ORDER); |
|
xen_blkif_max_ring_order = XENBUS_MAX_RING_GRANT_ORDER; |
|
} |
|
|
|
if (xen_blkif_max_queues > nr_cpus) { |
|
pr_info("Invalid max_queues (%d), will use default max: %d.\n", |
|
xen_blkif_max_queues, nr_cpus); |
|
xen_blkif_max_queues = nr_cpus; |
|
} |
|
|
|
INIT_DELAYED_WORK(&blkfront_work, blkfront_delay_work); |
|
|
|
ret = xenbus_register_frontend(&blkfront_driver); |
|
if (ret) { |
|
unregister_blkdev(XENVBD_MAJOR, DEV_NAME); |
|
return ret; |
|
} |
|
|
|
return 0; |
|
} |
|
module_init(xlblk_init); |
|
|
|
|
|
static void __exit xlblk_exit(void) |
|
{ |
|
cancel_delayed_work_sync(&blkfront_work); |
|
|
|
xenbus_unregister_driver(&blkfront_driver); |
|
unregister_blkdev(XENVBD_MAJOR, DEV_NAME); |
|
kfree(minors); |
|
} |
|
module_exit(xlblk_exit); |
|
|
|
MODULE_DESCRIPTION("Xen virtual block device frontend"); |
|
MODULE_LICENSE("GPL"); |
|
MODULE_ALIAS_BLOCKDEV_MAJOR(XENVBD_MAJOR); |
|
MODULE_ALIAS("xen:vbd"); |
|
MODULE_ALIAS("xenblk");
|
|
|