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1477 lines
41 KiB
1477 lines
41 KiB
/****************************************************************************** |
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* |
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* Back-end of the driver for virtual block devices. This portion of the |
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* driver exports a 'unified' block-device interface that can be accessed |
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* by any operating system that implements a compatible front end. A |
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* reference front-end implementation can be found in: |
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* drivers/block/xen-blkfront.c |
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* |
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* Copyright (c) 2003-2004, Keir Fraser & Steve Hand |
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* Copyright (c) 2005, Christopher Clark |
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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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#define pr_fmt(fmt) "xen-blkback: " fmt |
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|
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#include <linux/spinlock.h> |
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#include <linux/kthread.h> |
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#include <linux/list.h> |
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#include <linux/delay.h> |
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#include <linux/freezer.h> |
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#include <linux/bitmap.h> |
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|
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#include <xen/events.h> |
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#include <xen/page.h> |
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#include <xen/xen.h> |
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#include <asm/xen/hypervisor.h> |
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#include <asm/xen/hypercall.h> |
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#include <xen/balloon.h> |
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#include <xen/grant_table.h> |
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#include "common.h" |
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|
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/* |
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* Maximum number of unused free pages to keep in the internal buffer. |
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* Setting this to a value too low will reduce memory used in each backend, |
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* but can have a performance penalty. |
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* |
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* A sane value is xen_blkif_reqs * BLKIF_MAX_SEGMENTS_PER_REQUEST, but can |
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* be set to a lower value that might degrade performance on some intensive |
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* IO workloads. |
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*/ |
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|
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static int max_buffer_pages = 1024; |
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module_param_named(max_buffer_pages, max_buffer_pages, int, 0644); |
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MODULE_PARM_DESC(max_buffer_pages, |
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"Maximum number of free pages to keep in each block backend buffer"); |
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|
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/* |
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* Maximum number of grants to map persistently in blkback. For maximum |
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* performance this should be the total numbers of grants that can be used |
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* to fill the ring, but since this might become too high, specially with |
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* the use of indirect descriptors, we set it to a value that provides good |
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* performance without using too much memory. |
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* |
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* When the list of persistent grants is full we clean it up using a LRU |
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* algorithm. |
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*/ |
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|
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static int max_pgrants = 1056; |
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module_param_named(max_persistent_grants, max_pgrants, int, 0644); |
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MODULE_PARM_DESC(max_persistent_grants, |
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"Maximum number of grants to map persistently"); |
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|
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/* |
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* How long a persistent grant is allowed to remain allocated without being in |
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* use. The time is in seconds, 0 means indefinitely long. |
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*/ |
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|
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static unsigned int pgrant_timeout = 60; |
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module_param_named(persistent_grant_unused_seconds, pgrant_timeout, |
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uint, 0644); |
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MODULE_PARM_DESC(persistent_grant_unused_seconds, |
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"Time in seconds an unused persistent grant is allowed to " |
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"remain allocated. Default is 60, 0 means unlimited."); |
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|
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/* |
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* Maximum number of rings/queues blkback supports, allow as many queues as there |
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* are CPUs if user has not specified a value. |
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*/ |
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unsigned int xenblk_max_queues; |
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module_param_named(max_queues, xenblk_max_queues, uint, 0644); |
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MODULE_PARM_DESC(max_queues, |
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"Maximum number of hardware queues per virtual disk." \ |
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"By default it is the number of online CPUs."); |
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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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unsigned int xen_blkif_max_ring_order = XENBUS_MAX_RING_GRANT_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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* The LRU mechanism to clean the lists of persistent grants needs to |
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* be executed periodically. The time interval between consecutive executions |
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* of the purge mechanism is set in ms. |
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*/ |
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#define LRU_INTERVAL 100 |
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|
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/* |
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* When the persistent grants list is full we will remove unused grants |
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* from the list. The percent number of grants to be removed at each LRU |
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* execution. |
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*/ |
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#define LRU_PERCENT_CLEAN 5 |
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|
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/* Run-time switchable: /sys/module/blkback/parameters/ */ |
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static unsigned int log_stats; |
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module_param(log_stats, int, 0644); |
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|
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#define BLKBACK_INVALID_HANDLE (~0) |
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|
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static inline bool persistent_gnt_timeout(struct persistent_gnt *persistent_gnt) |
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{ |
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return pgrant_timeout && (jiffies - persistent_gnt->last_used >= |
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HZ * pgrant_timeout); |
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} |
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|
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#define vaddr(page) ((unsigned long)pfn_to_kaddr(page_to_pfn(page))) |
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|
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static int do_block_io_op(struct xen_blkif_ring *ring, unsigned int *eoi_flags); |
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static int dispatch_rw_block_io(struct xen_blkif_ring *ring, |
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struct blkif_request *req, |
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struct pending_req *pending_req); |
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static void make_response(struct xen_blkif_ring *ring, u64 id, |
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unsigned short op, int st); |
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|
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#define foreach_grant_safe(pos, n, rbtree, node) \ |
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for ((pos) = container_of(rb_first((rbtree)), typeof(*(pos)), node), \ |
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(n) = (&(pos)->node != NULL) ? rb_next(&(pos)->node) : NULL; \ |
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&(pos)->node != NULL; \ |
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(pos) = container_of(n, typeof(*(pos)), node), \ |
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(n) = (&(pos)->node != NULL) ? rb_next(&(pos)->node) : NULL) |
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|
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|
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/* |
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* We don't need locking around the persistent grant helpers |
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* because blkback uses a single-thread for each backend, so we |
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* can be sure that this functions will never be called recursively. |
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* |
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* The only exception to that is put_persistent_grant, that can be called |
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* from interrupt context (by xen_blkbk_unmap), so we have to use atomic |
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* bit operations to modify the flags of a persistent grant and to count |
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* the number of used grants. |
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*/ |
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static int add_persistent_gnt(struct xen_blkif_ring *ring, |
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struct persistent_gnt *persistent_gnt) |
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{ |
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struct rb_node **new = NULL, *parent = NULL; |
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struct persistent_gnt *this; |
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struct xen_blkif *blkif = ring->blkif; |
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|
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if (ring->persistent_gnt_c >= max_pgrants) { |
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if (!blkif->vbd.overflow_max_grants) |
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blkif->vbd.overflow_max_grants = 1; |
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return -EBUSY; |
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} |
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/* Figure out where to put new node */ |
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new = &ring->persistent_gnts.rb_node; |
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while (*new) { |
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this = container_of(*new, struct persistent_gnt, node); |
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|
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parent = *new; |
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if (persistent_gnt->gnt < this->gnt) |
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new = &((*new)->rb_left); |
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else if (persistent_gnt->gnt > this->gnt) |
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new = &((*new)->rb_right); |
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else { |
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pr_alert_ratelimited("trying to add a gref that's already in the tree\n"); |
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return -EINVAL; |
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} |
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} |
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|
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persistent_gnt->active = true; |
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/* Add new node and rebalance tree. */ |
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rb_link_node(&(persistent_gnt->node), parent, new); |
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rb_insert_color(&(persistent_gnt->node), &ring->persistent_gnts); |
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ring->persistent_gnt_c++; |
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atomic_inc(&ring->persistent_gnt_in_use); |
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return 0; |
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} |
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|
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static struct persistent_gnt *get_persistent_gnt(struct xen_blkif_ring *ring, |
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grant_ref_t gref) |
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{ |
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struct persistent_gnt *data; |
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struct rb_node *node = NULL; |
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|
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node = ring->persistent_gnts.rb_node; |
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while (node) { |
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data = container_of(node, struct persistent_gnt, node); |
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|
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if (gref < data->gnt) |
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node = node->rb_left; |
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else if (gref > data->gnt) |
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node = node->rb_right; |
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else { |
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if (data->active) { |
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pr_alert_ratelimited("requesting a grant already in use\n"); |
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return NULL; |
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} |
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data->active = true; |
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atomic_inc(&ring->persistent_gnt_in_use); |
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return data; |
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} |
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} |
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return NULL; |
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} |
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|
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static void put_persistent_gnt(struct xen_blkif_ring *ring, |
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struct persistent_gnt *persistent_gnt) |
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{ |
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if (!persistent_gnt->active) |
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pr_alert_ratelimited("freeing a grant already unused\n"); |
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persistent_gnt->last_used = jiffies; |
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persistent_gnt->active = false; |
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atomic_dec(&ring->persistent_gnt_in_use); |
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} |
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|
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static void free_persistent_gnts(struct xen_blkif_ring *ring, struct rb_root *root, |
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unsigned int num) |
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{ |
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struct gnttab_unmap_grant_ref unmap[BLKIF_MAX_SEGMENTS_PER_REQUEST]; |
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struct page *pages[BLKIF_MAX_SEGMENTS_PER_REQUEST]; |
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struct persistent_gnt *persistent_gnt; |
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struct rb_node *n; |
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int segs_to_unmap = 0; |
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struct gntab_unmap_queue_data unmap_data; |
|
|
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unmap_data.pages = pages; |
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unmap_data.unmap_ops = unmap; |
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unmap_data.kunmap_ops = NULL; |
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|
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foreach_grant_safe(persistent_gnt, n, root, node) { |
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BUG_ON(persistent_gnt->handle == |
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BLKBACK_INVALID_HANDLE); |
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gnttab_set_unmap_op(&unmap[segs_to_unmap], |
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(unsigned long) pfn_to_kaddr(page_to_pfn( |
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persistent_gnt->page)), |
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GNTMAP_host_map, |
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persistent_gnt->handle); |
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|
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pages[segs_to_unmap] = persistent_gnt->page; |
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|
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if (++segs_to_unmap == BLKIF_MAX_SEGMENTS_PER_REQUEST || |
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!rb_next(&persistent_gnt->node)) { |
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|
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unmap_data.count = segs_to_unmap; |
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BUG_ON(gnttab_unmap_refs_sync(&unmap_data)); |
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|
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gnttab_page_cache_put(&ring->free_pages, pages, |
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segs_to_unmap); |
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segs_to_unmap = 0; |
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} |
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|
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rb_erase(&persistent_gnt->node, root); |
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kfree(persistent_gnt); |
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num--; |
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} |
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BUG_ON(num != 0); |
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} |
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|
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void xen_blkbk_unmap_purged_grants(struct work_struct *work) |
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{ |
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struct gnttab_unmap_grant_ref unmap[BLKIF_MAX_SEGMENTS_PER_REQUEST]; |
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struct page *pages[BLKIF_MAX_SEGMENTS_PER_REQUEST]; |
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struct persistent_gnt *persistent_gnt; |
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int segs_to_unmap = 0; |
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struct xen_blkif_ring *ring = container_of(work, typeof(*ring), persistent_purge_work); |
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struct gntab_unmap_queue_data unmap_data; |
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|
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unmap_data.pages = pages; |
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unmap_data.unmap_ops = unmap; |
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unmap_data.kunmap_ops = NULL; |
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|
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while(!list_empty(&ring->persistent_purge_list)) { |
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persistent_gnt = list_first_entry(&ring->persistent_purge_list, |
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struct persistent_gnt, |
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remove_node); |
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list_del(&persistent_gnt->remove_node); |
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|
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gnttab_set_unmap_op(&unmap[segs_to_unmap], |
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vaddr(persistent_gnt->page), |
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GNTMAP_host_map, |
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persistent_gnt->handle); |
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|
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pages[segs_to_unmap] = persistent_gnt->page; |
|
|
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if (++segs_to_unmap == BLKIF_MAX_SEGMENTS_PER_REQUEST) { |
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unmap_data.count = segs_to_unmap; |
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BUG_ON(gnttab_unmap_refs_sync(&unmap_data)); |
|
gnttab_page_cache_put(&ring->free_pages, pages, |
|
segs_to_unmap); |
|
segs_to_unmap = 0; |
|
} |
|
kfree(persistent_gnt); |
|
} |
|
if (segs_to_unmap > 0) { |
|
unmap_data.count = segs_to_unmap; |
|
BUG_ON(gnttab_unmap_refs_sync(&unmap_data)); |
|
gnttab_page_cache_put(&ring->free_pages, pages, segs_to_unmap); |
|
} |
|
} |
|
|
|
static void purge_persistent_gnt(struct xen_blkif_ring *ring) |
|
{ |
|
struct persistent_gnt *persistent_gnt; |
|
struct rb_node *n; |
|
unsigned int num_clean, total; |
|
bool scan_used = false; |
|
struct rb_root *root; |
|
|
|
if (work_busy(&ring->persistent_purge_work)) { |
|
pr_alert_ratelimited("Scheduled work from previous purge is still busy, cannot purge list\n"); |
|
goto out; |
|
} |
|
|
|
if (ring->persistent_gnt_c < max_pgrants || |
|
(ring->persistent_gnt_c == max_pgrants && |
|
!ring->blkif->vbd.overflow_max_grants)) { |
|
num_clean = 0; |
|
} else { |
|
num_clean = (max_pgrants / 100) * LRU_PERCENT_CLEAN; |
|
num_clean = ring->persistent_gnt_c - max_pgrants + num_clean; |
|
num_clean = min(ring->persistent_gnt_c, num_clean); |
|
pr_debug("Going to purge at least %u persistent grants\n", |
|
num_clean); |
|
} |
|
|
|
/* |
|
* At this point, we can assure that there will be no calls |
|
* to get_persistent_grant (because we are executing this code from |
|
* xen_blkif_schedule), there can only be calls to put_persistent_gnt, |
|
* which means that the number of currently used grants will go down, |
|
* but never up, so we will always be able to remove the requested |
|
* number of grants. |
|
*/ |
|
|
|
total = 0; |
|
|
|
BUG_ON(!list_empty(&ring->persistent_purge_list)); |
|
root = &ring->persistent_gnts; |
|
purge_list: |
|
foreach_grant_safe(persistent_gnt, n, root, node) { |
|
BUG_ON(persistent_gnt->handle == |
|
BLKBACK_INVALID_HANDLE); |
|
|
|
if (persistent_gnt->active) |
|
continue; |
|
if (!scan_used && !persistent_gnt_timeout(persistent_gnt)) |
|
continue; |
|
if (scan_used && total >= num_clean) |
|
continue; |
|
|
|
rb_erase(&persistent_gnt->node, root); |
|
list_add(&persistent_gnt->remove_node, |
|
&ring->persistent_purge_list); |
|
total++; |
|
} |
|
/* |
|
* Check whether we also need to start cleaning |
|
* grants that were used since last purge in order to cope |
|
* with the requested num |
|
*/ |
|
if (!scan_used && total < num_clean) { |
|
pr_debug("Still missing %u purged frames\n", num_clean - total); |
|
scan_used = true; |
|
goto purge_list; |
|
} |
|
|
|
if (total) { |
|
ring->persistent_gnt_c -= total; |
|
ring->blkif->vbd.overflow_max_grants = 0; |
|
|
|
/* We can defer this work */ |
|
schedule_work(&ring->persistent_purge_work); |
|
pr_debug("Purged %u/%u\n", num_clean, total); |
|
} |
|
|
|
out: |
|
return; |
|
} |
|
|
|
/* |
|
* Retrieve from the 'pending_reqs' a free pending_req structure to be used. |
|
*/ |
|
static struct pending_req *alloc_req(struct xen_blkif_ring *ring) |
|
{ |
|
struct pending_req *req = NULL; |
|
unsigned long flags; |
|
|
|
spin_lock_irqsave(&ring->pending_free_lock, flags); |
|
if (!list_empty(&ring->pending_free)) { |
|
req = list_entry(ring->pending_free.next, struct pending_req, |
|
free_list); |
|
list_del(&req->free_list); |
|
} |
|
spin_unlock_irqrestore(&ring->pending_free_lock, flags); |
|
return req; |
|
} |
|
|
|
/* |
|
* Return the 'pending_req' structure back to the freepool. We also |
|
* wake up the thread if it was waiting for a free page. |
|
*/ |
|
static void free_req(struct xen_blkif_ring *ring, struct pending_req *req) |
|
{ |
|
unsigned long flags; |
|
int was_empty; |
|
|
|
spin_lock_irqsave(&ring->pending_free_lock, flags); |
|
was_empty = list_empty(&ring->pending_free); |
|
list_add(&req->free_list, &ring->pending_free); |
|
spin_unlock_irqrestore(&ring->pending_free_lock, flags); |
|
if (was_empty) |
|
wake_up(&ring->pending_free_wq); |
|
} |
|
|
|
/* |
|
* Routines for managing virtual block devices (vbds). |
|
*/ |
|
static int xen_vbd_translate(struct phys_req *req, struct xen_blkif *blkif, |
|
int operation) |
|
{ |
|
struct xen_vbd *vbd = &blkif->vbd; |
|
int rc = -EACCES; |
|
|
|
if ((operation != REQ_OP_READ) && vbd->readonly) |
|
goto out; |
|
|
|
if (likely(req->nr_sects)) { |
|
blkif_sector_t end = req->sector_number + req->nr_sects; |
|
|
|
if (unlikely(end < req->sector_number)) |
|
goto out; |
|
if (unlikely(end > vbd_sz(vbd))) |
|
goto out; |
|
} |
|
|
|
req->dev = vbd->pdevice; |
|
req->bdev = vbd->bdev; |
|
rc = 0; |
|
|
|
out: |
|
return rc; |
|
} |
|
|
|
static void xen_vbd_resize(struct xen_blkif *blkif) |
|
{ |
|
struct xen_vbd *vbd = &blkif->vbd; |
|
struct xenbus_transaction xbt; |
|
int err; |
|
struct xenbus_device *dev = xen_blkbk_xenbus(blkif->be); |
|
unsigned long long new_size = vbd_sz(vbd); |
|
|
|
pr_info("VBD Resize: Domid: %d, Device: (%d, %d)\n", |
|
blkif->domid, MAJOR(vbd->pdevice), MINOR(vbd->pdevice)); |
|
pr_info("VBD Resize: new size %llu\n", new_size); |
|
vbd->size = new_size; |
|
again: |
|
err = xenbus_transaction_start(&xbt); |
|
if (err) { |
|
pr_warn("Error starting transaction\n"); |
|
return; |
|
} |
|
err = xenbus_printf(xbt, dev->nodename, "sectors", "%llu", |
|
(unsigned long long)vbd_sz(vbd)); |
|
if (err) { |
|
pr_warn("Error writing new size\n"); |
|
goto abort; |
|
} |
|
/* |
|
* Write the current state; we will use this to synchronize |
|
* the front-end. If the current state is "connected" the |
|
* front-end will get the new size information online. |
|
*/ |
|
err = xenbus_printf(xbt, dev->nodename, "state", "%d", dev->state); |
|
if (err) { |
|
pr_warn("Error writing the state\n"); |
|
goto abort; |
|
} |
|
|
|
err = xenbus_transaction_end(xbt, 0); |
|
if (err == -EAGAIN) |
|
goto again; |
|
if (err) |
|
pr_warn("Error ending transaction\n"); |
|
return; |
|
abort: |
|
xenbus_transaction_end(xbt, 1); |
|
} |
|
|
|
/* |
|
* Notification from the guest OS. |
|
*/ |
|
static void blkif_notify_work(struct xen_blkif_ring *ring) |
|
{ |
|
ring->waiting_reqs = 1; |
|
wake_up(&ring->wq); |
|
} |
|
|
|
irqreturn_t xen_blkif_be_int(int irq, void *dev_id) |
|
{ |
|
blkif_notify_work(dev_id); |
|
return IRQ_HANDLED; |
|
} |
|
|
|
/* |
|
* SCHEDULER FUNCTIONS |
|
*/ |
|
|
|
static void print_stats(struct xen_blkif_ring *ring) |
|
{ |
|
pr_info("(%s): oo %3llu | rd %4llu | wr %4llu | f %4llu" |
|
" | ds %4llu | pg: %4u/%4d\n", |
|
current->comm, ring->st_oo_req, |
|
ring->st_rd_req, ring->st_wr_req, |
|
ring->st_f_req, ring->st_ds_req, |
|
ring->persistent_gnt_c, max_pgrants); |
|
ring->st_print = jiffies + msecs_to_jiffies(10 * 1000); |
|
ring->st_rd_req = 0; |
|
ring->st_wr_req = 0; |
|
ring->st_oo_req = 0; |
|
ring->st_ds_req = 0; |
|
} |
|
|
|
int xen_blkif_schedule(void *arg) |
|
{ |
|
struct xen_blkif_ring *ring = arg; |
|
struct xen_blkif *blkif = ring->blkif; |
|
struct xen_vbd *vbd = &blkif->vbd; |
|
unsigned long timeout; |
|
int ret; |
|
bool do_eoi; |
|
unsigned int eoi_flags = XEN_EOI_FLAG_SPURIOUS; |
|
|
|
set_freezable(); |
|
while (!kthread_should_stop()) { |
|
if (try_to_freeze()) |
|
continue; |
|
if (unlikely(vbd->size != vbd_sz(vbd))) |
|
xen_vbd_resize(blkif); |
|
|
|
timeout = msecs_to_jiffies(LRU_INTERVAL); |
|
|
|
timeout = wait_event_interruptible_timeout( |
|
ring->wq, |
|
ring->waiting_reqs || kthread_should_stop(), |
|
timeout); |
|
if (timeout == 0) |
|
goto purge_gnt_list; |
|
timeout = wait_event_interruptible_timeout( |
|
ring->pending_free_wq, |
|
!list_empty(&ring->pending_free) || |
|
kthread_should_stop(), |
|
timeout); |
|
if (timeout == 0) |
|
goto purge_gnt_list; |
|
|
|
do_eoi = ring->waiting_reqs; |
|
|
|
ring->waiting_reqs = 0; |
|
smp_mb(); /* clear flag *before* checking for work */ |
|
|
|
ret = do_block_io_op(ring, &eoi_flags); |
|
if (ret > 0) |
|
ring->waiting_reqs = 1; |
|
if (ret == -EACCES) |
|
wait_event_interruptible(ring->shutdown_wq, |
|
kthread_should_stop()); |
|
|
|
if (do_eoi && !ring->waiting_reqs) { |
|
xen_irq_lateeoi(ring->irq, eoi_flags); |
|
eoi_flags |= XEN_EOI_FLAG_SPURIOUS; |
|
} |
|
|
|
purge_gnt_list: |
|
if (blkif->vbd.feature_gnt_persistent && |
|
time_after(jiffies, ring->next_lru)) { |
|
purge_persistent_gnt(ring); |
|
ring->next_lru = jiffies + msecs_to_jiffies(LRU_INTERVAL); |
|
} |
|
|
|
/* Shrink the free pages pool if it is too large. */ |
|
if (time_before(jiffies, blkif->buffer_squeeze_end)) |
|
gnttab_page_cache_shrink(&ring->free_pages, 0); |
|
else |
|
gnttab_page_cache_shrink(&ring->free_pages, |
|
max_buffer_pages); |
|
|
|
if (log_stats && time_after(jiffies, ring->st_print)) |
|
print_stats(ring); |
|
} |
|
|
|
/* Drain pending purge work */ |
|
flush_work(&ring->persistent_purge_work); |
|
|
|
if (log_stats) |
|
print_stats(ring); |
|
|
|
ring->xenblkd = NULL; |
|
|
|
return 0; |
|
} |
|
|
|
/* |
|
* Remove persistent grants and empty the pool of free pages |
|
*/ |
|
void xen_blkbk_free_caches(struct xen_blkif_ring *ring) |
|
{ |
|
/* Free all persistent grant pages */ |
|
if (!RB_EMPTY_ROOT(&ring->persistent_gnts)) |
|
free_persistent_gnts(ring, &ring->persistent_gnts, |
|
ring->persistent_gnt_c); |
|
|
|
BUG_ON(!RB_EMPTY_ROOT(&ring->persistent_gnts)); |
|
ring->persistent_gnt_c = 0; |
|
|
|
/* Since we are shutting down remove all pages from the buffer */ |
|
gnttab_page_cache_shrink(&ring->free_pages, 0 /* All */); |
|
} |
|
|
|
static unsigned int xen_blkbk_unmap_prepare( |
|
struct xen_blkif_ring *ring, |
|
struct grant_page **pages, |
|
unsigned int num, |
|
struct gnttab_unmap_grant_ref *unmap_ops, |
|
struct page **unmap_pages) |
|
{ |
|
unsigned int i, invcount = 0; |
|
|
|
for (i = 0; i < num; i++) { |
|
if (pages[i]->persistent_gnt != NULL) { |
|
put_persistent_gnt(ring, pages[i]->persistent_gnt); |
|
continue; |
|
} |
|
if (pages[i]->handle == BLKBACK_INVALID_HANDLE) |
|
continue; |
|
unmap_pages[invcount] = pages[i]->page; |
|
gnttab_set_unmap_op(&unmap_ops[invcount], vaddr(pages[i]->page), |
|
GNTMAP_host_map, pages[i]->handle); |
|
pages[i]->handle = BLKBACK_INVALID_HANDLE; |
|
invcount++; |
|
} |
|
|
|
return invcount; |
|
} |
|
|
|
static void xen_blkbk_unmap_and_respond_callback(int result, struct gntab_unmap_queue_data *data) |
|
{ |
|
struct pending_req *pending_req = (struct pending_req *)(data->data); |
|
struct xen_blkif_ring *ring = pending_req->ring; |
|
struct xen_blkif *blkif = ring->blkif; |
|
|
|
/* BUG_ON used to reproduce existing behaviour, |
|
but is this the best way to deal with this? */ |
|
BUG_ON(result); |
|
|
|
gnttab_page_cache_put(&ring->free_pages, data->pages, data->count); |
|
make_response(ring, pending_req->id, |
|
pending_req->operation, pending_req->status); |
|
free_req(ring, pending_req); |
|
/* |
|
* Make sure the request is freed before releasing blkif, |
|
* or there could be a race between free_req and the |
|
* cleanup done in xen_blkif_free during shutdown. |
|
* |
|
* NB: The fact that we might try to wake up pending_free_wq |
|
* before drain_complete (in case there's a drain going on) |
|
* it's not a problem with our current implementation |
|
* because we can assure there's no thread waiting on |
|
* pending_free_wq if there's a drain going on, but it has |
|
* to be taken into account if the current model is changed. |
|
*/ |
|
if (atomic_dec_and_test(&ring->inflight) && atomic_read(&blkif->drain)) { |
|
complete(&blkif->drain_complete); |
|
} |
|
xen_blkif_put(blkif); |
|
} |
|
|
|
static void xen_blkbk_unmap_and_respond(struct pending_req *req) |
|
{ |
|
struct gntab_unmap_queue_data* work = &req->gnttab_unmap_data; |
|
struct xen_blkif_ring *ring = req->ring; |
|
struct grant_page **pages = req->segments; |
|
unsigned int invcount; |
|
|
|
invcount = xen_blkbk_unmap_prepare(ring, pages, req->nr_segs, |
|
req->unmap, req->unmap_pages); |
|
|
|
work->data = req; |
|
work->done = xen_blkbk_unmap_and_respond_callback; |
|
work->unmap_ops = req->unmap; |
|
work->kunmap_ops = NULL; |
|
work->pages = req->unmap_pages; |
|
work->count = invcount; |
|
|
|
gnttab_unmap_refs_async(&req->gnttab_unmap_data); |
|
} |
|
|
|
|
|
/* |
|
* Unmap the grant references. |
|
* |
|
* This could accumulate ops up to the batch size to reduce the number |
|
* of hypercalls, but since this is only used in error paths there's |
|
* no real need. |
|
*/ |
|
static void xen_blkbk_unmap(struct xen_blkif_ring *ring, |
|
struct grant_page *pages[], |
|
int num) |
|
{ |
|
struct gnttab_unmap_grant_ref unmap[BLKIF_MAX_SEGMENTS_PER_REQUEST]; |
|
struct page *unmap_pages[BLKIF_MAX_SEGMENTS_PER_REQUEST]; |
|
unsigned int invcount = 0; |
|
int ret; |
|
|
|
while (num) { |
|
unsigned int batch = min(num, BLKIF_MAX_SEGMENTS_PER_REQUEST); |
|
|
|
invcount = xen_blkbk_unmap_prepare(ring, pages, batch, |
|
unmap, unmap_pages); |
|
if (invcount) { |
|
ret = gnttab_unmap_refs(unmap, NULL, unmap_pages, invcount); |
|
BUG_ON(ret); |
|
gnttab_page_cache_put(&ring->free_pages, unmap_pages, |
|
invcount); |
|
} |
|
pages += batch; |
|
num -= batch; |
|
} |
|
} |
|
|
|
static int xen_blkbk_map(struct xen_blkif_ring *ring, |
|
struct grant_page *pages[], |
|
int num, bool ro) |
|
{ |
|
struct gnttab_map_grant_ref map[BLKIF_MAX_SEGMENTS_PER_REQUEST]; |
|
struct page *pages_to_gnt[BLKIF_MAX_SEGMENTS_PER_REQUEST]; |
|
struct persistent_gnt *persistent_gnt = NULL; |
|
phys_addr_t addr = 0; |
|
int i, seg_idx, new_map_idx; |
|
int segs_to_map = 0; |
|
int ret = 0; |
|
int last_map = 0, map_until = 0; |
|
int use_persistent_gnts; |
|
struct xen_blkif *blkif = ring->blkif; |
|
|
|
use_persistent_gnts = (blkif->vbd.feature_gnt_persistent); |
|
|
|
/* |
|
* Fill out preq.nr_sects with proper amount of sectors, and setup |
|
* assign map[..] with the PFN of the page in our domain with the |
|
* corresponding grant reference for each page. |
|
*/ |
|
again: |
|
for (i = map_until; i < num; i++) { |
|
uint32_t flags; |
|
|
|
if (use_persistent_gnts) { |
|
persistent_gnt = get_persistent_gnt( |
|
ring, |
|
pages[i]->gref); |
|
} |
|
|
|
if (persistent_gnt) { |
|
/* |
|
* We are using persistent grants and |
|
* the grant is already mapped |
|
*/ |
|
pages[i]->page = persistent_gnt->page; |
|
pages[i]->persistent_gnt = persistent_gnt; |
|
} else { |
|
if (gnttab_page_cache_get(&ring->free_pages, |
|
&pages[i]->page)) { |
|
gnttab_page_cache_put(&ring->free_pages, |
|
pages_to_gnt, |
|
segs_to_map); |
|
ret = -ENOMEM; |
|
goto out; |
|
} |
|
addr = vaddr(pages[i]->page); |
|
pages_to_gnt[segs_to_map] = pages[i]->page; |
|
pages[i]->persistent_gnt = NULL; |
|
flags = GNTMAP_host_map; |
|
if (!use_persistent_gnts && ro) |
|
flags |= GNTMAP_readonly; |
|
gnttab_set_map_op(&map[segs_to_map++], addr, |
|
flags, pages[i]->gref, |
|
blkif->domid); |
|
} |
|
map_until = i + 1; |
|
if (segs_to_map == BLKIF_MAX_SEGMENTS_PER_REQUEST) |
|
break; |
|
} |
|
|
|
if (segs_to_map) |
|
ret = gnttab_map_refs(map, NULL, pages_to_gnt, segs_to_map); |
|
|
|
/* |
|
* Now swizzle the MFN in our domain with the MFN from the other domain |
|
* so that when we access vaddr(pending_req,i) it has the contents of |
|
* the page from the other domain. |
|
*/ |
|
for (seg_idx = last_map, new_map_idx = 0; seg_idx < map_until; seg_idx++) { |
|
if (!pages[seg_idx]->persistent_gnt) { |
|
/* This is a newly mapped grant */ |
|
BUG_ON(new_map_idx >= segs_to_map); |
|
if (unlikely(map[new_map_idx].status != 0)) { |
|
pr_debug("invalid buffer -- could not remap it\n"); |
|
gnttab_page_cache_put(&ring->free_pages, |
|
&pages[seg_idx]->page, 1); |
|
pages[seg_idx]->handle = BLKBACK_INVALID_HANDLE; |
|
ret |= !ret; |
|
goto next; |
|
} |
|
pages[seg_idx]->handle = map[new_map_idx].handle; |
|
} else { |
|
continue; |
|
} |
|
if (use_persistent_gnts && |
|
ring->persistent_gnt_c < max_pgrants) { |
|
/* |
|
* We are using persistent grants, the grant is |
|
* not mapped but we might have room for it. |
|
*/ |
|
persistent_gnt = kmalloc(sizeof(struct persistent_gnt), |
|
GFP_KERNEL); |
|
if (!persistent_gnt) { |
|
/* |
|
* If we don't have enough memory to |
|
* allocate the persistent_gnt struct |
|
* map this grant non-persistenly |
|
*/ |
|
goto next; |
|
} |
|
persistent_gnt->gnt = map[new_map_idx].ref; |
|
persistent_gnt->handle = map[new_map_idx].handle; |
|
persistent_gnt->page = pages[seg_idx]->page; |
|
if (add_persistent_gnt(ring, |
|
persistent_gnt)) { |
|
kfree(persistent_gnt); |
|
persistent_gnt = NULL; |
|
goto next; |
|
} |
|
pages[seg_idx]->persistent_gnt = persistent_gnt; |
|
pr_debug("grant %u added to the tree of persistent grants, using %u/%u\n", |
|
persistent_gnt->gnt, ring->persistent_gnt_c, |
|
max_pgrants); |
|
goto next; |
|
} |
|
if (use_persistent_gnts && !blkif->vbd.overflow_max_grants) { |
|
blkif->vbd.overflow_max_grants = 1; |
|
pr_debug("domain %u, device %#x is using maximum number of persistent grants\n", |
|
blkif->domid, blkif->vbd.handle); |
|
} |
|
/* |
|
* We could not map this grant persistently, so use it as |
|
* a non-persistent grant. |
|
*/ |
|
next: |
|
new_map_idx++; |
|
} |
|
segs_to_map = 0; |
|
last_map = map_until; |
|
if (!ret && map_until != num) |
|
goto again; |
|
|
|
out: |
|
for (i = last_map; i < num; i++) { |
|
/* Don't zap current batch's valid persistent grants. */ |
|
if(i >= map_until) |
|
pages[i]->persistent_gnt = NULL; |
|
pages[i]->handle = BLKBACK_INVALID_HANDLE; |
|
} |
|
|
|
return ret; |
|
} |
|
|
|
static int xen_blkbk_map_seg(struct pending_req *pending_req) |
|
{ |
|
int rc; |
|
|
|
rc = xen_blkbk_map(pending_req->ring, pending_req->segments, |
|
pending_req->nr_segs, |
|
(pending_req->operation != BLKIF_OP_READ)); |
|
|
|
return rc; |
|
} |
|
|
|
static int xen_blkbk_parse_indirect(struct blkif_request *req, |
|
struct pending_req *pending_req, |
|
struct seg_buf seg[], |
|
struct phys_req *preq) |
|
{ |
|
struct grant_page **pages = pending_req->indirect_pages; |
|
struct xen_blkif_ring *ring = pending_req->ring; |
|
int indirect_grefs, rc, n, nseg, i; |
|
struct blkif_request_segment *segments = NULL; |
|
|
|
nseg = pending_req->nr_segs; |
|
indirect_grefs = INDIRECT_PAGES(nseg); |
|
BUG_ON(indirect_grefs > BLKIF_MAX_INDIRECT_PAGES_PER_REQUEST); |
|
|
|
for (i = 0; i < indirect_grefs; i++) |
|
pages[i]->gref = req->u.indirect.indirect_grefs[i]; |
|
|
|
rc = xen_blkbk_map(ring, pages, indirect_grefs, true); |
|
if (rc) |
|
goto unmap; |
|
|
|
for (n = 0, i = 0; n < nseg; n++) { |
|
uint8_t first_sect, last_sect; |
|
|
|
if ((n % SEGS_PER_INDIRECT_FRAME) == 0) { |
|
/* Map indirect segments */ |
|
if (segments) |
|
kunmap_atomic(segments); |
|
segments = kmap_atomic(pages[n/SEGS_PER_INDIRECT_FRAME]->page); |
|
} |
|
i = n % SEGS_PER_INDIRECT_FRAME; |
|
|
|
pending_req->segments[n]->gref = segments[i].gref; |
|
|
|
first_sect = READ_ONCE(segments[i].first_sect); |
|
last_sect = READ_ONCE(segments[i].last_sect); |
|
if (last_sect >= (XEN_PAGE_SIZE >> 9) || last_sect < first_sect) { |
|
rc = -EINVAL; |
|
goto unmap; |
|
} |
|
|
|
seg[n].nsec = last_sect - first_sect + 1; |
|
seg[n].offset = first_sect << 9; |
|
preq->nr_sects += seg[n].nsec; |
|
} |
|
|
|
unmap: |
|
if (segments) |
|
kunmap_atomic(segments); |
|
xen_blkbk_unmap(ring, pages, indirect_grefs); |
|
return rc; |
|
} |
|
|
|
static int dispatch_discard_io(struct xen_blkif_ring *ring, |
|
struct blkif_request *req) |
|
{ |
|
int err = 0; |
|
int status = BLKIF_RSP_OKAY; |
|
struct xen_blkif *blkif = ring->blkif; |
|
struct block_device *bdev = blkif->vbd.bdev; |
|
unsigned long secure; |
|
struct phys_req preq; |
|
|
|
xen_blkif_get(blkif); |
|
|
|
preq.sector_number = req->u.discard.sector_number; |
|
preq.nr_sects = req->u.discard.nr_sectors; |
|
|
|
err = xen_vbd_translate(&preq, blkif, REQ_OP_WRITE); |
|
if (err) { |
|
pr_warn("access denied: DISCARD [%llu->%llu] on dev=%04x\n", |
|
preq.sector_number, |
|
preq.sector_number + preq.nr_sects, blkif->vbd.pdevice); |
|
goto fail_response; |
|
} |
|
ring->st_ds_req++; |
|
|
|
secure = (blkif->vbd.discard_secure && |
|
(req->u.discard.flag & BLKIF_DISCARD_SECURE)) ? |
|
BLKDEV_DISCARD_SECURE : 0; |
|
|
|
err = blkdev_issue_discard(bdev, req->u.discard.sector_number, |
|
req->u.discard.nr_sectors, |
|
GFP_KERNEL, secure); |
|
fail_response: |
|
if (err == -EOPNOTSUPP) { |
|
pr_debug("discard op failed, not supported\n"); |
|
status = BLKIF_RSP_EOPNOTSUPP; |
|
} else if (err) |
|
status = BLKIF_RSP_ERROR; |
|
|
|
make_response(ring, req->u.discard.id, req->operation, status); |
|
xen_blkif_put(blkif); |
|
return err; |
|
} |
|
|
|
static int dispatch_other_io(struct xen_blkif_ring *ring, |
|
struct blkif_request *req, |
|
struct pending_req *pending_req) |
|
{ |
|
free_req(ring, pending_req); |
|
make_response(ring, req->u.other.id, req->operation, |
|
BLKIF_RSP_EOPNOTSUPP); |
|
return -EIO; |
|
} |
|
|
|
static void xen_blk_drain_io(struct xen_blkif_ring *ring) |
|
{ |
|
struct xen_blkif *blkif = ring->blkif; |
|
|
|
atomic_set(&blkif->drain, 1); |
|
do { |
|
if (atomic_read(&ring->inflight) == 0) |
|
break; |
|
wait_for_completion_interruptible_timeout( |
|
&blkif->drain_complete, HZ); |
|
|
|
if (!atomic_read(&blkif->drain)) |
|
break; |
|
} while (!kthread_should_stop()); |
|
atomic_set(&blkif->drain, 0); |
|
} |
|
|
|
static void __end_block_io_op(struct pending_req *pending_req, |
|
blk_status_t error) |
|
{ |
|
/* An error fails the entire request. */ |
|
if (pending_req->operation == BLKIF_OP_FLUSH_DISKCACHE && |
|
error == BLK_STS_NOTSUPP) { |
|
pr_debug("flush diskcache op failed, not supported\n"); |
|
xen_blkbk_flush_diskcache(XBT_NIL, pending_req->ring->blkif->be, 0); |
|
pending_req->status = BLKIF_RSP_EOPNOTSUPP; |
|
} else if (pending_req->operation == BLKIF_OP_WRITE_BARRIER && |
|
error == BLK_STS_NOTSUPP) { |
|
pr_debug("write barrier op failed, not supported\n"); |
|
xen_blkbk_barrier(XBT_NIL, pending_req->ring->blkif->be, 0); |
|
pending_req->status = BLKIF_RSP_EOPNOTSUPP; |
|
} else if (error) { |
|
pr_debug("Buffer not up-to-date at end of operation," |
|
" error=%d\n", error); |
|
pending_req->status = BLKIF_RSP_ERROR; |
|
} |
|
|
|
/* |
|
* If all of the bio's have completed it is time to unmap |
|
* the grant references associated with 'request' and provide |
|
* the proper response on the ring. |
|
*/ |
|
if (atomic_dec_and_test(&pending_req->pendcnt)) |
|
xen_blkbk_unmap_and_respond(pending_req); |
|
} |
|
|
|
/* |
|
* bio callback. |
|
*/ |
|
static void end_block_io_op(struct bio *bio) |
|
{ |
|
__end_block_io_op(bio->bi_private, bio->bi_status); |
|
bio_put(bio); |
|
} |
|
|
|
|
|
|
|
/* |
|
* Function to copy the from the ring buffer the 'struct blkif_request' |
|
* (which has the sectors we want, number of them, grant references, etc), |
|
* and transmute it to the block API to hand it over to the proper block disk. |
|
*/ |
|
static int |
|
__do_block_io_op(struct xen_blkif_ring *ring, unsigned int *eoi_flags) |
|
{ |
|
union blkif_back_rings *blk_rings = &ring->blk_rings; |
|
struct blkif_request req; |
|
struct pending_req *pending_req; |
|
RING_IDX rc, rp; |
|
int more_to_do = 0; |
|
|
|
rc = blk_rings->common.req_cons; |
|
rp = blk_rings->common.sring->req_prod; |
|
rmb(); /* Ensure we see queued requests up to 'rp'. */ |
|
|
|
if (RING_REQUEST_PROD_OVERFLOW(&blk_rings->common, rp)) { |
|
rc = blk_rings->common.rsp_prod_pvt; |
|
pr_warn("Frontend provided bogus ring requests (%d - %d = %d). Halting ring processing on dev=%04x\n", |
|
rp, rc, rp - rc, ring->blkif->vbd.pdevice); |
|
return -EACCES; |
|
} |
|
while (rc != rp) { |
|
|
|
if (RING_REQUEST_CONS_OVERFLOW(&blk_rings->common, rc)) |
|
break; |
|
|
|
/* We've seen a request, so clear spurious eoi flag. */ |
|
*eoi_flags &= ~XEN_EOI_FLAG_SPURIOUS; |
|
|
|
if (kthread_should_stop()) { |
|
more_to_do = 1; |
|
break; |
|
} |
|
|
|
pending_req = alloc_req(ring); |
|
if (NULL == pending_req) { |
|
ring->st_oo_req++; |
|
more_to_do = 1; |
|
break; |
|
} |
|
|
|
switch (ring->blkif->blk_protocol) { |
|
case BLKIF_PROTOCOL_NATIVE: |
|
memcpy(&req, RING_GET_REQUEST(&blk_rings->native, rc), sizeof(req)); |
|
break; |
|
case BLKIF_PROTOCOL_X86_32: |
|
blkif_get_x86_32_req(&req, RING_GET_REQUEST(&blk_rings->x86_32, rc)); |
|
break; |
|
case BLKIF_PROTOCOL_X86_64: |
|
blkif_get_x86_64_req(&req, RING_GET_REQUEST(&blk_rings->x86_64, rc)); |
|
break; |
|
default: |
|
BUG(); |
|
} |
|
blk_rings->common.req_cons = ++rc; /* before make_response() */ |
|
|
|
/* Apply all sanity checks to /private copy/ of request. */ |
|
barrier(); |
|
|
|
switch (req.operation) { |
|
case BLKIF_OP_READ: |
|
case BLKIF_OP_WRITE: |
|
case BLKIF_OP_WRITE_BARRIER: |
|
case BLKIF_OP_FLUSH_DISKCACHE: |
|
case BLKIF_OP_INDIRECT: |
|
if (dispatch_rw_block_io(ring, &req, pending_req)) |
|
goto done; |
|
break; |
|
case BLKIF_OP_DISCARD: |
|
free_req(ring, pending_req); |
|
if (dispatch_discard_io(ring, &req)) |
|
goto done; |
|
break; |
|
default: |
|
if (dispatch_other_io(ring, &req, pending_req)) |
|
goto done; |
|
break; |
|
} |
|
|
|
/* Yield point for this unbounded loop. */ |
|
cond_resched(); |
|
} |
|
done: |
|
return more_to_do; |
|
} |
|
|
|
static int |
|
do_block_io_op(struct xen_blkif_ring *ring, unsigned int *eoi_flags) |
|
{ |
|
union blkif_back_rings *blk_rings = &ring->blk_rings; |
|
int more_to_do; |
|
|
|
do { |
|
more_to_do = __do_block_io_op(ring, eoi_flags); |
|
if (more_to_do) |
|
break; |
|
|
|
RING_FINAL_CHECK_FOR_REQUESTS(&blk_rings->common, more_to_do); |
|
} while (more_to_do); |
|
|
|
return more_to_do; |
|
} |
|
/* |
|
* Transmutation of the 'struct blkif_request' to a proper 'struct bio' |
|
* and call the 'submit_bio' to pass it to the underlying storage. |
|
*/ |
|
static int dispatch_rw_block_io(struct xen_blkif_ring *ring, |
|
struct blkif_request *req, |
|
struct pending_req *pending_req) |
|
{ |
|
struct phys_req preq; |
|
struct seg_buf *seg = pending_req->seg; |
|
unsigned int nseg; |
|
struct bio *bio = NULL; |
|
struct bio **biolist = pending_req->biolist; |
|
int i, nbio = 0; |
|
int operation; |
|
int operation_flags = 0; |
|
struct blk_plug plug; |
|
bool drain = false; |
|
struct grant_page **pages = pending_req->segments; |
|
unsigned short req_operation; |
|
|
|
req_operation = req->operation == BLKIF_OP_INDIRECT ? |
|
req->u.indirect.indirect_op : req->operation; |
|
|
|
if ((req->operation == BLKIF_OP_INDIRECT) && |
|
(req_operation != BLKIF_OP_READ) && |
|
(req_operation != BLKIF_OP_WRITE)) { |
|
pr_debug("Invalid indirect operation (%u)\n", req_operation); |
|
goto fail_response; |
|
} |
|
|
|
switch (req_operation) { |
|
case BLKIF_OP_READ: |
|
ring->st_rd_req++; |
|
operation = REQ_OP_READ; |
|
break; |
|
case BLKIF_OP_WRITE: |
|
ring->st_wr_req++; |
|
operation = REQ_OP_WRITE; |
|
operation_flags = REQ_SYNC | REQ_IDLE; |
|
break; |
|
case BLKIF_OP_WRITE_BARRIER: |
|
drain = true; |
|
fallthrough; |
|
case BLKIF_OP_FLUSH_DISKCACHE: |
|
ring->st_f_req++; |
|
operation = REQ_OP_WRITE; |
|
operation_flags = REQ_PREFLUSH; |
|
break; |
|
default: |
|
operation = 0; /* make gcc happy */ |
|
goto fail_response; |
|
break; |
|
} |
|
|
|
/* Check that the number of segments is sane. */ |
|
nseg = req->operation == BLKIF_OP_INDIRECT ? |
|
req->u.indirect.nr_segments : req->u.rw.nr_segments; |
|
|
|
if (unlikely(nseg == 0 && operation_flags != REQ_PREFLUSH) || |
|
unlikely((req->operation != BLKIF_OP_INDIRECT) && |
|
(nseg > BLKIF_MAX_SEGMENTS_PER_REQUEST)) || |
|
unlikely((req->operation == BLKIF_OP_INDIRECT) && |
|
(nseg > MAX_INDIRECT_SEGMENTS))) { |
|
pr_debug("Bad number of segments in request (%d)\n", nseg); |
|
/* Haven't submitted any bio's yet. */ |
|
goto fail_response; |
|
} |
|
|
|
preq.nr_sects = 0; |
|
|
|
pending_req->ring = ring; |
|
pending_req->id = req->u.rw.id; |
|
pending_req->operation = req_operation; |
|
pending_req->status = BLKIF_RSP_OKAY; |
|
pending_req->nr_segs = nseg; |
|
|
|
if (req->operation != BLKIF_OP_INDIRECT) { |
|
preq.dev = req->u.rw.handle; |
|
preq.sector_number = req->u.rw.sector_number; |
|
for (i = 0; i < nseg; i++) { |
|
pages[i]->gref = req->u.rw.seg[i].gref; |
|
seg[i].nsec = req->u.rw.seg[i].last_sect - |
|
req->u.rw.seg[i].first_sect + 1; |
|
seg[i].offset = (req->u.rw.seg[i].first_sect << 9); |
|
if ((req->u.rw.seg[i].last_sect >= (XEN_PAGE_SIZE >> 9)) || |
|
(req->u.rw.seg[i].last_sect < |
|
req->u.rw.seg[i].first_sect)) |
|
goto fail_response; |
|
preq.nr_sects += seg[i].nsec; |
|
} |
|
} else { |
|
preq.dev = req->u.indirect.handle; |
|
preq.sector_number = req->u.indirect.sector_number; |
|
if (xen_blkbk_parse_indirect(req, pending_req, seg, &preq)) |
|
goto fail_response; |
|
} |
|
|
|
if (xen_vbd_translate(&preq, ring->blkif, operation) != 0) { |
|
pr_debug("access denied: %s of [%llu,%llu] on dev=%04x\n", |
|
operation == REQ_OP_READ ? "read" : "write", |
|
preq.sector_number, |
|
preq.sector_number + preq.nr_sects, |
|
ring->blkif->vbd.pdevice); |
|
goto fail_response; |
|
} |
|
|
|
/* |
|
* This check _MUST_ be done after xen_vbd_translate as the preq.bdev |
|
* is set there. |
|
*/ |
|
for (i = 0; i < nseg; i++) { |
|
if (((int)preq.sector_number|(int)seg[i].nsec) & |
|
((bdev_logical_block_size(preq.bdev) >> 9) - 1)) { |
|
pr_debug("Misaligned I/O request from domain %d\n", |
|
ring->blkif->domid); |
|
goto fail_response; |
|
} |
|
} |
|
|
|
/* Wait on all outstanding I/O's and once that has been completed |
|
* issue the flush. |
|
*/ |
|
if (drain) |
|
xen_blk_drain_io(pending_req->ring); |
|
|
|
/* |
|
* If we have failed at this point, we need to undo the M2P override, |
|
* set gnttab_set_unmap_op on all of the grant references and perform |
|
* the hypercall to unmap the grants - that is all done in |
|
* xen_blkbk_unmap. |
|
*/ |
|
if (xen_blkbk_map_seg(pending_req)) |
|
goto fail_flush; |
|
|
|
/* |
|
* This corresponding xen_blkif_put is done in __end_block_io_op, or |
|
* below (in "!bio") if we are handling a BLKIF_OP_DISCARD. |
|
*/ |
|
xen_blkif_get(ring->blkif); |
|
atomic_inc(&ring->inflight); |
|
|
|
for (i = 0; i < nseg; i++) { |
|
while ((bio == NULL) || |
|
(bio_add_page(bio, |
|
pages[i]->page, |
|
seg[i].nsec << 9, |
|
seg[i].offset) == 0)) { |
|
bio = bio_alloc(GFP_KERNEL, bio_max_segs(nseg - i)); |
|
if (unlikely(bio == NULL)) |
|
goto fail_put_bio; |
|
|
|
biolist[nbio++] = bio; |
|
bio_set_dev(bio, preq.bdev); |
|
bio->bi_private = pending_req; |
|
bio->bi_end_io = end_block_io_op; |
|
bio->bi_iter.bi_sector = preq.sector_number; |
|
bio_set_op_attrs(bio, operation, operation_flags); |
|
} |
|
|
|
preq.sector_number += seg[i].nsec; |
|
} |
|
|
|
/* This will be hit if the operation was a flush or discard. */ |
|
if (!bio) { |
|
BUG_ON(operation_flags != REQ_PREFLUSH); |
|
|
|
bio = bio_alloc(GFP_KERNEL, 0); |
|
if (unlikely(bio == NULL)) |
|
goto fail_put_bio; |
|
|
|
biolist[nbio++] = bio; |
|
bio_set_dev(bio, preq.bdev); |
|
bio->bi_private = pending_req; |
|
bio->bi_end_io = end_block_io_op; |
|
bio_set_op_attrs(bio, operation, operation_flags); |
|
} |
|
|
|
atomic_set(&pending_req->pendcnt, nbio); |
|
blk_start_plug(&plug); |
|
|
|
for (i = 0; i < nbio; i++) |
|
submit_bio(biolist[i]); |
|
|
|
/* Let the I/Os go.. */ |
|
blk_finish_plug(&plug); |
|
|
|
if (operation == REQ_OP_READ) |
|
ring->st_rd_sect += preq.nr_sects; |
|
else if (operation == REQ_OP_WRITE) |
|
ring->st_wr_sect += preq.nr_sects; |
|
|
|
return 0; |
|
|
|
fail_flush: |
|
xen_blkbk_unmap(ring, pending_req->segments, |
|
pending_req->nr_segs); |
|
fail_response: |
|
/* Haven't submitted any bio's yet. */ |
|
make_response(ring, req->u.rw.id, req_operation, BLKIF_RSP_ERROR); |
|
free_req(ring, pending_req); |
|
msleep(1); /* back off a bit */ |
|
return -EIO; |
|
|
|
fail_put_bio: |
|
for (i = 0; i < nbio; i++) |
|
bio_put(biolist[i]); |
|
atomic_set(&pending_req->pendcnt, 1); |
|
__end_block_io_op(pending_req, BLK_STS_RESOURCE); |
|
msleep(1); /* back off a bit */ |
|
return -EIO; |
|
} |
|
|
|
|
|
|
|
/* |
|
* Put a response on the ring on how the operation fared. |
|
*/ |
|
static void make_response(struct xen_blkif_ring *ring, u64 id, |
|
unsigned short op, int st) |
|
{ |
|
struct blkif_response *resp; |
|
unsigned long flags; |
|
union blkif_back_rings *blk_rings; |
|
int notify; |
|
|
|
spin_lock_irqsave(&ring->blk_ring_lock, flags); |
|
blk_rings = &ring->blk_rings; |
|
/* Place on the response ring for the relevant domain. */ |
|
switch (ring->blkif->blk_protocol) { |
|
case BLKIF_PROTOCOL_NATIVE: |
|
resp = RING_GET_RESPONSE(&blk_rings->native, |
|
blk_rings->native.rsp_prod_pvt); |
|
break; |
|
case BLKIF_PROTOCOL_X86_32: |
|
resp = RING_GET_RESPONSE(&blk_rings->x86_32, |
|
blk_rings->x86_32.rsp_prod_pvt); |
|
break; |
|
case BLKIF_PROTOCOL_X86_64: |
|
resp = RING_GET_RESPONSE(&blk_rings->x86_64, |
|
blk_rings->x86_64.rsp_prod_pvt); |
|
break; |
|
default: |
|
BUG(); |
|
} |
|
|
|
resp->id = id; |
|
resp->operation = op; |
|
resp->status = st; |
|
|
|
blk_rings->common.rsp_prod_pvt++; |
|
RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&blk_rings->common, notify); |
|
spin_unlock_irqrestore(&ring->blk_ring_lock, flags); |
|
if (notify) |
|
notify_remote_via_irq(ring->irq); |
|
} |
|
|
|
static int __init xen_blkif_init(void) |
|
{ |
|
int rc = 0; |
|
|
|
if (!xen_domain()) |
|
return -ENODEV; |
|
|
|
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 (xenblk_max_queues == 0) |
|
xenblk_max_queues = num_online_cpus(); |
|
|
|
rc = xen_blkif_interface_init(); |
|
if (rc) |
|
goto failed_init; |
|
|
|
rc = xen_blkif_xenbus_init(); |
|
if (rc) |
|
goto failed_init; |
|
|
|
failed_init: |
|
return rc; |
|
} |
|
|
|
module_init(xen_blkif_init); |
|
|
|
static void __exit xen_blkif_fini(void) |
|
{ |
|
xen_blkif_xenbus_fini(); |
|
xen_blkif_interface_fini(); |
|
} |
|
|
|
module_exit(xen_blkif_fini); |
|
|
|
MODULE_LICENSE("Dual BSD/GPL"); |
|
MODULE_ALIAS("xen-backend:vbd");
|
|
|