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522 lines
11 KiB
522 lines
11 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* bsg.c - block layer implementation of the sg v4 interface |
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*/ |
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#include <linux/module.h> |
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#include <linux/init.h> |
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#include <linux/file.h> |
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#include <linux/blkdev.h> |
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#include <linux/cdev.h> |
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#include <linux/jiffies.h> |
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#include <linux/percpu.h> |
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#include <linux/idr.h> |
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#include <linux/bsg.h> |
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#include <linux/slab.h> |
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#include <scsi/scsi.h> |
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#include <scsi/scsi_ioctl.h> |
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#include <scsi/scsi_cmnd.h> |
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#include <scsi/scsi_device.h> |
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#include <scsi/scsi_driver.h> |
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#include <scsi/sg.h> |
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#define BSG_DESCRIPTION "Block layer SCSI generic (bsg) driver" |
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#define BSG_VERSION "0.4" |
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#define bsg_dbg(bd, fmt, ...) \ |
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pr_debug("%s: " fmt, (bd)->name, ##__VA_ARGS__) |
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struct bsg_device { |
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struct request_queue *queue; |
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spinlock_t lock; |
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struct hlist_node dev_list; |
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refcount_t ref_count; |
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char name[20]; |
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int max_queue; |
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}; |
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#define BSG_DEFAULT_CMDS 64 |
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#define BSG_MAX_DEVS 32768 |
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static DEFINE_MUTEX(bsg_mutex); |
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static DEFINE_IDR(bsg_minor_idr); |
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#define BSG_LIST_ARRAY_SIZE 8 |
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static struct hlist_head bsg_device_list[BSG_LIST_ARRAY_SIZE]; |
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static struct class *bsg_class; |
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static int bsg_major; |
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static inline struct hlist_head *bsg_dev_idx_hash(int index) |
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{ |
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return &bsg_device_list[index & (BSG_LIST_ARRAY_SIZE - 1)]; |
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} |
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#define uptr64(val) ((void __user *)(uintptr_t)(val)) |
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static int bsg_scsi_check_proto(struct sg_io_v4 *hdr) |
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{ |
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if (hdr->protocol != BSG_PROTOCOL_SCSI || |
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hdr->subprotocol != BSG_SUB_PROTOCOL_SCSI_CMD) |
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return -EINVAL; |
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return 0; |
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} |
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static int bsg_scsi_fill_hdr(struct request *rq, struct sg_io_v4 *hdr, |
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fmode_t mode) |
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{ |
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struct scsi_request *sreq = scsi_req(rq); |
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if (hdr->dout_xfer_len && hdr->din_xfer_len) { |
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pr_warn_once("BIDI support in bsg has been removed.\n"); |
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return -EOPNOTSUPP; |
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} |
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sreq->cmd_len = hdr->request_len; |
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if (sreq->cmd_len > BLK_MAX_CDB) { |
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sreq->cmd = kzalloc(sreq->cmd_len, GFP_KERNEL); |
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if (!sreq->cmd) |
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return -ENOMEM; |
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} |
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if (copy_from_user(sreq->cmd, uptr64(hdr->request), sreq->cmd_len)) |
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return -EFAULT; |
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if (blk_verify_command(sreq->cmd, mode)) |
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return -EPERM; |
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return 0; |
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} |
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static int bsg_scsi_complete_rq(struct request *rq, struct sg_io_v4 *hdr) |
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{ |
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struct scsi_request *sreq = scsi_req(rq); |
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int ret = 0; |
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/* |
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* fill in all the output members |
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*/ |
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hdr->device_status = sreq->result & 0xff; |
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hdr->transport_status = host_byte(sreq->result); |
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hdr->driver_status = driver_byte(sreq->result); |
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hdr->info = 0; |
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if (hdr->device_status || hdr->transport_status || hdr->driver_status) |
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hdr->info |= SG_INFO_CHECK; |
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hdr->response_len = 0; |
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if (sreq->sense_len && hdr->response) { |
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int len = min_t(unsigned int, hdr->max_response_len, |
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sreq->sense_len); |
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if (copy_to_user(uptr64(hdr->response), sreq->sense, len)) |
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ret = -EFAULT; |
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else |
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hdr->response_len = len; |
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} |
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if (rq_data_dir(rq) == READ) |
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hdr->din_resid = sreq->resid_len; |
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else |
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hdr->dout_resid = sreq->resid_len; |
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return ret; |
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} |
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static void bsg_scsi_free_rq(struct request *rq) |
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{ |
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scsi_req_free_cmd(scsi_req(rq)); |
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} |
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static const struct bsg_ops bsg_scsi_ops = { |
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.check_proto = bsg_scsi_check_proto, |
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.fill_hdr = bsg_scsi_fill_hdr, |
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.complete_rq = bsg_scsi_complete_rq, |
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.free_rq = bsg_scsi_free_rq, |
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}; |
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static int bsg_sg_io(struct request_queue *q, fmode_t mode, void __user *uarg) |
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{ |
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struct request *rq; |
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struct bio *bio; |
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struct sg_io_v4 hdr; |
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int ret; |
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if (copy_from_user(&hdr, uarg, sizeof(hdr))) |
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return -EFAULT; |
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if (!q->bsg_dev.class_dev) |
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return -ENXIO; |
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if (hdr.guard != 'Q') |
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return -EINVAL; |
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ret = q->bsg_dev.ops->check_proto(&hdr); |
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if (ret) |
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return ret; |
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rq = blk_get_request(q, hdr.dout_xfer_len ? |
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REQ_OP_SCSI_OUT : REQ_OP_SCSI_IN, 0); |
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if (IS_ERR(rq)) |
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return PTR_ERR(rq); |
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ret = q->bsg_dev.ops->fill_hdr(rq, &hdr, mode); |
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if (ret) { |
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blk_put_request(rq); |
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return ret; |
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} |
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rq->timeout = msecs_to_jiffies(hdr.timeout); |
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if (!rq->timeout) |
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rq->timeout = q->sg_timeout; |
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if (!rq->timeout) |
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rq->timeout = BLK_DEFAULT_SG_TIMEOUT; |
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if (rq->timeout < BLK_MIN_SG_TIMEOUT) |
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rq->timeout = BLK_MIN_SG_TIMEOUT; |
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if (hdr.dout_xfer_len) { |
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ret = blk_rq_map_user(q, rq, NULL, uptr64(hdr.dout_xferp), |
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hdr.dout_xfer_len, GFP_KERNEL); |
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} else if (hdr.din_xfer_len) { |
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ret = blk_rq_map_user(q, rq, NULL, uptr64(hdr.din_xferp), |
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hdr.din_xfer_len, GFP_KERNEL); |
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} |
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if (ret) |
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goto out_free_rq; |
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bio = rq->bio; |
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blk_execute_rq(NULL, rq, !(hdr.flags & BSG_FLAG_Q_AT_TAIL)); |
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ret = rq->q->bsg_dev.ops->complete_rq(rq, &hdr); |
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blk_rq_unmap_user(bio); |
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out_free_rq: |
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rq->q->bsg_dev.ops->free_rq(rq); |
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blk_put_request(rq); |
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if (!ret && copy_to_user(uarg, &hdr, sizeof(hdr))) |
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return -EFAULT; |
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return ret; |
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} |
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static struct bsg_device *bsg_alloc_device(void) |
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{ |
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struct bsg_device *bd; |
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bd = kzalloc(sizeof(struct bsg_device), GFP_KERNEL); |
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if (unlikely(!bd)) |
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return NULL; |
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spin_lock_init(&bd->lock); |
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bd->max_queue = BSG_DEFAULT_CMDS; |
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INIT_HLIST_NODE(&bd->dev_list); |
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return bd; |
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} |
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static int bsg_put_device(struct bsg_device *bd) |
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{ |
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struct request_queue *q = bd->queue; |
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mutex_lock(&bsg_mutex); |
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if (!refcount_dec_and_test(&bd->ref_count)) { |
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mutex_unlock(&bsg_mutex); |
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return 0; |
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} |
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hlist_del(&bd->dev_list); |
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mutex_unlock(&bsg_mutex); |
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bsg_dbg(bd, "tearing down\n"); |
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/* |
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* close can always block |
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*/ |
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kfree(bd); |
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blk_put_queue(q); |
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return 0; |
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} |
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static struct bsg_device *bsg_add_device(struct inode *inode, |
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struct request_queue *rq, |
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struct file *file) |
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{ |
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struct bsg_device *bd; |
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unsigned char buf[32]; |
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lockdep_assert_held(&bsg_mutex); |
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if (!blk_get_queue(rq)) |
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return ERR_PTR(-ENXIO); |
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bd = bsg_alloc_device(); |
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if (!bd) { |
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blk_put_queue(rq); |
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return ERR_PTR(-ENOMEM); |
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} |
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bd->queue = rq; |
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refcount_set(&bd->ref_count, 1); |
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hlist_add_head(&bd->dev_list, bsg_dev_idx_hash(iminor(inode))); |
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strncpy(bd->name, dev_name(rq->bsg_dev.class_dev), sizeof(bd->name) - 1); |
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bsg_dbg(bd, "bound to <%s>, max queue %d\n", |
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format_dev_t(buf, inode->i_rdev), bd->max_queue); |
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return bd; |
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} |
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static struct bsg_device *__bsg_get_device(int minor, struct request_queue *q) |
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{ |
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struct bsg_device *bd; |
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lockdep_assert_held(&bsg_mutex); |
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hlist_for_each_entry(bd, bsg_dev_idx_hash(minor), dev_list) { |
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if (bd->queue == q) { |
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refcount_inc(&bd->ref_count); |
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goto found; |
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} |
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} |
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bd = NULL; |
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found: |
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return bd; |
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} |
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static struct bsg_device *bsg_get_device(struct inode *inode, struct file *file) |
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{ |
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struct bsg_device *bd; |
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struct bsg_class_device *bcd; |
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/* |
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* find the class device |
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*/ |
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mutex_lock(&bsg_mutex); |
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bcd = idr_find(&bsg_minor_idr, iminor(inode)); |
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if (!bcd) { |
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bd = ERR_PTR(-ENODEV); |
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goto out_unlock; |
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} |
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bd = __bsg_get_device(iminor(inode), bcd->queue); |
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if (!bd) |
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bd = bsg_add_device(inode, bcd->queue, file); |
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out_unlock: |
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mutex_unlock(&bsg_mutex); |
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return bd; |
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} |
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static int bsg_open(struct inode *inode, struct file *file) |
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{ |
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struct bsg_device *bd; |
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bd = bsg_get_device(inode, file); |
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if (IS_ERR(bd)) |
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return PTR_ERR(bd); |
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file->private_data = bd; |
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return 0; |
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} |
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static int bsg_release(struct inode *inode, struct file *file) |
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{ |
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struct bsg_device *bd = file->private_data; |
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file->private_data = NULL; |
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return bsg_put_device(bd); |
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} |
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static int bsg_get_command_q(struct bsg_device *bd, int __user *uarg) |
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{ |
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return put_user(bd->max_queue, uarg); |
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} |
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static int bsg_set_command_q(struct bsg_device *bd, int __user *uarg) |
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{ |
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int queue; |
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if (get_user(queue, uarg)) |
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return -EFAULT; |
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if (queue < 1) |
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return -EINVAL; |
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spin_lock_irq(&bd->lock); |
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bd->max_queue = queue; |
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spin_unlock_irq(&bd->lock); |
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return 0; |
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} |
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static long bsg_ioctl(struct file *file, unsigned int cmd, unsigned long arg) |
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{ |
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struct bsg_device *bd = file->private_data; |
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void __user *uarg = (void __user *) arg; |
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switch (cmd) { |
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/* |
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* Our own ioctls |
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*/ |
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case SG_GET_COMMAND_Q: |
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return bsg_get_command_q(bd, uarg); |
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case SG_SET_COMMAND_Q: |
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return bsg_set_command_q(bd, uarg); |
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/* |
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* SCSI/sg ioctls |
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*/ |
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case SG_GET_VERSION_NUM: |
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case SCSI_IOCTL_GET_IDLUN: |
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case SCSI_IOCTL_GET_BUS_NUMBER: |
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case SG_SET_TIMEOUT: |
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case SG_GET_TIMEOUT: |
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case SG_GET_RESERVED_SIZE: |
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case SG_SET_RESERVED_SIZE: |
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case SG_EMULATED_HOST: |
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case SCSI_IOCTL_SEND_COMMAND: |
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return scsi_cmd_ioctl(bd->queue, NULL, file->f_mode, cmd, uarg); |
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case SG_IO: |
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return bsg_sg_io(bd->queue, file->f_mode, uarg); |
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default: |
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return -ENOTTY; |
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} |
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} |
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static const struct file_operations bsg_fops = { |
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.open = bsg_open, |
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.release = bsg_release, |
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.unlocked_ioctl = bsg_ioctl, |
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.compat_ioctl = compat_ptr_ioctl, |
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.owner = THIS_MODULE, |
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.llseek = default_llseek, |
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}; |
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void bsg_unregister_queue(struct request_queue *q) |
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{ |
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struct bsg_class_device *bcd = &q->bsg_dev; |
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if (!bcd->class_dev) |
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return; |
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mutex_lock(&bsg_mutex); |
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idr_remove(&bsg_minor_idr, bcd->minor); |
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if (q->kobj.sd) |
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sysfs_remove_link(&q->kobj, "bsg"); |
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device_unregister(bcd->class_dev); |
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bcd->class_dev = NULL; |
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mutex_unlock(&bsg_mutex); |
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} |
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EXPORT_SYMBOL_GPL(bsg_unregister_queue); |
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int bsg_register_queue(struct request_queue *q, struct device *parent, |
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const char *name, const struct bsg_ops *ops) |
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{ |
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struct bsg_class_device *bcd; |
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dev_t dev; |
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int ret; |
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struct device *class_dev = NULL; |
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/* |
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* we need a proper transport to send commands, not a stacked device |
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*/ |
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if (!queue_is_mq(q)) |
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return 0; |
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bcd = &q->bsg_dev; |
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memset(bcd, 0, sizeof(*bcd)); |
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mutex_lock(&bsg_mutex); |
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ret = idr_alloc(&bsg_minor_idr, bcd, 0, BSG_MAX_DEVS, GFP_KERNEL); |
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if (ret < 0) { |
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if (ret == -ENOSPC) { |
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printk(KERN_ERR "bsg: too many bsg devices\n"); |
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ret = -EINVAL; |
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} |
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goto unlock; |
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} |
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bcd->minor = ret; |
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bcd->queue = q; |
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bcd->ops = ops; |
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dev = MKDEV(bsg_major, bcd->minor); |
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class_dev = device_create(bsg_class, parent, dev, NULL, "%s", name); |
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if (IS_ERR(class_dev)) { |
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ret = PTR_ERR(class_dev); |
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goto idr_remove; |
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} |
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bcd->class_dev = class_dev; |
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if (q->kobj.sd) { |
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ret = sysfs_create_link(&q->kobj, &bcd->class_dev->kobj, "bsg"); |
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if (ret) |
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goto unregister_class_dev; |
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} |
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mutex_unlock(&bsg_mutex); |
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return 0; |
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unregister_class_dev: |
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device_unregister(class_dev); |
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idr_remove: |
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idr_remove(&bsg_minor_idr, bcd->minor); |
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unlock: |
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mutex_unlock(&bsg_mutex); |
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return ret; |
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} |
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int bsg_scsi_register_queue(struct request_queue *q, struct device *parent) |
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{ |
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if (!blk_queue_scsi_passthrough(q)) { |
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WARN_ONCE(true, "Attempt to register a non-SCSI queue\n"); |
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return -EINVAL; |
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} |
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return bsg_register_queue(q, parent, dev_name(parent), &bsg_scsi_ops); |
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} |
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EXPORT_SYMBOL_GPL(bsg_scsi_register_queue); |
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static struct cdev bsg_cdev; |
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static char *bsg_devnode(struct device *dev, umode_t *mode) |
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{ |
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return kasprintf(GFP_KERNEL, "bsg/%s", dev_name(dev)); |
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} |
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static int __init bsg_init(void) |
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{ |
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int ret, i; |
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dev_t devid; |
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for (i = 0; i < BSG_LIST_ARRAY_SIZE; i++) |
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INIT_HLIST_HEAD(&bsg_device_list[i]); |
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bsg_class = class_create(THIS_MODULE, "bsg"); |
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if (IS_ERR(bsg_class)) |
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return PTR_ERR(bsg_class); |
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bsg_class->devnode = bsg_devnode; |
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ret = alloc_chrdev_region(&devid, 0, BSG_MAX_DEVS, "bsg"); |
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if (ret) |
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goto destroy_bsg_class; |
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bsg_major = MAJOR(devid); |
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cdev_init(&bsg_cdev, &bsg_fops); |
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ret = cdev_add(&bsg_cdev, MKDEV(bsg_major, 0), BSG_MAX_DEVS); |
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if (ret) |
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goto unregister_chrdev; |
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printk(KERN_INFO BSG_DESCRIPTION " version " BSG_VERSION |
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" loaded (major %d)\n", bsg_major); |
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return 0; |
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unregister_chrdev: |
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unregister_chrdev_region(MKDEV(bsg_major, 0), BSG_MAX_DEVS); |
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destroy_bsg_class: |
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class_destroy(bsg_class); |
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return ret; |
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} |
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MODULE_AUTHOR("Jens Axboe"); |
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MODULE_DESCRIPTION(BSG_DESCRIPTION); |
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MODULE_LICENSE("GPL"); |
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device_initcall(bsg_init);
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