bsg-lib: fix kernel panic resulting from missing allocation of reply-buffer
Since we split the scsi_request out of struct request bsg fails to
provide a reply-buffer for the drivers. This was done via the pointer
for sense-data, that is not preallocated anymore.
Failing to allocate/assign it results in illegal dereferences because
LLDs use this pointer unquestioned.
An example panic on s390x, using the zFCP driver, looks like this (I had
debugging on, otherwise NULL-pointer dereferences wouldn't even panic on
s390x):
Unable to handle kernel pointer dereference in virtual kernel address space
Failing address: 6b6b6b6b6b6b6000 TEID: 6b6b6b6b6b6b6403
Fault in home space mode while using kernel ASCE.
AS:0000000001590007 R3:0000000000000024
Oops: 0038 ilc:2 [#1] PREEMPT SMP DEBUG_PAGEALLOC
Modules linked in: <Long List>
CPU: 2 PID: 0 Comm: swapper/2 Not tainted 4.12.0-bsg-regression+ #3
Hardware name: IBM 2964 N96 702 (z/VM 6.4.0)
task: 0000000065cb0100 task.stack: 0000000065cb4000
Krnl PSW : 0704e00180000000 000003ff801e4156 (zfcp_fc_ct_els_job_handler+0x16/0x58 [zfcp])
R:0 T:1 IO:1 EX:1 Key:0 M:1 W:0 P:0 AS:3 CC:2 PM:0 RI:0 EA:3
Krnl GPRS: 0000000000000001 000000005fa9d0d0 000000005fa9d078 0000000000e16866
000003ff00000290 6b6b6b6b6b6b6b6b 0000000059f78f00 000000000000000f
00000000593a0958 00000000593a0958 0000000060d88800 000000005ddd4c38
0000000058b50100 07000000659cba08 000003ff801e8556 00000000659cb9a8
Krnl Code: 000003ff801e4146: e31020500004 lg %r1,80(%r2)
000003ff801e414c: 58402040 l %r4,64(%r2)
#000003ff801e4150: e35020200004 lg %r5,32(%r2)
>000003ff801e4156: 50405004 st %r4,4(%r5)
000003ff801e415a: e54c50080000 mvhi 8(%r5),0
000003ff801e4160: e33010280012 lt %r3,40(%r1)
000003ff801e4166: a718fffb lhi %r1,-5
000003ff801e416a: 1803 lr %r0,%r3
Call Trace:
([<000003ff801e8556>] zfcp_fsf_req_complete+0x726/0x768 [zfcp])
[<000003ff801ea82a>] zfcp_fsf_reqid_check+0x102/0x180 [zfcp]
[<000003ff801eb980>] zfcp_qdio_int_resp+0x230/0x278 [zfcp]
[<00000000009b91b6>] qdio_kick_handler+0x2ae/0x2c8
[<00000000009b9e3e>] __tiqdio_inbound_processing+0x406/0xc10
[<00000000001684c2>] tasklet_action+0x15a/0x1d8
[<0000000000bd28ec>] __do_softirq+0x3ec/0x848
[<00000000001675a4>] irq_exit+0x74/0xf8
[<000000000010dd6a>] do_IRQ+0xba/0xf0
[<0000000000bd19e8>] io_int_handler+0x104/0x2d4
[<00000000001033b6>] enabled_wait+0xb6/0x188
([<000000000010339e>] enabled_wait+0x9e/0x188)
[<000000000010396a>] arch_cpu_idle+0x32/0x50
[<0000000000bd0112>] default_idle_call+0x52/0x68
[<00000000001cd0fa>] do_idle+0x102/0x188
[<00000000001cd41e>] cpu_startup_entry+0x3e/0x48
[<0000000000118c64>] smp_start_secondary+0x11c/0x130
[<0000000000bd2016>] restart_int_handler+0x62/0x78
[<0000000000000000>] (null)
INFO: lockdep is turned off.
Last Breaking-Event-Address:
[<000003ff801e41d6>] zfcp_fc_ct_job_handler+0x3e/0x48 [zfcp]
Kernel panic - not syncing: Fatal exception in interrupt
This patch moves bsg-lib to allocate and setup struct bsg_job ahead of
time, including the allocation of a buffer for the reply-data.
This means, struct bsg_job is not allocated separately anymore, but as part
of struct request allocation - similar to struct scsi_cmd. Reflect this in
the function names that used to handle creation/destruction of struct
bsg_job.
Reported-by: Steffen Maier <maier@linux.vnet.ibm.com>
Suggested-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Benjamin Block <bblock@linux.vnet.ibm.com>
Fixes: 82ed4db499 ("block: split scsi_request out of struct request")
Cc: <stable@vger.kernel.org> #4.11+
Signed-off-by: Jens Axboe <axboe@kernel.dk>
hifive-unleashed-5.1
Benjamin Block
Jens Axboe
parent
1e6ec9ea89
commit
50b4d48552
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@ -29,26 +29,25 @@
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#include <scsi/scsi_cmnd.h>
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/**
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* bsg_destroy_job - routine to teardown/delete a bsg job
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* bsg_teardown_job - routine to teardown a bsg job
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* @job: bsg_job that is to be torn down
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*/
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static void bsg_destroy_job(struct kref *kref)
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static void bsg_teardown_job(struct kref *kref)
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{
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struct bsg_job *job = container_of(kref, struct bsg_job, kref);
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struct request *rq = job->req;
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blk_end_request_all(rq, BLK_STS_OK);
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put_device(job->dev); /* release reference for the request */
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kfree(job->request_payload.sg_list);
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kfree(job->reply_payload.sg_list);
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kfree(job);
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blk_end_request_all(rq, BLK_STS_OK);
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}
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void bsg_job_put(struct bsg_job *job)
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{
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kref_put(&job->kref, bsg_destroy_job);
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kref_put(&job->kref, bsg_teardown_job);
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}
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EXPORT_SYMBOL_GPL(bsg_job_put);
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@ -100,7 +99,7 @@ EXPORT_SYMBOL_GPL(bsg_job_done);
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*/
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static void bsg_softirq_done(struct request *rq)
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{
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struct bsg_job *job = rq->special;
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struct bsg_job *job = blk_mq_rq_to_pdu(rq);
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bsg_job_put(job);
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}
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@ -122,33 +121,20 @@ static int bsg_map_buffer(struct bsg_buffer *buf, struct request *req)
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}
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/**
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* bsg_create_job - create the bsg_job structure for the bsg request
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* bsg_prepare_job - create the bsg_job structure for the bsg request
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* @dev: device that is being sent the bsg request
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* @req: BSG request that needs a job structure
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*/
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static int bsg_create_job(struct device *dev, struct request *req)
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static int bsg_prepare_job(struct device *dev, struct request *req)
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{
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struct request *rsp = req->next_rq;
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struct request_queue *q = req->q;
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struct scsi_request *rq = scsi_req(req);
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struct bsg_job *job;
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struct bsg_job *job = blk_mq_rq_to_pdu(req);
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int ret;
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BUG_ON(req->special);
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job = kzalloc(sizeof(struct bsg_job) + q->bsg_job_size, GFP_KERNEL);
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if (!job)
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return -ENOMEM;
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req->special = job;
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job->req = req;
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if (q->bsg_job_size)
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job->dd_data = (void *)&job[1];
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job->request = rq->cmd;
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job->request_len = rq->cmd_len;
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job->reply = rq->sense;
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job->reply_len = SCSI_SENSE_BUFFERSIZE; /* Size of sense buffer
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* allocated */
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if (req->bio) {
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ret = bsg_map_buffer(&job->request_payload, req);
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if (ret)
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@ -187,7 +173,6 @@ static void bsg_request_fn(struct request_queue *q)
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{
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struct device *dev = q->queuedata;
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struct request *req;
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struct bsg_job *job;
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int ret;
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if (!get_device(dev))
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@ -199,7 +184,7 @@ static void bsg_request_fn(struct request_queue *q)
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break;
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spin_unlock_irq(q->queue_lock);
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ret = bsg_create_job(dev, req);
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ret = bsg_prepare_job(dev, req);
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if (ret) {
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scsi_req(req)->result = ret;
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blk_end_request_all(req, BLK_STS_OK);
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@ -207,8 +192,7 @@ static void bsg_request_fn(struct request_queue *q)
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continue;
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}
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job = req->special;
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ret = q->bsg_job_fn(job);
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ret = q->bsg_job_fn(blk_mq_rq_to_pdu(req));
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spin_lock_irq(q->queue_lock);
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if (ret)
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break;
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@ -219,6 +203,35 @@ static void bsg_request_fn(struct request_queue *q)
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spin_lock_irq(q->queue_lock);
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}
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static int bsg_init_rq(struct request_queue *q, struct request *req, gfp_t gfp)
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{
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struct bsg_job *job = blk_mq_rq_to_pdu(req);
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struct scsi_request *sreq = &job->sreq;
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memset(job, 0, sizeof(*job));
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scsi_req_init(sreq);
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sreq->sense_len = SCSI_SENSE_BUFFERSIZE;
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sreq->sense = kzalloc(sreq->sense_len, gfp);
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if (!sreq->sense)
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return -ENOMEM;
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job->req = req;
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job->reply = sreq->sense;
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job->reply_len = sreq->sense_len;
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job->dd_data = job + 1;
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return 0;
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}
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static void bsg_exit_rq(struct request_queue *q, struct request *req)
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{
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struct bsg_job *job = blk_mq_rq_to_pdu(req);
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struct scsi_request *sreq = &job->sreq;
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kfree(sreq->sense);
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}
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/**
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* bsg_setup_queue - Create and add the bsg hooks so we can receive requests
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* @dev: device to attach bsg device to
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@ -235,7 +248,9 @@ struct request_queue *bsg_setup_queue(struct device *dev, char *name,
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q = blk_alloc_queue(GFP_KERNEL);
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if (!q)
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return ERR_PTR(-ENOMEM);
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q->cmd_size = sizeof(struct scsi_request);
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q->cmd_size = sizeof(struct bsg_job) + dd_job_size;
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q->init_rq_fn = bsg_init_rq;
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q->exit_rq_fn = bsg_exit_rq;
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q->request_fn = bsg_request_fn;
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ret = blk_init_allocated_queue(q);
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@ -243,7 +258,6 @@ struct request_queue *bsg_setup_queue(struct device *dev, char *name,
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goto out_cleanup_queue;
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q->queuedata = dev;
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q->bsg_job_size = dd_job_size;
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q->bsg_job_fn = job_fn;
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queue_flag_set_unlocked(QUEUE_FLAG_BIDI, q);
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queue_flag_set_unlocked(QUEUE_FLAG_SCSI_PASSTHROUGH, q);
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@ -568,7 +568,6 @@ struct request_queue {
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#if defined(CONFIG_BLK_DEV_BSG)
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bsg_job_fn *bsg_job_fn;
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int bsg_job_size;
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struct bsg_class_device bsg_dev;
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#endif
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@ -24,6 +24,7 @@
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#define _BLK_BSG_
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#include <linux/blkdev.h>
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#include <scsi/scsi_request.h>
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struct request;
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struct device;
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@ -37,6 +38,7 @@ struct bsg_buffer {
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};
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struct bsg_job {
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struct scsi_request sreq;
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struct device *dev;
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struct request *req;
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