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![Christoph Hellwig](/assets/img/avatar_default.png)
This passes on the scsi_cmnd result field to users of passthrough requests. Currently we abuse req->errors for this purpose, but that field will go away in its current form. Note that the old IDE code abuses the errors field in very creative ways and stores all kinds of different values in it. I didn't dare to touch this magic, so the abuses are brought forward 1:1. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: Bart Van Assche <Bart.VanAssche@sandisk.com> Signed-off-by: Jens Axboe <axboe@fb.com>
264 lines
6.7 KiB
C
264 lines
6.7 KiB
C
/*
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* BSG helper library
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*
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* Copyright (C) 2008 James Smart, Emulex Corporation
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* Copyright (C) 2011 Red Hat, Inc. All rights reserved.
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* Copyright (C) 2011 Mike Christie
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*
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*/
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#include <linux/slab.h>
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#include <linux/blkdev.h>
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#include <linux/delay.h>
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#include <linux/scatterlist.h>
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#include <linux/bsg-lib.h>
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#include <linux/export.h>
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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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* @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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{
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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, scsi_req(rq)->result);
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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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}
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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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}
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EXPORT_SYMBOL_GPL(bsg_job_put);
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int bsg_job_get(struct bsg_job *job)
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{
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return kref_get_unless_zero(&job->kref);
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}
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EXPORT_SYMBOL_GPL(bsg_job_get);
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/**
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* bsg_job_done - completion routine for bsg requests
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* @job: bsg_job that is complete
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* @result: job reply result
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* @reply_payload_rcv_len: length of payload recvd
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*
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* The LLD should call this when the bsg job has completed.
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*/
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void bsg_job_done(struct bsg_job *job, int result,
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unsigned int reply_payload_rcv_len)
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{
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struct request *req = job->req;
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struct request *rsp = req->next_rq;
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struct scsi_request *rq = scsi_req(req);
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int err;
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err = scsi_req(job->req)->result = result;
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if (err < 0)
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/* we're only returning the result field in the reply */
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rq->sense_len = sizeof(u32);
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else
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rq->sense_len = job->reply_len;
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/* we assume all request payload was transferred, residual == 0 */
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rq->resid_len = 0;
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if (rsp) {
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WARN_ON(reply_payload_rcv_len > scsi_req(rsp)->resid_len);
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/* set reply (bidi) residual */
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scsi_req(rsp)->resid_len -=
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min(reply_payload_rcv_len, scsi_req(rsp)->resid_len);
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}
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blk_complete_request(req);
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}
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EXPORT_SYMBOL_GPL(bsg_job_done);
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/**
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* bsg_softirq_done - softirq done routine for destroying the bsg requests
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* @rq: BSG request that holds the job to be destroyed
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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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bsg_job_put(job);
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}
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static int bsg_map_buffer(struct bsg_buffer *buf, struct request *req)
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{
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size_t sz = (sizeof(struct scatterlist) * req->nr_phys_segments);
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BUG_ON(!req->nr_phys_segments);
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buf->sg_list = kzalloc(sz, GFP_KERNEL);
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if (!buf->sg_list)
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return -ENOMEM;
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sg_init_table(buf->sg_list, req->nr_phys_segments);
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scsi_req(req)->resid_len = blk_rq_bytes(req);
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buf->sg_cnt = blk_rq_map_sg(req->q, req, buf->sg_list);
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buf->payload_len = blk_rq_bytes(req);
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return 0;
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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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* @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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{
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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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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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goto failjob_rls_job;
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}
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if (rsp && rsp->bio) {
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ret = bsg_map_buffer(&job->reply_payload, rsp);
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if (ret)
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goto failjob_rls_rqst_payload;
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}
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job->dev = dev;
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/* take a reference for the request */
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get_device(job->dev);
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kref_init(&job->kref);
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return 0;
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failjob_rls_rqst_payload:
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kfree(job->request_payload.sg_list);
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failjob_rls_job:
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kfree(job);
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return -ENOMEM;
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}
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/**
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* bsg_request_fn - generic handler for bsg requests
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* @q: request queue to manage
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*
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* On error the create_bsg_job function should return a -Exyz error value
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* that will be set to ->result.
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*
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* Drivers/subsys should pass this to the queue init function.
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*/
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static void bsg_request_fn(struct request_queue *q)
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__releases(q->queue_lock)
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__acquires(q->queue_lock)
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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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return;
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while (1) {
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req = blk_fetch_request(q);
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if (!req)
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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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if (ret) {
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scsi_req(req)->result = ret;
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blk_end_request_all(req, ret);
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spin_lock_irq(q->queue_lock);
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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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spin_lock_irq(q->queue_lock);
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if (ret)
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break;
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}
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spin_unlock_irq(q->queue_lock);
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put_device(dev);
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spin_lock_irq(q->queue_lock);
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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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* @name: device to give bsg device
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* @job_fn: bsg job handler
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* @dd_job_size: size of LLD data needed for each job
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*/
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struct request_queue *bsg_setup_queue(struct device *dev, char *name,
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bsg_job_fn *job_fn, int dd_job_size)
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{
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struct request_queue *q;
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int ret;
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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->request_fn = bsg_request_fn;
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ret = blk_init_allocated_queue(q);
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if (ret)
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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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blk_queue_softirq_done(q, bsg_softirq_done);
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blk_queue_rq_timeout(q, BLK_DEFAULT_SG_TIMEOUT);
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ret = bsg_register_queue(q, dev, name, NULL);
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if (ret) {
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printk(KERN_ERR "%s: bsg interface failed to "
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"initialize - register queue\n", dev->kobj.name);
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goto out_cleanup_queue;
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}
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return q;
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out_cleanup_queue:
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blk_cleanup_queue(q);
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return ERR_PTR(ret);
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}
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EXPORT_SYMBOL_GPL(bsg_setup_queue);
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