252 lines
6.4 KiB
C
252 lines
6.4 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, rq->errors);
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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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int err;
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err = job->req->errors = 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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job->req->sense_len = sizeof(u32);
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else
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job->req->sense_len = job->reply_len;
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/* we assume all request payload was transferred, residual == 0 */
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req->resid_len = 0;
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if (rsp) {
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WARN_ON(reply_payload_rcv_len > rsp->resid_len);
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/* set reply (bidi) residual */
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rsp->resid_len -= min(reply_payload_rcv_len, 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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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 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 = req->cmd;
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job->request_len = req->cmd_len;
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job->reply = req->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 the req->errors.
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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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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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req->errors = 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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EXPORT_SYMBOL_GPL(bsg_request_fn);
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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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* @q: request queue setup by caller
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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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* The caller should have setup the reuqest queue with bsg_request_fn
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* as the request_fn.
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*/
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int bsg_setup_queue(struct device *dev, struct request_queue *q,
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char *name, bsg_job_fn *job_fn, int dd_job_size)
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{
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int ret;
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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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return ret;
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}
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return 0;
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}
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EXPORT_SYMBOL_GPL(bsg_setup_queue);
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