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232 lines
6.0 KiB
232 lines
6.0 KiB
/* |
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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 bsg_job *job) |
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{ |
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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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/** |
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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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blk_end_request_all(rq, rq->errors); |
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bsg_destroy_job(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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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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{ |
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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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