| /* |
| * BSG helper library |
| * |
| * Copyright (C) 2008 James Smart, Emulex Corporation |
| * Copyright (C) 2011 Red Hat, Inc. All rights reserved. |
| * Copyright (C) 2011 Mike Christie |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License as published by |
| * the Free Software Foundation; either version 2 of the License, or |
| * (at your option) any later version. |
| * |
| * This program is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| * GNU General Public License for more details. |
| * |
| * You should have received a copy of the GNU General Public License |
| * along with this program; if not, write to the Free Software |
| * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
| * |
| */ |
| #include <linux/slab.h> |
| #include <linux/blkdev.h> |
| #include <linux/delay.h> |
| #include <linux/scatterlist.h> |
| #include <linux/bsg-lib.h> |
| #include <linux/export.h> |
| #include <scsi/scsi_cmnd.h> |
| |
| /** |
| * bsg_destroy_job - routine to teardown/delete a bsg job |
| * @job: bsg_job that is to be torn down |
| */ |
| static void bsg_destroy_job(struct kref *kref) |
| { |
| struct bsg_job *job = container_of(kref, struct bsg_job, kref); |
| |
| put_device(job->dev); /* release reference for the request */ |
| |
| kfree(job->request_payload.sg_list); |
| kfree(job->reply_payload.sg_list); |
| kfree(job); |
| } |
| |
| /** |
| * bsg_job_done - completion routine for bsg requests |
| * @job: bsg_job that is complete |
| * @result: job reply result |
| * @reply_payload_rcv_len: length of payload recvd |
| * |
| * The LLD should call this when the bsg job has completed. |
| */ |
| void bsg_job_done(struct bsg_job *job, int result, |
| unsigned int reply_payload_rcv_len) |
| { |
| struct request *req = job->req; |
| struct request *rsp = req->next_rq; |
| int err; |
| |
| err = job->req->errors = result; |
| if (err < 0) |
| /* we're only returning the result field in the reply */ |
| job->req->sense_len = sizeof(u32); |
| else |
| job->req->sense_len = job->reply_len; |
| /* we assume all request payload was transferred, residual == 0 */ |
| req->resid_len = 0; |
| |
| if (rsp) { |
| WARN_ON(reply_payload_rcv_len > rsp->resid_len); |
| |
| /* set reply (bidi) residual */ |
| rsp->resid_len -= min(reply_payload_rcv_len, rsp->resid_len); |
| } |
| blk_complete_request(req); |
| } |
| EXPORT_SYMBOL_GPL(bsg_job_done); |
| |
| /** |
| * bsg_softirq_done - softirq done routine for destroying the bsg requests |
| * @rq: BSG request that holds the job to be destroyed |
| */ |
| static void bsg_softirq_done(struct request *rq) |
| { |
| struct bsg_job *job = rq->special; |
| |
| blk_end_request_all(rq, rq->errors); |
| kref_put(&job->kref, bsg_destroy_job); |
| } |
| |
| static int bsg_map_buffer(struct bsg_buffer *buf, struct request *req) |
| { |
| size_t sz = (sizeof(struct scatterlist) * req->nr_phys_segments); |
| |
| BUG_ON(!req->nr_phys_segments); |
| |
| buf->sg_list = kzalloc(sz, GFP_KERNEL); |
| if (!buf->sg_list) |
| return -ENOMEM; |
| sg_init_table(buf->sg_list, req->nr_phys_segments); |
| buf->sg_cnt = blk_rq_map_sg(req->q, req, buf->sg_list); |
| buf->payload_len = blk_rq_bytes(req); |
| return 0; |
| } |
| |
| /** |
| * bsg_create_job - create the bsg_job structure for the bsg request |
| * @dev: device that is being sent the bsg request |
| * @req: BSG request that needs a job structure |
| */ |
| static int bsg_create_job(struct device *dev, struct request *req) |
| { |
| struct request *rsp = req->next_rq; |
| struct request_queue *q = req->q; |
| struct bsg_job *job; |
| int ret; |
| |
| BUG_ON(req->special); |
| |
| job = kzalloc(sizeof(struct bsg_job) + q->bsg_job_size, GFP_KERNEL); |
| if (!job) |
| return -ENOMEM; |
| |
| req->special = job; |
| job->req = req; |
| if (q->bsg_job_size) |
| job->dd_data = (void *)&job[1]; |
| job->request = req->cmd; |
| job->request_len = req->cmd_len; |
| job->reply = req->sense; |
| job->reply_len = SCSI_SENSE_BUFFERSIZE; /* Size of sense buffer |
| * allocated */ |
| if (req->bio) { |
| ret = bsg_map_buffer(&job->request_payload, req); |
| if (ret) |
| goto failjob_rls_job; |
| } |
| if (rsp && rsp->bio) { |
| ret = bsg_map_buffer(&job->reply_payload, rsp); |
| if (ret) |
| goto failjob_rls_rqst_payload; |
| } |
| job->dev = dev; |
| /* take a reference for the request */ |
| get_device(job->dev); |
| kref_init(&job->kref); |
| return 0; |
| |
| failjob_rls_rqst_payload: |
| kfree(job->request_payload.sg_list); |
| failjob_rls_job: |
| kfree(job); |
| return -ENOMEM; |
| } |
| |
| /** |
| * bsg_request_fn - generic handler for bsg requests |
| * @q: request queue to manage |
| * |
| * On error the create_bsg_job function should return a -Exyz error value |
| * that will be set to the req->errors. |
| * |
| * Drivers/subsys should pass this to the queue init function. |
| */ |
| void bsg_request_fn(struct request_queue *q) |
| { |
| struct device *dev = q->queuedata; |
| struct request *req; |
| struct bsg_job *job; |
| int ret; |
| |
| if (!get_device(dev)) |
| return; |
| |
| while (1) { |
| req = blk_fetch_request(q); |
| if (!req) |
| break; |
| spin_unlock_irq(q->queue_lock); |
| |
| ret = bsg_create_job(dev, req); |
| if (ret) { |
| req->errors = ret; |
| blk_end_request_all(req, ret); |
| spin_lock_irq(q->queue_lock); |
| continue; |
| } |
| |
| job = req->special; |
| ret = q->bsg_job_fn(job); |
| spin_lock_irq(q->queue_lock); |
| if (ret) |
| break; |
| } |
| |
| spin_unlock_irq(q->queue_lock); |
| put_device(dev); |
| spin_lock_irq(q->queue_lock); |
| } |
| EXPORT_SYMBOL_GPL(bsg_request_fn); |
| |
| /** |
| * bsg_setup_queue - Create and add the bsg hooks so we can receive requests |
| * @dev: device to attach bsg device to |
| * @q: request queue setup by caller |
| * @name: device to give bsg device |
| * @job_fn: bsg job handler |
| * @dd_job_size: size of LLD data needed for each job |
| * |
| * The caller should have setup the reuqest queue with bsg_request_fn |
| * as the request_fn. |
| */ |
| int bsg_setup_queue(struct device *dev, struct request_queue *q, |
| char *name, bsg_job_fn *job_fn, int dd_job_size) |
| { |
| int ret; |
| |
| q->queuedata = dev; |
| q->bsg_job_size = dd_job_size; |
| q->bsg_job_fn = job_fn; |
| queue_flag_set_unlocked(QUEUE_FLAG_BIDI, q); |
| blk_queue_softirq_done(q, bsg_softirq_done); |
| blk_queue_rq_timeout(q, BLK_DEFAULT_SG_TIMEOUT); |
| |
| ret = bsg_register_queue(q, dev, name, NULL); |
| if (ret) { |
| printk(KERN_ERR "%s: bsg interface failed to " |
| "initialize - register queue\n", dev->kobj.name); |
| return ret; |
| } |
| |
| return 0; |
| } |
| EXPORT_SYMBOL_GPL(bsg_setup_queue); |