/*
* 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 bsg_job *job)
{
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);
bsg_destroy_job(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);
return 0;
failjob_rls_rqst_payload:
kfree(job->request_payload.sg_list);
failjob_rls_job:
kfree(job);
return -ENOMEM;
}
/*
* bsg_goose_queue - restart queue in case it was stopped
* @q: request q to be restarted
*/
void bsg_goose_queue(struct request_queue *q)
{
if (!q)
return;
blk_run_queue_async(q);
}
EXPORT_SYMBOL_GPL(bsg_goose_queue);
/**
* 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);
/**
* bsg_remove_queue - Deletes the bsg dev from the q
* @q: the request_queue that is to be torn down.
*
* Notes:
* Before unregistering the queue empty any requests that are blocked
*/
void bsg_remove_queue(struct request_queue *q)
{
struct request *req; /* block request */
int counts; /* totals for request_list count and starved */
if (!q)
return;
/* Stop taking in new requests */
spin_lock_irq(q->queue_lock);
blk_stop_queue(q);
/* drain all requests in the queue */
while (1) {
/* need the lock to fetch a request
* this may fetch the same reqeust as the previous pass
*/
req = blk_fetch_request(q);
/* save requests in use and starved */
counts = q->rq.count[0] + q->rq.count[1] +
q->rq.starved[0] + q->rq.starved[1];
spin_unlock_irq(q->queue_lock);
/* any requests still outstanding? */
if (counts == 0)
break;
/* This may be the same req as the previous iteration,
* always send the blk_end_request_all after a prefetch.
* It is not okay to not end the request because the
* prefetch started the request.
*/
if (req) {
/* return -ENXIO to indicate that this queue is
* going away
*/
req->errors = -ENXIO;
blk_end_request_all(req, -ENXIO);
}
msleep(200); /* allow bsg to possibly finish */
spin_lock_irq(q->queue_lock);
}
bsg_unregister_queue(q);
}
EXPORT_SYMBOL_GPL(bsg_remove_queue);
