block: Introduce request_queue.initialize_rq_fn()

Several block drivers need to initialize the driver-private request
data after having called blk_get_request() and before .prep_rq_fn()
is called, e.g. when submitting a REQ_OP_SCSI_* request. Avoid that
that initialization code has to be repeated after every
blk_get_request() call by adding new callback functions to struct
request_queue and to struct blk_mq_ops.

Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.com>
Cc: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Bart Van Assche 2017-06-20 11:15:40 -07:00 committed by Jens Axboe
parent cd6ce1482f
commit d280bab305
3 changed files with 19 additions and 4 deletions

View File

@ -1372,12 +1372,21 @@ static struct request *blk_old_get_request(struct request_queue *q,
struct request *blk_get_request(struct request_queue *q, unsigned int op,
gfp_t gfp_mask)
{
if (q->mq_ops)
return blk_mq_alloc_request(q, op,
struct request *req;
if (q->mq_ops) {
req = blk_mq_alloc_request(q, op,
(gfp_mask & __GFP_DIRECT_RECLAIM) ?
0 : BLK_MQ_REQ_NOWAIT);
else
return blk_old_get_request(q, op, gfp_mask);
if (!IS_ERR(req) && q->mq_ops->initialize_rq_fn)
q->mq_ops->initialize_rq_fn(req);
} else {
req = blk_old_get_request(q, op, gfp_mask);
if (!IS_ERR(req) && q->initialize_rq_fn)
q->initialize_rq_fn(req);
}
return req;
}
EXPORT_SYMBOL(blk_get_request);

View File

@ -144,6 +144,8 @@ struct blk_mq_ops {
init_request_fn *init_request;
exit_request_fn *exit_request;
reinit_request_fn *reinit_request;
/* Called from inside blk_get_request() */
void (*initialize_rq_fn)(struct request *rq);
map_queues_fn *map_queues;

View File

@ -410,8 +410,12 @@ struct request_queue {
rq_timed_out_fn *rq_timed_out_fn;
dma_drain_needed_fn *dma_drain_needed;
lld_busy_fn *lld_busy_fn;
/* Called just after a request is allocated */
init_rq_fn *init_rq_fn;
/* Called just before a request is freed */
exit_rq_fn *exit_rq_fn;
/* Called from inside blk_get_request() */
void (*initialize_rq_fn)(struct request *rq);
const struct blk_mq_ops *mq_ops;