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>
diff --git a/block/blk-core.c b/block/blk-core.c
index 21f6f10..0998902 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -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);
diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index 3077714..366b83c 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -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;
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index e21dd89..9a36164 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -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;
