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Commit 6a15674d authored by Bart Van Assche's avatar Bart Van Assche Committed by Jens Axboe
Browse files

block: Introduce blk_get_request_flags() 



A side effect of this patch is that the GFP mask that is passed to
several allocation functions in the legacy block layer is changed
from GFP_KERNEL into __GFP_DIRECT_RECLAIM.

Signed-off-by: default avatarBart Van Assche <bart.vanassche@wdc.com>
Reviewed-by: default avatarHannes Reinecke <hare@suse.com>
Tested-by: default avatarMartin Steigerwald <martin@lichtvoll.de>
Tested-by: default avatarOleksandr Natalenko <oleksandr@natalenko.name>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Ming Lei <ming.lei@redhat.com>
Cc: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 055f6e18

block/blk-core.c

+35 −15
Original line number Diff line number Diff line
@@ -1160,7 +1160,7 @@ int blk_update_nr_requests(struct request_queue *q, unsigned int nr) 
 * @rl: request list to allocate from

 * @op: operation and flags

 * @bio: bio to allocate request for (can be %NULL)

 * @gfp_mask: allocation mask

 * @flags: BLQ_MQ_REQ_* flags

 *

 * Get a free request from @q.  This function may fail under memory

 * pressure or if @q is dead.
@@ -1170,7 +1170,7 @@ int blk_update_nr_requests(struct request_queue *q, unsigned int nr) 
 * Returns request pointer on success, with @q->queue_lock *not held*.

 */

static struct request *__get_request(struct request_list *rl, unsigned int op,

		struct bio *bio, gfp_t gfp_mask)

				     struct bio *bio, unsigned int flags)

{

	struct request_queue *q = rl->q;

	struct request *rq;
@@ -1179,6 +1179,8 @@ static struct request *__get_request(struct request_list *rl, unsigned int op, 
	struct io_cq *icq = NULL;

	const bool is_sync = op_is_sync(op);

	int may_queue;

	gfp_t gfp_mask = flags & BLK_MQ_REQ_NOWAIT ? GFP_ATOMIC :

			 __GFP_DIRECT_RECLAIM;

	req_flags_t rq_flags = RQF_ALLOCED;



	lockdep_assert_held(q->queue_lock);
@@ -1339,7 +1341,7 @@ static struct request *__get_request(struct request_list *rl, unsigned int op, 
 * @q: request_queue to allocate request from

 * @op: operation and flags

 * @bio: bio to allocate request for (can be %NULL)

 * @gfp_mask: allocation mask

 * @flags: BLK_MQ_REQ_* flags.

 *

 * Get a free request from @q.  If %__GFP_DIRECT_RECLAIM is set in @gfp_mask,

 * this function keeps retrying under memory pressure and fails iff @q is dead.
@@ -1349,7 +1351,7 @@ static struct request *__get_request(struct request_list *rl, unsigned int op, 
 * Returns request pointer on success, with @q->queue_lock *not held*.

 */

static struct request *get_request(struct request_queue *q, unsigned int op,

		struct bio *bio, gfp_t gfp_mask)

				   struct bio *bio, unsigned int flags)

{

	const bool is_sync = op_is_sync(op);

	DEFINE_WAIT(wait);
@@ -1361,7 +1363,7 @@ static struct request *get_request(struct request_queue *q, unsigned int op, 


	rl = blk_get_rl(q, bio);	/* transferred to @rq on success */

retry:

	rq = __get_request(rl, op, bio, gfp_mask);

	rq = __get_request(rl, op, bio, flags);

	if (!IS_ERR(rq))

		return rq;
@@ -1370,7 +1372,7 @@ static struct request *get_request(struct request_queue *q, unsigned int op, 
		return ERR_PTR(-EAGAIN);

	}



	if (!gfpflags_allow_blocking(gfp_mask) || unlikely(blk_queue_dying(q))) {

	if ((flags & BLK_MQ_REQ_NOWAIT) || unlikely(blk_queue_dying(q))) {

		blk_put_rl(rl);

		return rq;

	}
@@ -1397,10 +1399,13 @@ static struct request *get_request(struct request_queue *q, unsigned int op, 
	goto retry;

}



/* flags: BLK_MQ_REQ_PREEMPT and/or BLK_MQ_REQ_NOWAIT. */

static struct request *blk_old_get_request(struct request_queue *q,

					   unsigned int op, gfp_t gfp_mask)

					   unsigned int op, unsigned int flags)

{

	struct request *rq;

	gfp_t gfp_mask = flags & BLK_MQ_REQ_NOWAIT ? GFP_ATOMIC :

			 __GFP_DIRECT_RECLAIM;

	int ret = 0;



	WARN_ON_ONCE(q->mq_ops);
@@ -1413,7 +1418,7 @@ static struct request *blk_old_get_request(struct request_queue *q, 
	if (ret)

		return ERR_PTR(ret);

	spin_lock_irq(q->queue_lock);

	rq = get_request(q, op, NULL, gfp_mask);

	rq = get_request(q, op, NULL, flags);

	if (IS_ERR(rq)) {

		spin_unlock_irq(q->queue_lock);

		blk_queue_exit(q);
@@ -1427,25 +1432,40 @@ static struct request *blk_old_get_request(struct request_queue *q, 
	return rq;

}



struct request *blk_get_request(struct request_queue *q, unsigned int op,

				gfp_t gfp_mask)

/**

 * blk_get_request_flags - allocate a request

 * @q: request queue to allocate a request for

 * @op: operation (REQ_OP_*) and REQ_* flags, e.g. REQ_SYNC.

 * @flags: BLK_MQ_REQ_* flags, e.g. BLK_MQ_REQ_NOWAIT.

 */

struct request *blk_get_request_flags(struct request_queue *q, unsigned int op,

				      unsigned int flags)

{

	struct request *req;



	WARN_ON_ONCE(op & REQ_NOWAIT);

	WARN_ON_ONCE(flags & ~BLK_MQ_REQ_NOWAIT);



	if (q->mq_ops) {

		req = blk_mq_alloc_request(q, op,

			(gfp_mask & __GFP_DIRECT_RECLAIM) ?

				0 : BLK_MQ_REQ_NOWAIT);

		req = blk_mq_alloc_request(q, op, flags);

		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);

		req = blk_old_get_request(q, op, flags);

		if (!IS_ERR(req) && q->initialize_rq_fn)

			q->initialize_rq_fn(req);

	}



	return req;

}

EXPORT_SYMBOL(blk_get_request_flags);



struct request *blk_get_request(struct request_queue *q, unsigned int op,

				gfp_t gfp_mask)

{

	return blk_get_request_flags(q, op, gfp_mask & __GFP_DIRECT_RECLAIM ?

				     0 : BLK_MQ_REQ_NOWAIT);

}

EXPORT_SYMBOL(blk_get_request);



/**
@@ -1871,7 +1891,7 @@ static blk_qc_t blk_queue_bio(struct request_queue *q, struct bio *bio) 
	 * Returns with the queue unlocked.

	 */

	blk_queue_enter_live(q);

	req = get_request(q, bio->bi_opf, bio, GFP_NOIO);

	req = get_request(q, bio->bi_opf, bio, 0);

	if (IS_ERR(req)) {

		blk_queue_exit(q);

		__wbt_done(q->rq_wb, wb_acct);

include/linux/blkdev.h

+3 −0
Original line number Diff line number Diff line
@@ -927,6 +927,9 @@ extern void blk_rq_init(struct request_queue *q, struct request *rq); 
extern void blk_init_request_from_bio(struct request *req, struct bio *bio);

extern void blk_put_request(struct request *);

extern void __blk_put_request(struct request_queue *, struct request *);

extern struct request *blk_get_request_flags(struct request_queue *,

					     unsigned int op,

					     unsigned int flags);

extern struct request *blk_get_request(struct request_queue *, unsigned int op,

				       gfp_t gfp_mask);

extern void blk_requeue_request(struct request_queue *, struct request *);