Commit 013a7f95 authored by Jens Axboe's avatar Jens Axboe
Browse files

block: provide helpers for rq_list manipulation 



Instead of open-coding the list additions, traversal, and removal,
provide a basic set of helpers.

Suggested-by: default avatarChristoph Hellwig <hch@infradead.org>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent afd7de03

block/blk-mq.c

+5 −14
Original line number Diff line number Diff line
@@ -404,17 +404,11 @@ __blk_mq_alloc_requests_batch(struct blk_mq_alloc_data *data, 
		tag = tag_offset + i;

		tags &= ~(1UL << i);

		rq = blk_mq_rq_ctx_init(data, tag, alloc_time_ns);

		rq->rq_next = *data->cached_rq;

		*data->cached_rq = rq;

		rq_list_add(data->cached_rq, rq);

	}

	data->nr_tags -= nr;



	if (!data->cached_rq)

		return NULL;



	rq = *data->cached_rq;

	*data->cached_rq = rq->rq_next;

	return rq;

	return rq_list_pop(data->cached_rq);

}



static struct request *__blk_mq_alloc_requests(struct blk_mq_alloc_data *data)
@@ -622,11 +616,9 @@ EXPORT_SYMBOL_GPL(blk_mq_free_request); 


void blk_mq_free_plug_rqs(struct blk_plug *plug)

{

	while (plug->cached_rq) {

	struct request *rq;



		rq = plug->cached_rq;

		plug->cached_rq = rq->rq_next;

	while ((rq = rq_list_pop(&plug->cached_rq)) != NULL) {

		percpu_ref_get(&rq->q->q_usage_counter);

		blk_mq_free_request(rq);

	}
@@ -2418,8 +2410,7 @@ void blk_mq_submit_bio(struct bio *bio) 


	plug = blk_mq_plug(q, bio);

	if (plug && plug->cached_rq) {

		rq = plug->cached_rq;

		plug->cached_rq = rq->rq_next;

		rq = rq_list_pop(&plug->cached_rq);

		INIT_LIST_HEAD(&rq->queuelist);

	} else {

		struct blk_mq_alloc_data data = {

include/linux/blkdev.h

+29 −0
Original line number Diff line number Diff line
@@ -1298,4 +1298,33 @@ int fsync_bdev(struct block_device *bdev); 
int freeze_bdev(struct block_device *bdev);

int thaw_bdev(struct block_device *bdev);



#define rq_list_add(listptr, rq)	do {		\

	(rq)->rq_next = *(listptr);			\

	*(listptr) = rq;				\

} while (0)



#define rq_list_pop(listptr)				\

({							\

	struct request *__req = NULL;			\

	if ((listptr) && *(listptr))	{		\

		__req = *(listptr);			\

		*(listptr) = __req->rq_next;		\

	}						\

	__req;						\

})



#define rq_list_peek(listptr)				\

({							\

	struct request *__req = NULL;			\

	if ((listptr) && *(listptr))			\

		__req = *(listptr);			\

	__req;						\

})



#define rq_list_for_each(listptr, pos)			\

	for (pos = rq_list_peek((listptr)); pos; pos = rq_list_next(pos)) \



#define rq_list_next(rq)	(rq)->rq_next

#define rq_list_empty(list)	((list) == (struct request *) NULL)



#endif /* _LINUX_BLKDEV_H */