Commit a3bd7756 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Jens Axboe
Browse files

blk-mq: remove blk_mq_wait_for_tags 



The current logic for blocking tag allocation is rather confusing, as we
first allocated and then free again a tag in blk_mq_wait_for_tags, just
to attempt a non-blocking allocation and then repeat if someone else
managed to grab the tag before us.

Instead change blk_mq_alloc_request_pinned to simply do a blocking tag
allocation itself and use the request we get back from it.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarJens Axboe <axboe@fb.com>
parent 5dee8577

block/blk-mq-tag.c

+0 −8
Original line number Diff line number Diff line
@@ -7,14 +7,6 @@ 
#include "blk-mq.h"

#include "blk-mq-tag.h"



void blk_mq_wait_for_tags(struct blk_mq_hw_ctx *hctx, bool reserved)

{

	int tag, zero = 0;



	tag = blk_mq_get_tag(hctx, &zero, __GFP_WAIT, reserved);

	blk_mq_put_tag(hctx, tag, &zero);

}



static bool bt_has_free_tags(struct blk_mq_bitmap_tags *bt)

{

	int i;

block/blk-mq-tag.h

+0 −1
Original line number Diff line number Diff line
@@ -49,7 +49,6 @@ extern struct blk_mq_tags *blk_mq_init_tags(unsigned int nr_tags, unsigned int r 
extern void blk_mq_free_tags(struct blk_mq_tags *tags);



extern unsigned int blk_mq_get_tag(struct blk_mq_hw_ctx *hctx, unsigned int *last_tag, gfp_t gfp, bool reserved);

extern void blk_mq_wait_for_tags(struct blk_mq_hw_ctx *hctx, bool reserved);

extern void blk_mq_put_tag(struct blk_mq_hw_ctx *hctx, unsigned int tag, unsigned int *last_tag);

extern bool blk_mq_has_free_tags(struct blk_mq_tags *tags);

extern ssize_t blk_mq_tag_sysfs_show(struct blk_mq_tags *tags, char *page);

block/blk-mq.c

+6 −7
Original line number Diff line number Diff line
@@ -264,31 +264,30 @@ __blk_mq_alloc_request(struct request_queue *q, struct blk_mq_hw_ctx *hctx, 
	return NULL;

}





static struct request *blk_mq_alloc_request_pinned(struct request_queue *q,

						   int rw, gfp_t gfp,

						   bool reserved)

{

	bool gfp_mask = gfp & ~__GFP_WAIT;

	struct request *rq;



	do {

		struct blk_mq_ctx *ctx = blk_mq_get_ctx(q);

		struct blk_mq_hw_ctx *hctx = q->mq_ops->map_queue(q, ctx->cpu);



		rq = __blk_mq_alloc_request(q, hctx, ctx, rw, gfp & ~__GFP_WAIT,

		rq = __blk_mq_alloc_request(q, hctx, ctx, rw, gfp_mask,

						reserved);

		if (rq)

			break;



		if (gfp & __GFP_WAIT) {

			__blk_mq_run_hw_queue(hctx);

			blk_mq_put_ctx(ctx);

		} else {

		if (!(gfp & __GFP_WAIT)) {

			blk_mq_put_ctx(ctx);

			break;

		}



		blk_mq_wait_for_tags(hctx, reserved);

		__blk_mq_run_hw_queue(hctx);

		blk_mq_put_ctx(ctx);

		gfp_mask = gfp;

	} while (1);



	return rq;

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