Commit 569fd0ce authored by Jens Axboe's avatar Jens Axboe
Browse files

blk-mq: fix iteration of busy bitmap 



Commit 889fa31f was a bit too eager in reducing the loop count,
so we ended up missing queues in some configurations. Ensure that
our division rounds up, so that's not the case.

Reported-by: default avatarGuenter Roeck <linux@roeck-us.net>
Fixes: 889fa31f ("blk-mq: reduce unnecessary software queue looping")
Signed-off-by: default avatarJens Axboe <axboe@fb.com>
parent 54e514b9

block/blk-mq.c

+3 −3
Original line number Diff line number Diff line
@@ -41,7 +41,7 @@ static bool blk_mq_hctx_has_pending(struct blk_mq_hw_ctx *hctx) 
{

	unsigned int i;



	for (i = 0; i < hctx->ctx_map.map_size; i++)

	for (i = 0; i < hctx->ctx_map.size; i++)

		if (hctx->ctx_map.map[i].word)

			return true;
@@ -730,7 +730,7 @@ static void flush_busy_ctxs(struct blk_mq_hw_ctx *hctx, struct list_head *list) 
	struct blk_mq_ctx *ctx;

	int i;



	for (i = 0; i < hctx->ctx_map.map_size; i++) {

	for (i = 0; i < hctx->ctx_map.size; i++) {

		struct blk_align_bitmap *bm = &hctx->ctx_map.map[i];

		unsigned int off, bit;
@@ -1818,7 +1818,7 @@ static void blk_mq_map_swqueue(struct request_queue *q) 
		 * This is more accurate and more efficient than looping

		 * over all possibly mapped software queues.

		 */

		map->map_size = hctx->nr_ctx / map->bits_per_word;

		map->size = DIV_ROUND_UP(hctx->nr_ctx, map->bits_per_word);



		/*

		 * Initialize batch roundrobin counts

include/linux/blk-mq.h

+1 −1
Original line number Diff line number Diff line
@@ -13,7 +13,7 @@ struct blk_mq_cpu_notifier { 
};



struct blk_mq_ctxmap {

	unsigned int map_size;

	unsigned int size;

	unsigned int bits_per_word;

	struct blk_align_bitmap *map;

};

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