From 75d6e175fc511e95ae3eb8f708680133bc211ed3 Mon Sep 17 00:00:00 2001 From: Ming Lei Date: Thu, 2 Aug 2018 18:23:26 +0800 Subject: [PATCH] blk-mq: fix updating tags depth The passed 'nr' from userspace represents the total depth, meantime inside 'struct blk_mq_tags', 'nr_tags' stores the total tag depth, and 'nr_reserved_tags' stores the reserved part. There are two issues in blk_mq_tag_update_depth() now: 1) for growing tags, we should have used the passed 'nr', and keep the number of reserved tags not changed. 2) the passed 'nr' should have been used for checking against 'tags->nr_tags', instead of number of the normal part. This patch fixes the above two cases, and avoids kernel crash caused by wrong resizing sbitmap queue. Cc: "Ewan D. Milne" Cc: Christoph Hellwig Cc: Bart Van Assche Cc: Omar Sandoval Tested by: Marco Patalano Signed-off-by: Ming Lei Signed-off-by: Jens Axboe --- block/blk-mq-tag.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/block/blk-mq-tag.c b/block/blk-mq-tag.c index 09b2ee6694fb..c43b3398d7b4 100644 --- a/block/blk-mq-tag.c +++ b/block/blk-mq-tag.c @@ -399,8 +399,6 @@ int blk_mq_tag_update_depth(struct blk_mq_hw_ctx *hctx, if (tdepth <= tags->nr_reserved_tags) return -EINVAL; - tdepth -= tags->nr_reserved_tags; - /* * If we are allowed to grow beyond the original size, allocate * a new set of tags before freeing the old one. @@ -420,7 +418,8 @@ int blk_mq_tag_update_depth(struct blk_mq_hw_ctx *hctx, if (tdepth > 16 * BLKDEV_MAX_RQ) return -EINVAL; - new = blk_mq_alloc_rq_map(set, hctx->queue_num, tdepth, 0); + new = blk_mq_alloc_rq_map(set, hctx->queue_num, tdepth, + tags->nr_reserved_tags); if (!new) return -ENOMEM; ret = blk_mq_alloc_rqs(set, new, hctx->queue_num, tdepth); @@ -437,7 +436,8 @@ int blk_mq_tag_update_depth(struct blk_mq_hw_ctx *hctx, * Don't need (or can't) update reserved tags here, they * remain static and should never need resizing. */ - sbitmap_queue_resize(&tags->bitmap_tags, tdepth); + sbitmap_queue_resize(&tags->bitmap_tags, + tdepth - tags->nr_reserved_tags); } return 0; -- 2.30.2