Messages in this thread Patch in this message | | | Subject | [PATCH] block: fix request sorting at unplug | From | Konstantin Khlebnikov <> | Date | Sat, 2 Apr 2011 19:37:37 +0400 |
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Comparison function for list_sort() must be anticommutative, otherwise it is not sorting in ordinary meaning.
But fortunately list_sort() always check ((*cmp)(priv, a, b) <= 0) it not distinguish negative and zero, so comparison function can implement only less-or-equal instead of full three-way comparison.
Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org> --- block/blk-core.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/block/blk-core.c b/block/blk-core.c index e0a0623..5e151d2 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -2665,7 +2665,7 @@ static int plug_rq_cmp(void *priv, struct list_head *a, struct list_head *b) struct request *rqa = container_of(a, struct request, queuelist); struct request *rqb = container_of(b, struct request, queuelist); - return !(rqa->q == rqb->q); + return !(rqa->q <= rqb->q); } static void flush_plug_list(struct blk_plug *plug)
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