* [RFC] block: change blk_check_merge_flags() implementation
@ 2015-11-20 10:55 yalin wang
0 siblings, 0 replies; only message in thread
From: yalin wang @ 2015-11-20 10:55 UTC (permalink / raw)
To: axboe, snitzer, tj, jack, shli, ross.zwisler, matthew.r.wilcox,
rafael.j.wysocki, yalin.wang2010, linux-kernel
Use XOR to chenk some flags in flags1 and flags2 if the same,
much faster on some platforms.
Signed-off-by: yalin wang <yalin.wang2010@gmail.com>
---
include/linux/blkdev.h | 11 +----------
1 file changed, 1 insertion(+), 10 deletions(-)
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index c401ecd..3d0f053 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -655,16 +655,7 @@ static inline bool rq_mergeable(struct request *rq)
static inline bool blk_check_merge_flags(unsigned int flags1,
unsigned int flags2)
{
- if ((flags1 & REQ_DISCARD) != (flags2 & REQ_DISCARD))
- return false;
-
- if ((flags1 & REQ_SECURE) != (flags2 & REQ_SECURE))
- return false;
-
- if ((flags1 & REQ_WRITE_SAME) != (flags2 & REQ_WRITE_SAME))
- return false;
-
- return true;
+ return !((flags1 ^ flags2) & (REQ_DISCARD | REQ_SECURE | REQ_WRITE_SAME));
}
static inline bool blk_write_same_mergeable(struct bio *a, struct bio *b)
--
1.9.1
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