From: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>
To: Jens Axboe <axboe@kernel.dk>, LKML <linux-kernel@vger.kernel.org>
Cc: <raghavendra.kt@linux.vnet.ibm.com>
Subject: [PATCH] block:Remove extra condition in end of disk check
Date: Sun, 23 Jun 2013 22:47:11 +0530 [thread overview]
Message-ID: <20130623171711.7127.16248.sendpatchset@codeblue.in.ibm.com> (raw)
From: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>
Since #sector is always positive the reduced condition check
encompasses maxsector < nr_sectors check.
Signed-off-by: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>
---
An userspace program looping with:
maxsector - 0-9999
nr_sector - 0-999
sector - 0-999 gave 6.4% improvement with new condition though I agree that
it is not the best way to test it perhaps :)
diff --git a/block/blk-core.c b/block/blk-core.c
index 33c33bc..4a78583 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -1656,7 +1656,7 @@ static inline int bio_check_eod(struct bio *bio, unsigned int nr_sectors)
if (maxsector) {
sector_t sector = bio->bi_sector;
- if (maxsector < nr_sectors || maxsector - nr_sectors < sector) {
+ if (maxsector - nr_sectors < sector) {
/*
* This may well happen - the kernel calls bread()
* without checking the size of the device, e.g., when
next reply other threads:[~2013-06-23 17:13 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-06-23 17:17 Raghavendra K T [this message]
2013-06-24 13:50 ` [PATCH] block:Remove extra condition in end of disk check Raghavendra K T
2013-06-24 22:51 ` Tejun Heo
2013-06-25 5:10 ` Raghavendra K T
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