From: Alexey Dobriyan <adobriyan@gmail.com>
To: akpm@linux-foundation.org
Cc: linux-kernel@vger.kernel.org
Subject: [PATCH 2/2] proc: use do-while in name_to_int()
Date: Tue, 12 Sep 2017 22:52:13 +0300 [thread overview]
Message-ID: <20170912195213.GB17730@avx2> (raw)
In-Reply-To: <20170912194850.GA17730@avx2>
Gcc doesn't know that "len" is guaranteed to be >=1 by dcache and
generates standard while-loop prologue duplicating loop condition.
add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-27 (-27)
function old new delta
name_to_int 104 77 -27
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
---
fs/proc/util.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--- a/fs/proc/util.c
+++ b/fs/proc/util.c
@@ -8,7 +8,7 @@ unsigned name_to_int(const struct qstr *qstr)
if (len > 1 && *name == '0')
goto out;
- while (len-- > 0) {
+ do {
unsigned c = *name++ - '0';
if (c > 9)
goto out;
@@ -16,7 +16,7 @@ unsigned name_to_int(const struct qstr *qstr)
goto out;
n *= 10;
n += c;
- }
+ } while (--len > 0);
return n;
out:
return ~0U;
prev parent reply other threads:[~2017-09-12 19:52 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-12 19:48 [PATCH 1/2] proc: uninline name_to_int() Alexey Dobriyan
2017-09-12 19:52 ` Alexey Dobriyan [this message]
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