All of lore.kernel.org
 help / color / mirror / Atom feed
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;

      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]

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20170912195213.GB17730@avx2 \
    --to=adobriyan@gmail.com \
    --cc=akpm@linux-foundation.org \
    --cc=linux-kernel@vger.kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.