linux-kernel - [PATCH 1/6] bitmap_parselist: don't calculate length of the input string

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Message-Id: <20190220083705.14050-2-ynorov@marvell.com>
Date:   Wed, 20 Feb 2019 11:37:00 +0300
From:   Yury Norov <yury.norov@...il.com>
To:     Andrew Morton <akpm@...ux-foundation.org>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Arnd Bergmann <arnd@...db.de>,
        Dmitry Torokhov <dmitry.torokhov@...il.com>,
        Kees Cook <keescook@...omium.org>,
        Matthew Wilcox <willy@...radead.org>,
        Michael Ellerman <mpe@...erman.id.au>,
        Rasmus Villemoes <linux@...musvillemoes.dk>,
        Tetsuo Handa <penguin-kernel@...ove.SAKURA.ne.jp>
Cc:     Yury Norov <ynorov@...vell.com>, linux-kernel@...r.kernel.org,
        Yury Norov <yury.norov@...il.com>
Subject: [PATCH 1/6] bitmap_parselist: don't calculate length of the input string

bitmap_parselist() calculates length of the input string before passing
it to the __bitmap_parselist(). But the end-of-line condition is checked
for every character in __bitmap_parselist() anyway. So doing it in wrapper
is a simple waste of time.

Signed-off-by: Yury Norov <ynorov@...vell.com>
---
 lib/bitmap.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/lib/bitmap.c b/lib/bitmap.c
index 98872e9025da..ad1fb7e6ad0e 100644
--- a/lib/bitmap.c
+++ b/lib/bitmap.c
@@ -614,10 +614,7 @@ static int __bitmap_parselist(const char *buf, unsigned int buflen,
 
 int bitmap_parselist(const char *bp, unsigned long *maskp, int nmaskbits)
 {
-	char *nl  = strchrnul(bp, '\n');
-	int len = nl - bp;
-
-	return __bitmap_parselist(bp, len, 0, maskp, nmaskbits);
+	return __bitmap_parselist(bp, UINT_MAX, 0, maskp, nmaskbits);
 }
 EXPORT_SYMBOL(bitmap_parselist);
 
-- 
2.17.1