linux-kernel - [PATCH v2 3/4] lib/vsprintf.c: Remove SPECIAL handling in pointer()

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Date:	Wed, 30 Sep 2015 17:30:50 +0200
From:	Rasmus Villemoes <linux@...musvillemoes.dk>
To:	Andrew Morton <akpm@...ux-foundation.org>
Cc:	Tejun Heo <tj@...nel.org>,
	Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
	linux-kernel@...r.kernel.org, Kees Cook <keescook@...omium.org>,
	Joe Perches <joe@...ches.com>,
	Rasmus Villemoes <linux@...musvillemoes.dk>
Subject: [PATCH v2 3/4] lib/vsprintf.c: Remove SPECIAL handling in pointer()

As a quick

   git grep -E '%[ +0#-]*#[ +0#-]*(\*|[0-9]+)?(\.(\*|[0-9]+)?)?p'

shows, nobody uses the # flag with %p. Should one try to do so, one
will be met with

  warning: `#' flag used with ‘%p’ gnu_printf format [-Wformat]

(POSIX and C99 both say "... For other conversion specifiers, the
behavior is undefined.". Obviously, the kernel can choose to define
the behaviour however it wants, but as long as gcc issues that
warning, users are unlikely to show up.)

Since default_width is effectively always 2*sizeof(void*), we can
simplify the prologue of pointer() and save a few instructions.

Signed-off-by: Rasmus Villemoes <linux@...musvillemoes.dk>
---
v2: reword slightly, refer to POSIX/C99.

 lib/vsprintf.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index 03fa10b4be96..98b0d7be3fb7 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -1457,7 +1457,7 @@ static noinline_for_stack
 char *pointer(const char *fmt, char *buf, char *end, void *ptr,
 	      struct printf_spec spec)
 {
-	int default_width = 2 * sizeof(void *) + (spec.flags & SPECIAL ? 2 : 0);
+	const int default_width = 2 * sizeof(void *);
 
 	if (!ptr && *fmt != 'K') {
 		/*
-- 
2.1.3

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