linux-kernel - [PATCH/RFC 0/2] lib: string: Remove duplicated function

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Message-Id: <1409124962-11527-1-git-send-email-linux@rasmusvillemoes.dk>
Date:	Wed, 27 Aug 2014 09:36:00 +0200
From:	Rasmus Villemoes <linux@...musvillemoes.dk>
To:	Grant Likely <grant.likely@...aro.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Andi Kleen <ak@...ux.intel.com>,
	Dan Carpenter <dan.carpenter@...cle.com>,
	"H. Peter Anvin" <hpa@...ux.intel.com>
Cc:	linux-kernel@...r.kernel.org,
	Rasmus Villemoes <linux@...musvillemoes.dk>
Subject: [PATCH/RFC 0/2] lib: string: Remove duplicated function

lib/string.c contains two functions, strnicmp and strncasecmp, which
do roughly the same thing, namely compare two strings
case-insensitively up to a given bound. They have slightly different
implementations, but the only important difference is that strncasecmp
doesn't handle len==0 appropriately; it effectively becomes strcasecmp
in that case. strnicmp correctly says that two strings are always
equal in their first 0 characters.

strncasecmp is the POSIX name for this functionality. The first patch
renames the non-broken version to the standard name, and makes
strnicmp into a wrapper for strncasecmp. In order not to cause in-tree
users of strnicmp to pay the cost of the extra indirection, the second
patch replaces the declaration of strnicmp in string.h with a
macro. When and if all callers of strnicmp have been updated, that
hack can be removed.

Arch-specific versions of these functions could complicate matters,
but fortunately the only #define of either __HAVE macro is in a
!__KERNEL__ section in arch/frv/include/asm/string.h.

The other problem is how to deal with modules that may be using
strnicmp. The proper fix would probably involve some alias/linker
magic, but I have no idea how to do that (hence the RFC).

Rasmus Villemoes (2):
  lib: string: Remove duplicated function
  lib: string: Make all calls to strnicmp into calls to strncasecmp

 include/linux/string.h |  2 +-
 lib/string.c           | 28 +++++++++++-----------------
 2 files changed, 12 insertions(+), 18 deletions(-)

-- 
2.0.4

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