From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759464AbYFXI1k (ORCPT ); Tue, 24 Jun 2008 04:27:40 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1758265AbYFXI1P (ORCPT ); Tue, 24 Jun 2008 04:27:15 -0400 Received: from mgw1.diku.dk ([130.225.96.91]:45791 "EHLO mgw1.diku.dk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757076AbYFXI1M (ORCPT ); Tue, 24 Jun 2008 04:27:12 -0400 Date: Tue, 24 Jun 2008 10:27:10 +0200 (CEST) From: Julia Lawall To: akinobu.mita@gmail.com, linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org Subject: [PATCH 14/14] mm: Eliminate NULL test and memset after alloc_bootmem Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Julia Lawall As noted by Akinobu Mita in patch b1fceac2b9e04d278316b2faddf276015fc06e3b, alloc_bootmem and related functions never return NULL and always return a zeroed region of memory. Thus a NULL test or memset after calls to these functions is unnecessary. mm/sparse.c | 2 -- 1 file changed, 2 deletions(-) This was fixed using the following semantic patch. (http://www.emn.fr/x-info/coccinelle/) // @@ expression E; statement S; @@ E = \(alloc_bootmem\|alloc_bootmem_low\|alloc_bootmem_pages\|alloc_bootmem_low_pages\)(...) ... when != E ( - BUG_ON (E == NULL); | - if (E == NULL) S ) @@ expression E,E1; @@ E = \(alloc_bootmem\|alloc_bootmem_low\|alloc_bootmem_pages\|alloc_bootmem_low_pages\)(...) ... when != E - memset(E,0,E1); // Signed-off-by: Julia Lawall --- diff -u -p a/mm/sparse.c b/mm/sparse.c --- a/mm/sparse.c +++ b/mm/sparse.c @@ -324,8 +324,6 @@ void __init sparse_init(void) */ size = sizeof(unsigned long *) * NR_MEM_SECTIONS; usemap_map = alloc_bootmem(size); - if (!usemap_map) - panic("can not allocate usemap_map\n"); for (pnum = 0; pnum < NR_MEM_SECTIONS; pnum++) { if (!present_section_nr(pnum))