From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759430AbYFXI1K (ORCPT ); Tue, 24 Jun 2008 04:27:10 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757335AbYFXI0w (ORCPT ); Tue, 24 Jun 2008 04:26:52 -0400 Received: from mgw1.diku.dk ([130.225.96.91]:45782 "EHLO mgw1.diku.dk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752491AbYFXI0u (ORCPT ); Tue, 24 Jun 2008 04:26:50 -0400 Date: Tue, 24 Jun 2008 10:26:47 +0200 (CEST) From: Julia Lawall To: akinobu.mita@gmail.com, linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org Subject: [PATCH 13/14] lib: 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. lib/swiotlb.c | 4 ---- 1 file changed, 4 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/lib/swiotlb.c b/lib/swiotlb.c --- a/lib/swiotlb.c +++ b/lib/swiotlb.c @@ -146,8 +146,6 @@ swiotlb_init_with_default_size(size_t de * Get IO TLB memory from the low pages */ io_tlb_start = alloc_bootmem_low_pages(bytes); - if (!io_tlb_start) - panic("Cannot allocate SWIOTLB buffer"); io_tlb_end = io_tlb_start + bytes; /* @@ -165,8 +163,6 @@ swiotlb_init_with_default_size(size_t de * Get the overflow emergency buffer */ io_tlb_overflow_buffer = alloc_bootmem_low(io_tlb_overflow); - if (!io_tlb_overflow_buffer) - panic("Cannot allocate SWIOTLB overflow buffer!\n"); printk(KERN_INFO "Placing software IO TLB between 0x%lx - 0x%lx\n", virt_to_bus(io_tlb_start), virt_to_bus(io_tlb_end));