Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754452AbYLSFzn (ORCPT ); Fri, 19 Dec 2008 00:55:43 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752323AbYLSFzf (ORCPT ); Fri, 19 Dec 2008 00:55:35 -0500 Received: from ocean.emcraft.com ([213.221.7.182]:33787 "EHLO ocean.emcraft.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752231AbYLSFze (ORCPT ); Fri, 19 Dec 2008 00:55:34 -0500 From: Yuri Tikhonov To: linux-kernel@vger.kernel.org Subject: [PATCH] mm/shmem.c: fix division by zero Date: Fri, 19 Dec 2008 08:44:57 +0300 User-Agent: KMail/1.9.4 Cc: linuxppc-dev@ozlabs.org, hugh@veritas.com, akpm@linux-foundation.org, paulus@samba.org, wd@denx.de, dzu@denx.de, yanok@emcraft.com, miltonm@bga.com, viro@zeniv.linux.org.uk, Geert.Uytterhoeven@sonycom.com MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200812190844.57996.yur@emcraft.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2407 Lines: 61 The following patch fixes division by zero, which we have in shmem_truncate_range() and shmem_unuse_inode(), if use big PAGE_SIZE values (e.g. 256KB on ppc44x). With 256KB PAGE_SIZE the ENTRIES_PER_PAGEPAGE constant becomes too large (0x1.0000.0000), so this patch just changes the types from 'ulong' to 'ullong' where it's necessary. Signed-off-by: Yuri Tikhonov --- mm/shmem.c | 8 ++++---- 1 files changed, 4 insertions(+), 4 deletions(-) diff --git a/mm/shmem.c b/mm/shmem.c index 0ed0752..99d7c91 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -57,7 +57,7 @@ #include #define ENTRIES_PER_PAGE (PAGE_CACHE_SIZE/sizeof(unsigned long)) -#define ENTRIES_PER_PAGEPAGE (ENTRIES_PER_PAGE*ENTRIES_PER_PAGE) +#define ENTRIES_PER_PAGEPAGE ((unsigned long long)ENTRIES_PER_PAGE*ENTRIES_PER_PAGE) #define BLOCKS_PER_PAGE (PAGE_CACHE_SIZE/512) #define SHMEM_MAX_INDEX (SHMEM_NR_DIRECT + (ENTRIES_PER_PAGEPAGE/2) * (ENTRIES_PER_PAGE+1)) @@ -95,7 +95,7 @@ static unsigned long shmem_default_max_inodes(void) } #endif -static int shmem_getpage(struct inode *inode, unsigned long idx, +static int shmem_getpage(struct inode *inode, unsigned long long idx, struct page **pagep, enum sgp_type sgp, int *type); static inline struct page *shmem_dir_alloc(gfp_t gfp_mask) @@ -533,7 +533,7 @@ static void shmem_truncate_range(struct inode *inode, loff_t start, loff_t end) int punch_hole; spinlock_t *needs_lock; spinlock_t *punch_lock; - unsigned long upper_limit; + unsigned long long upper_limit; inode->i_ctime = inode->i_mtime = CURRENT_TIME; idx = (start + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; @@ -1175,7 +1175,7 @@ static inline struct mempolicy *shmem_get_sbmpol(struct shmem_sb_info *sbinfo) * vm. If we swap it in we mark it dirty since we also free the swap * entry since a page cannot live in both the swap and page cache */ -static int shmem_getpage(struct inode *inode, unsigned long idx, +static int shmem_getpage(struct inode *inode, unsigned long long idx, struct page **pagep, enum sgp_type sgp, int *type) { struct address_space *mapping = inode->i_mapping; -- 1.6.0.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/