From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx204.postini.com [74.125.245.204]) by kanga.kvack.org (Postfix) with SMTP id C52AF6B005C for ; Sat, 3 Aug 2013 22:14:35 -0400 (EDT) From: "Kirill A. Shutemov" Subject: [PATCH 15/23] mm, fs: avoid page allocation beyond i_size on read Date: Sun, 4 Aug 2013 05:17:17 +0300 Message-Id: <1375582645-29274-16-git-send-email-kirill.shutemov@linux.intel.com> In-Reply-To: <1375582645-29274-1-git-send-email-kirill.shutemov@linux.intel.com> References: <1375582645-29274-1-git-send-email-kirill.shutemov@linux.intel.com> Sender: owner-linux-mm@kvack.org List-ID: To: Andrea Arcangeli , Andrew Morton Cc: Al Viro , Hugh Dickins , Wu Fengguang , Jan Kara , Mel Gorman , linux-mm@kvack.org, Andi Kleen , Matthew Wilcox , "Kirill A. Shutemov" , Hillf Danton , Dave Hansen , Ning Qu , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, "Kirill A. Shutemov" , NeilBrown From: "Kirill A. Shutemov" I've noticed that we allocated unneeded page for cache on read beyond i_size. Simple test case (I checked it on ramfs): $ touch testfile $ cat testfile It triggers 'no_cached_page' code path in do_generic_file_read(). Looks like it's regression since commit a32ea1e. Let's fix it. Signed-off-by: Kirill A. Shutemov Cc: NeilBrown --- mm/filemap.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/mm/filemap.c b/mm/filemap.c index 066bbff..c31d296 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -1163,6 +1163,10 @@ static void do_generic_file_read(struct file *filp, loff_t *ppos, loff_t isize; unsigned long nr, ret; + isize = i_size_read(inode); + if (!isize || index > (isize - 1) >> PAGE_CACHE_SHIFT) + goto out; + cond_resched(); find_page: page = find_get_page(mapping, index); -- 1.8.3.2 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org