Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751091AbbK0F3i (ORCPT ); Fri, 27 Nov 2015 00:29:38 -0500 Received: from TYO202.gate.nec.co.jp ([210.143.35.52]:49868 "EHLO tyo202.gate.nec.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750746AbbK0F3f convert rfc822-to-8bit (ORCPT ); Fri, 27 Nov 2015 00:29:35 -0500 From: Naoya Horiguchi To: Piotr Kwapulinski CC: "mhocko@suse.com" , "akpm@linux-foundation.org" , "oleg@redhat.com" , "cmetcalf@ezchip.com" , "mszeredi@suse.cz" , "viro@zeniv.linux.org.uk" , "dave@stgolabs.net" , "kirill.shutemov@linux.intel.com" , "aarcange@redhat.com" , "iamjoonsoo.kim@lge.com" , "jack@suse.cz" , "xiexiuqi@huawei.com" , "vbabka@suse.cz" , "Vineet.Gupta1@synopsys.com" , "riel@redhat.com" , "gang.chen.5i5j@gmail.com" , "linux-kernel@vger.kernel.org" , "linux-mm@kvack.org" Subject: Re: [PATCH v3] mm/mmap.c: remove incorrect MAP_FIXED flag comparison from mmap_region Thread-Topic: [PATCH v3] mm/mmap.c: remove incorrect MAP_FIXED flag comparison from mmap_region Thread-Index: AQHRJhWebDPTgOSkiEOBBQJMabyyu56uxZ0A Date: Fri, 27 Nov 2015 05:27:39 +0000 Message-ID: <20151127052738.GA25042@hori1.linux.bs1.fc.nec.co.jp> References: <20151123081946.GA21050@dhcp22.suse.cz> <1448300202-5004-1-git-send-email-kwapulinski.piotr@gmail.com> In-Reply-To: <1448300202-5004-1-git-send-email-kwapulinski.piotr@gmail.com> Accept-Language: ja-JP, en-US Content-Language: ja-JP X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.128.101.31] Content-Type: text/plain; charset="iso-2022-jp" Content-ID: Content-Transfer-Encoding: 8BIT MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1626 Lines: 46 On Mon, Nov 23, 2015 at 06:36:42PM +0100, Piotr Kwapulinski wrote: > The following flag comparison in mmap_region makes no sense: > > if (!(vm_flags & MAP_FIXED)) > return -ENOMEM; > > The condition is always false and thus the above "return -ENOMEM" is never > executed. The vm_flags must not be compared with MAP_FIXED flag. > The vm_flags may only be compared with VM_* flags. > MAP_FIXED has the same value as VM_MAYREAD. > Hitting the rlimit is a slow path and find_vma_intersection should realize > that there is no overlapping VMA for !MAP_FIXED case pretty quickly. > > Remove the code that makes no sense. > > Signed-off-by: Piotr Kwapulinski Looks good to me. Thank you. Reviewed-by: Naoya Horiguchi > --- > mm/mmap.c | 3 --- > 1 file changed, 3 deletions(-) > > diff --git a/mm/mmap.c b/mm/mmap.c > index 2ce04a6..42a8259 100644 > --- a/mm/mmap.c > +++ b/mm/mmap.c > @@ -1551,9 +1551,6 @@ unsigned long mmap_region(struct file *file, unsigned long addr, > * MAP_FIXED may remove pages of mappings that intersects with > * requested mapping. Account for the pages it would unmap. > */ > - if (!(vm_flags & MAP_FIXED)) > - return -ENOMEM; > - > nr_pages = count_vma_pages_range(mm, addr, addr + len); > > if (!may_expand_vm(mm, (len >> PAGE_SHIFT) - nr_pages)) > -- > 2.6.2 > -- 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/