From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753099AbYIVIkg (ORCPT ); Mon, 22 Sep 2008 04:40:36 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751877AbYIVIk2 (ORCPT ); Mon, 22 Sep 2008 04:40:28 -0400 Received: from fgwmail5.fujitsu.co.jp ([192.51.44.35]:50008 "EHLO fgwmail5.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751922AbYIVIk2 (ORCPT ); Mon, 22 Sep 2008 04:40:28 -0400 From: KOSAKI Motohiro To: Andrew Morton Subject: Re: [PATCH] mm: do_generic_file_read() never gets a NULL 'filp' argument Cc: kosaki.motohiro@jp.fujitsu.com, Krishna Kumar , linux-kernel@vger.kernel.org In-Reply-To: <20080922013338.8e1c10ff.akpm@linux-foundation.org> References: <20080922061610.20158.86022.sendpatchset@localhost.localdomain> <20080922013338.8e1c10ff.akpm@linux-foundation.org> Message-Id: <20080922173703.C323.KOSAKI.MOTOHIRO@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Mailer: Becky! ver. 2.42 [ja] Date: Mon, 22 Sep 2008 17:40:24 +0900 (JST) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > On Mon, 22 Sep 2008 11:46:10 +0530 Krishna Kumar wrote: > > > From: Krishna Kumar > > > > The 'filp' argument to do_generic_file_read() is never NULL. > > > > How did you verify this? > > NFS used to like passing NULL file*'s into VFS functions. I don't > recall whether it affected do_generic_file_read(). Andrew, current do_generic_file_read have filp dereference at the beginning of function. So, I believe nobody pass to NULL. static void do_generic_file_read(struct file *filp, loff_t *ppos, read_descriptor_t *desc, read_actor_t actor) { struct address_space *mapping = filp->f_mapping; /* here */ struct inode *inode = mapping->host; struct file_ra_state *ra = &filp->f_ra; /* ditto */ pgoff_t index; pgoff_t last_index; pgoff_t prev_index; > > > mm/filemap.c | 3 +-- > > 1 file changed, 1 insertion(+), 2 deletions(-) > > > > diff -ruNp 2.6.27-rc7-org/mm/filemap.c 2.6.27-rc7-new/mm/filemap.c > > --- 2.6.27-rc7-org/mm/filemap.c 2008-09-17 12:53:25.000000000 +0530 > > +++ 2.6.27-rc7-new/mm/filemap.c 2008-09-17 12:53:59.000000000 +0530 > > @@ -1186,8 +1186,7 @@ out: > > ra->prev_pos |= prev_offset; > > > > *ppos = ((loff_t)index << PAGE_CACHE_SHIFT) + offset; > > - if (filp) > > - file_accessed(filp); > > + file_accessed(filp); > > } > > > > int file_read_actor(read_descriptor_t *desc, struct page *page, > -- > 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/