From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754962AbbCaP6D (ORCPT ); Tue, 31 Mar 2015 11:58:03 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:49619 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753513AbbCaP6A (ORCPT ); Tue, 31 Mar 2015 11:58:00 -0400 Date: Tue, 31 Mar 2015 17:57:56 +0200 From: "gregkh@linuxfoundation.org" To: Julia Lawall Cc: "Dhere, Chaitanya (C.)" , "oleg.drokin@intel.com" , "andreas.dilger@intel.com" , "viro@zeniv.linux.org.uk" , "jinshan.xiong@intel.com" , "aybuke.147@gmail.com" , "john.hammond@intel.com" , "HPDD-discuss@lists.01.org" , "devel@driverdev.osuosl.org" , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH] staging: lustre: replace kzalloc with copy_from_user with memdup_user Message-ID: <20150331155756.GA12842@kroah.com> References: <20150331150933.GA2833@chaitanya-Ideapad-Z560> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Mar 31, 2015 at 05:15:23PM +0200, Julia Lawall wrote: > On Tue, 31 Mar 2015, Dhere, Chaitanya (C.) wrote: > > > This patch replaces kzalloc and copy_from_user with memdup_user call > > This change was detected with coccinelle tool > > > > Signed-off-by: Chaitanya Dhere > > --- > > drivers/staging/lustre/lustre/llite/file.c | 11 +++-------- > > 1 file changed, 3 insertions(+), 8 deletions(-) > > > > diff --git a/drivers/staging/lustre/lustre/llite/file.c b/drivers/staging/lustre/lustre/llite/file.c > > index 85e74d1..85b5567 100644 > > --- a/drivers/staging/lustre/lustre/llite/file.c > > +++ b/drivers/staging/lustre/lustre/llite/file.c > > @@ -2368,14 +2368,9 @@ ll_file_ioctl(struct file *file, unsigned int cmd, unsigned long arg) > > struct hsm_state_set *hss; > > int rc; > > > > - hss = kzalloc(sizeof(*hss), GFP_NOFS); > > - if (!hss) > > - return -ENOMEM; > > - > > - if (copy_from_user(hss, (char *)arg, sizeof(*hss))) { > > - OBD_FREE_PTR(hss); > > - return -EFAULT; > > - } > > + hss = memdup_user((char *)arg, sizeof(*hss)); > > memdup_user will use the flag GFP_KERNEL, ie (__GFP_WAIT | __GFP_IO | > __GFP_FS), rather than the flag GFP_NOFS, ie (__GFP_WAIT | __GFP_IO), that > is specified. I don't know if this is a problem here. Yes, this is a filesystem, so this can't be changed, as we can't have the allocation go out and ask for more filesystem accesses in the middle of trying to do a filesystem access :) thanks, greg k-h