Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751727AbWCEGRZ (ORCPT ); Sun, 5 Mar 2006 01:17:25 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751894AbWCEGRZ (ORCPT ); Sun, 5 Mar 2006 01:17:25 -0500 Received: from smtp.osdl.org ([65.172.181.4]:51118 "EHLO smtp.osdl.org") by vger.kernel.org with ESMTP id S1751727AbWCEGRZ (ORCPT ); Sun, 5 Mar 2006 01:17:25 -0500 Date: Sat, 4 Mar 2006 22:15:50 -0800 From: Andrew Morton To: "Jan Beulich" Cc: linux-kernel@vger.kernel.org Subject: Re: [PATCH] adjust /dev/{kmem,mem,port} write handlers Message-Id: <20060304221550.6892c7ba.akpm@osdl.org> In-Reply-To: <44081B03.76F0.0078.0@novell.com> References: <44081B03.76F0.0078.0@novell.com> X-Mailer: Sylpheed version 1.0.4 (GTK+ 1.2.10; i386-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1834 Lines: 55 "Jan Beulich" wrote: > > The /dev/mem and /dev/kmem write handlers weren't fully POSIX compliant in > that they wouldn't always force the file pointer to be updated when returning > success status. > The /dev/port write handler was inconsistent with the /dev/mem and /dev/kmem > handlers in that when encountering a -EFAULT condition after already having > written a number of items it would return -EFAULT rather than the number of > bytes written. > > ... > > @@ -514,11 +510,10 @@ static ssize_t write_kmem(struct file * > if (len) { > written = copy_from_user(kbuf, buf, len); > if (written) { > - ssize_t ret; > - > + if (wrote + virtr) > + break; > free_page((unsigned long)kbuf); > - ret = wrote + virtr + (len - written); > - return ret ? ret : -EFAULT; > + return -EFAULT; > } > } > len = vwrite(kbuf, (char *)p, len); I think write_kmem() still isn't quie right - it needs to update `p' (and hence *ppos) to account for a partial copy_from_user(). (Please double-check) --- devel/drivers/char/mem.c~adjust-dev-kmemmemport-write-handlers-fix 2006-03-04 22:10:55.000000000 -0800 +++ devel-akpm/drivers/char/mem.c 2006-03-04 22:15:19.000000000 -0800 @@ -504,8 +504,11 @@ static ssize_t write_kmem(struct file * if (len) { written = copy_from_user(kbuf, buf, len); if (written) { - if (wrote + virtr) + if (wrote + virtr) { + p += len - written; + virtr += len - written; break; + } free_page((unsigned long)kbuf); return -EFAULT; } _ - 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/