Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755142Ab3DYG4s (ORCPT ); Thu, 25 Apr 2013 02:56:48 -0400 Received: from cn.fujitsu.com ([222.73.24.84]:53023 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1750991Ab3DYG4r (ORCPT ); Thu, 25 Apr 2013 02:56:47 -0400 X-IronPort-AV: E=Sophos;i="4.87,548,1363104000"; d="scan'208";a="7136079" Message-ID: <5178D330.9030505@cn.fujitsu.com> Date: Thu, 25 Apr 2013 14:54:40 +0800 From: Gu Zheng User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:7.0.1) Gecko/20110930 Thunderbird/7.0.1 MIME-Version: 1.0 To: Jan Kara CC: akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel , Al Viro , Jens Subject: Re: [PATCH] mm/filemap.c: fix criteria of calling iov_shorten() in generic_file_direct_write() References: <51764857.5010808@cn.fujitsu.com> <20130424122100.GA21962@quack.suse.cz> In-Reply-To: <20130424122100.GA21962@quack.suse.cz> X-MIMETrack: Itemize by SMTP Server on mailserver/fnst(Release 8.5.3|September 15, 2011) at 2013/04/25 14:54:50, Serialize by Router on mailserver/fnst(Release 8.5.3|September 15, 2011) at 2013/04/25 14:54:55, Serialize complete at 2013/04/25 14:54:55 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2187 Lines: 61 On 04/24/2013 08:21 PM, Jan Kara wrote: > On Tue 23-04-13 16:37:43, Gu Zheng wrote: >> From 35947e6535d92c54cf523470cc8811e8b5fee3e5 Mon Sep 17 00:00:00 2001 >> From: Gu Zheng >> Date: Tue, 23 Apr 2013 16:09:04 +0800 >> Subject: [PATCH] mm/filemap.c: fix criteria of calling iov_shorten() in generic_file_direct_write() >> >> generic_file_direct_write() compares 'count'(the max count we actually can write) >> with 'ocount'(the count we request to write) to see if there is need to call >> iov_shorten() to reduce number of segments and the iovec's length. If the >> 'count' is equal or greater than 'ocount', there is no need to call iov_shorten() >> indeed. So the judgement should be changed: >> 'if (count != ocount)' --> 'if (count < ocount)' > Thanks for the patch but it shouldn't be really possible that count > > ocount, should it? So your patch doesn't really fix anything. Or am I > missing something? Hi Jan, You are right, 'count' should not be greater than 'ocount' actually. Please ignore this patch. Thanks, Gu > > Honza >> >> Signed-off-by: Gu Zheng >> --- >> mm/filemap.c | 2 +- >> 1 files changed, 1 insertions(+), 1 deletions(-) >> >> diff --git a/mm/filemap.c b/mm/filemap.c >> index e1979fd..c566b9c 100644 >> --- a/mm/filemap.c >> +++ b/mm/filemap.c >> @@ -2183,7 +2183,7 @@ generic_file_direct_write(struct kiocb *iocb, const struct iovec *iov, >> size_t write_len; >> pgoff_t end; >> >> - if (count != ocount) >> + if (count < ocount) >> *nr_segs = iov_shorten((struct iovec *)iov, *nr_segs, count); >> >> write_len = iov_length(iov, *nr_segs); >> -- >> 1.7.7 >> >> -- >> 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/ -- 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/