From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754151AbbIBWlJ (ORCPT ); Wed, 2 Sep 2015 18:41:09 -0400 Received: from mx0a-00082601.pphosted.com ([67.231.145.42]:53951 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753182AbbIBWlI (ORCPT ); Wed, 2 Sep 2015 18:41:08 -0400 Subject: Re: [GIT PULL] SG changes for 4.3 To: Linus Torvalds References: <20150902165833.GC14454@kernel.dk> CC: Linux Kernel Mailing List From: Jens Axboe Message-ID: <55E77B00.4040302@fb.com> Date: Wed, 2 Sep 2015 16:41:04 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.2.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 8bit X-Originating-IP: [192.168.54.13] X-Proofpoint-Spam-Reason: safe X-FB-Internal: Safe X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:5.14.151,1.0.33,0.0.0000 definitions=2015-09-02_08:2015-09-02,2015-09-02,1970-01-01 signatures=0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 09/02/2015 04:34 PM, Linus Torvalds wrote: > Jens, > > On Wed, Sep 2, 2015 at 9:58 AM, Jens Axboe wrote: >> >> This pull request contains a set of scatter-gather related changes/fixes >> for 4.3. It contains: > > This results in several new and annoying warnings. They may all be ok > code, but they are very distracting. Please stop introducing new > warnings to the build, because by now most of the warnings I see come > from the block layer. > > block/blk-merge.c: In function ‘blk_queue_split’: > include/linux/blkdev.h:1368:21: warning: ‘bvprv.bv_offset’ may be > used uninitialized in this function [-Wmaybe-uninitialized] > ((bprv->bv_offset + bprv->bv_len) & queue_virt_boundary(q)); > > (it gives this for bv_len too). The reason seems to be that disgusting > situation where "bvprv" is uninitiatlized unless "split" is true, and > the code looks like it is correct, but the compiler clearly has a hard > time seeing it. It took me a while too, so I can't really blame it. > > Either initialize bvprv to something explicit, or make the code clear > enough that the compiler can see that it is never used uninitialized. > Because those compiler warnings are sometimes real, and we can't just > ignore them. > > There was another type-based warning introduced by your core block > pull (size_t vs unsigned int). I think it's a repeat offender that got reintroduced. I'll fix it up. -- Jens Axboe