From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755592AbaHZVhK (ORCPT ); Tue, 26 Aug 2014 17:37:10 -0400 Received: from mail-pd0-f176.google.com ([209.85.192.176]:38751 "EHLO mail-pd0-f176.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755286AbaHZVhI (ORCPT ); Tue, 26 Aug 2014 17:37:08 -0400 Message-ID: <53FCFE01.8080701@kernel.dk> Date: Tue, 26 Aug 2014 15:37:05 -0600 From: Jens Axboe User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.0 MIME-Version: 1.0 To: Jeff Moyer CC: Joe Lawrence , linux-kernel@vger.kernel.org, Jiri Kosina , Boaz Harrosh Subject: Re: [PATCH v3 0/2] block,scsi: fixup blk_get_request dead queue scenarios References: <1404329718-19367-1-git-send-email-joe.lawrence@stratus.com> <53FCF9DB.6010501@kernel.dk> <53FCFD40.2010903@kernel.dk> In-Reply-To: <53FCFD40.2010903@kernel.dk> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 08/26/2014 03:33 PM, Jens Axboe wrote: > On 08/26/2014 03:27 PM, Jeff Moyer wrote: >> Jens Axboe writes: >> >>> On 08/26/2014 11:24 AM, Jeff Moyer wrote: >>>> Joe Lawrence writes: >>>> >>>>> v2->v3: rebase to 3.16-rc2, consider return values from the >>>>> blk_mq_alloc_request leg of the blk_get_request callchain >>>>> (noted by Jeff), noted in the second patch changelog. >>>>> >>>>> blk_mq_queue_enter may return 0 or errno, which >>>>> blk_mq_alloc_request can propogate out via ERR_PTR. >>>>> __blk_mq_alloc_request doesn't include any blk_queue_dying >>>>> checks, so I'm assuming that its failures can be attributed >>>>> to -EWOULDBLOCK under !GFP_WAIT conditions. >>>>> >>>>> v1->v2: incorporate Jeff's feedback in bsg_map_hdr() and Reviewed-by >>>>> tags. >>>>> >>>>> Joe Lawrence (2): >>>>> block,scsi: verify return pointer from blk_get_request >>>>> block,scsi: fixup blk_get_request dead queue scenarios >>>> >>>> Jens, >>>> >>>> Did this patch set fall through the cracks again? >>> >>> Falling through the cracks implies that I meant to apply it and did not, >>> which was not the case. >> >> Sorry, I was mislead by our earlier conversation on this (mail inline >> below). > > I changed my mind, it didn't feel fully baked to me. > >>> But I think we're at the point now where I'm finally comfortable with >>> applying it. So, Joe, could you ensure that it applies to 3.17-rc2, >>> then I will roll it in to the updates for 3.18. >> >> Joe, you will have one hunk to modify for sure, in scsi_ioctl.c. A >> previous patch added a check for null, but ended up returning the wrong >> value (ENOMEM instead of ENODEV). > > I have applied the first one, will look over the second one and hand > apply it. Seems the NULL return was completely removed, so we _should_ > be ok on the IS_ERR() conversion, though that sort of thing always > worries me a little bit. A NULL return can quickly show up again, and > then they would all fail. Additionally, there's still quite a few places that call blk_get_request() and don't check the error return if __GFP_WAIT is set. Since most of the point of this is to fix segfaulting on queue dead scenarios, why aren't they all converted? -- Jens Axboe