linux-kernel - Re: [PATCH 1/2] block: export __blk_complete

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <3970fdc7-52d9-d05b-4118-059d48bf4f2d@oracle.com>
Date:   Fri, 15 Jun 2018 11:04:02 +0800
From:   "jianchao.wang" <jianchao.w.wang@...cle.com>
To:     Ming Lei <tom.leiming@...il.com>
Cc:     Jens Axboe <axboe@...nel.dk>, Christoph Hellwig <hch@....de>,
        James Bottomley <jejb@...ux.vnet.ibm.com>,
        "Martin K. Petersen" <martin.petersen@...cle.com>,
        linux-block <linux-block@...r.kernel.org>,
        Linux SCSI List <linux-scsi@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 1/2] block: export __blk_complete_request

Hi Ming

Thanks for your kindly response.

On 06/15/2018 10:56 AM, Ming Lei wrote:
>>> IMO, ref-counter is just to fix the blk-mq req life recycle issue.
>>> It cannot replace the blk_mark_rq_complete which could avoid the race between
>>> timeout and io completion path.
>> The .timeout return BLK_EH_DONE doesn't always mean the request has been completed.
>> Such as scsi-mid layer, its .timeout callback return BLK_EH_DONE but the timed out
>> request is still in abort or eh process. What if a completion irq come during that ?
> For blk-mq, it is avoided by the atomic state change in
> __blk_mq_complete_request(),
> that is why I mentioned the question in my last reply.
> 

but blk_mq_check_expired doesn't do that.
do I miss anything ?

> But what if the timed-out request has been freed by EH? Then seems
> req's ref_counter

Thanks
Jianchao