Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752758AbaFDPsK (ORCPT ); Wed, 4 Jun 2014 11:48:10 -0400 Received: from mail-pd0-f181.google.com ([209.85.192.181]:36135 "EHLO mail-pd0-f181.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751592AbaFDPsI (ORCPT ); Wed, 4 Jun 2014 11:48:08 -0400 Message-ID: <538F3FB5.2020102@kernel.dk> Date: Wed, 04 Jun 2014 09:48:05 -0600 From: Jens Axboe User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.5.0 MIME-Version: 1.0 To: Ming Lei , Christoph Hellwig CC: Shaohua Li , Linux Kernel Mailing List Subject: Re: [patch]blk-mq: blk_mq_tag_to_rq should handle flush request References: <20140509120733.GA27918@kernel.org> <20140509150018.GA26215@infradead.org> <20140510040023.GA13788@kernel.org> <5388912F.7010609@kernel.dk> <20140604111133.GA7826@infradead.org> <538F2A11.4060800@kernel.dk> <20140604142012.GA20056@infradead.org> <538F331F.60101@kernel.dk> <20140604145803.GA7826@infradead.org> <538F34FB.7050003@kernel.dk> <20140604153159.GA27096@infradead.org> In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 06/04/2014 09:43 AM, Ming Lei wrote: > On Wed, Jun 4, 2014 at 11:31 PM, Christoph Hellwig wrote: >> On Wed, Jun 04, 2014 at 09:02:19AM -0600, Jens Axboe wrote: >>>> scsi_mq_find_tag only gets the scsi host, which may have multiple >>>> queues. When called from scsi_find_tag we actually have a scsi device, >>>> so that's not an issue, but when called from scsi_host_find_tag the >>>> driver only provides the host. >>> >>> Only solution I see right now is to have the flush_rq in the shared >>> tags, but that would potentially be a regression for multiple >>> devices and heavy flush uses cases. I'll see if I can come up with >>> something better, or maybe Shaohua has an idea. >> >> What about something like the following (untest, uncompiled, maybe >> pseudo-code): >> >> struct request *blk_mq_tag_to_rq(struct blk_mq_tags *tags, unsigned int tag) >> { >> struct request *rq = tags->rqs[tag]; >> >> if ((rq->cmd_flags & REQ_FLUSH_SEQ) && rq->q->flush_rq->tag == tag) >> return rq->q->flush_rq; >> return rq; >> } > > Looks we thought it together, :-) > > Also maybe the flush_rq->tag need to be cleared in flush_end_io(). It clears the command flag, so that should be enough. -- Jens Axboe -- 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/