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From: Ming Lei <ming.lei@redhat.com>
To: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Jens Axboe <axboe@kernel.dk>,
	linux-block@vger.kernel.org, Christoph Hellwig <hch@lst.de>,
	Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Subject: Re: [PATCH] blk-mq: put driver tag when this request is completed
Date: Wed, 1 Jul 2020 21:45:12 +0800	[thread overview]
Message-ID: <20200701134512.GA2443512@T590> (raw)
In-Reply-To: <57fb09b1-54ba-f3aa-f82c-d709b0e6b281@samsung.com>

Hi Marek,

On Wed, Jul 01, 2020 at 03:01:03PM +0200, Marek Szyprowski wrote:
> Hi
> 
> On 29.06.2020 11:47, Ming Lei wrote:
> > It is natural to release driver tag when this request is completed by
> > LLD or device since its purpose is for LLD use.
> >
> > One big benefit is that the released tag can be re-used quicker since
> > bio_endio() may take too long.
> >
> > Meantime we don't need to release driver tag for flush request.
> >
> > Cc: Christoph Hellwig <hch@lst.de>
> > Signed-off-by: Ming Lei <ming.lei@redhat.com>
> 
> This patch landed recently in linux-next as commit 36a3df5a4574. Sadly 
> it causes a regression on one of my test systems (ARM 32bit, Samsung 
> Exynos5422 SoC based Odroid XU3 board with eMMC). The system boots fine 
> and then after a few seconds every executed command hangs. No 
> panic/ops/any other message. I will try to provide more information asap 
> I find something to share. Simple reverting it in linux-next is not 
> possible due to dependencies.

What is the exact eMMC's driver code(include the host driver)?

The usual way for handling completion is that host driver notifies block
layer via blk_mq_complete_request() after the LLD specific handling for
this request is done.

However, there might be driver which may use rq->tag in its rq completion
handler. I will see if the special case can be dealt with once you share
the driver info.


Thanks,
Ming


  reply	other threads:[~2020-07-01 13:45 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-29  9:47 [PATCH] blk-mq: put driver tag when this request is completed Ming Lei
2020-06-29 15:04 ` Christoph Hellwig
2020-06-29 15:56 ` Jens Axboe
     [not found] ` <CGME20200701130104eucas1p1f8dcce58bf704b726aee1e89980fe19e@eucas1p1.samsung.com>
2020-07-01 13:01   ` Marek Szyprowski
2020-07-01 13:45     ` Ming Lei [this message]
2020-07-01 14:16       ` Marek Szyprowski
2020-07-01 14:58         ` Marek Szyprowski
2020-07-02  1:22         ` Ming Lei
2020-07-02  5:03           ` Jens Axboe
2020-07-02  8:04           ` Marek Szyprowski
2020-07-02  9:23             ` Ming Lei
2020-07-02 10:19               ` Marek Szyprowski
2020-07-02 11:48                 ` Ming Lei
2020-07-02 12:12                   ` Marek Szyprowski
2020-07-06 14:40 Ming Lei

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