From: Marek Szyprowski <m.szyprowski@samsung.com>
To: Ming Lei <ming.lei@redhat.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 16:16:32 +0200 [thread overview]
Message-ID: <2fcd389f-b341-7cd1-692b-8c9d1918198a@samsung.com> (raw)
In-Reply-To: <20200701134512.GA2443512@T590>
Hi Ming,
On 01.07.2020 15:45, Ming Lei wrote:
> On Wed, Jul 01, 2020 at 03:01:03PM +0200, Marek Szyprowski wrote:
>> 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)?
dwmmc-exynos (drivers/mmc/host/dw_mmc-exynos.c)
> 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.
Best regards
--
Marek Szyprowski, PhD
Samsung R&D Institute Poland
next prev parent reply other threads:[~2020-07-01 14:16 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
2020-07-01 14:16 ` Marek Szyprowski [this message]
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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