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Subject: Re: INFO: task hung in blk_queue_enter
From:   Jens Axboe <axboe@kernel.dk>
In-Reply-To: <20180602045353.GA20257@ming.t460p>
Date:   Sat, 2 Jun 2018 07:48:26 -0600
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To:     Ming Lei <ming.lei@redhat.com>
Sender: linux-kernel-owner@vger.kernel.org
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> On Jun 1, 2018, at 10:54 PM, Ming Lei <ming.lei@redhat.com> wrote:
>=20
>> On Fri, Jun 01, 2018 at 10:31:13PM -0600, Jens Axboe wrote:
>> On 6/1/18 8:36 PM, Ming Lei wrote:
>>>> clear the bit when we need to, potentially even adding a debug check to=

>>>> blk_queue_enter_live() that complains if the ref was not already
>>>> elevated. Though that would be expensive, compared to the percpu inc
>>>> now. Not saying the bit is necessarily the best way forward, but I do
>>>> like it a LOT more than adding an argument to generic_make_request.
>>>=20
>>> We may introduce generic_make_request_with_ref() for blk_queue_split(),
>>> what do you think of the following patch?
>>=20
>> Functionally it'll work as well.
>=20
> If you are fine with this one, I'm glad to prepare for a normal one,
> so that we can save one precious bio flag, and the total number is
> just 13.

We=E2=80=99ve never had much issue with bio specific flags, I prefer that ap=
proach to a wrapper around generic_make_request().=20