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From: Tejun Heo <tj@kernel.org>
To: Dmitry Monakhov <dmtrmonakhov@yandex-team.ru>
Cc: linux-kernel@vger.kernel.org, axboe@kernel.dk
Subject: Re: [PATCH] blk-throttle: fix race between submitter and throttler thread
Date: Thu, 20 May 2021 11:00:27 -0400	[thread overview]
Message-ID: <YKZ5i5P8fL8bgq7G@slm.duckdns.org> (raw)
In-Reply-To: <20210513082827.1818-1-dmtrmonakhov@yandex-team.ru>

Hello, Dmitry.

This generally looks good to me. A couple nits below.

> @@ -277,6 +277,8 @@ static struct bio *__bio_chain_endio(struct bio *bio)
>  {
>  	struct bio *parent = bio->bi_private;
>  
> +	BUG_ON(!bio_flagged(parent, BIO_CHAIN));

Let's do WARN_ON_ONCE().

> @@ -2270,6 +2285,8 @@ bool blk_throtl_bio(struct bio *bio)
>  
>  	td->nr_queued[rw]++;
>  	throtl_add_bio_tg(bio, qn, tg);

Can you add some comment here explaining how now that the bio is added for
throttling, there are two accessors of it and the bio must not be modified
without holding the lock?

Thank you.

-- 
tejun

  reply	other threads:[~2021-05-20 15:00 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-13  8:28 Dmitry Monakhov
2021-05-20 15:00 ` Tejun Heo [this message]
2021-05-20 17:00   ` Dmitry Monakhov
2021-05-20 17:07     ` Tejun Heo

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