From: Christoph Hellwig <hch@infradead.org>
To: Mike Snitzer <snitzer@redhat.com>
Cc: Sergei Shtepa <sergei.shtepa@veeam.com>,
Christoph Hellwig <hch@infradead.org>,
Alasdair Kergon <agk@redhat.com>, Hannes Reinecke <hare@suse.de>,
Jens Axboe <axboe@kernel.dk>,
dm-devel@redhat.com, linux-block@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-api@vger.kernel.org,
pavel.tide@veeam.com
Subject: Re: [PATCH v7 1/3] block: add blk_mq_is_queue_frozen()
Date: Sun, 14 Mar 2021 09:14:41 +0000 [thread overview]
Message-ID: <20210314091441.GA3773360@infradead.org> (raw)
In-Reply-To: <20210312190641.GA2550@redhat.com>
On Fri, Mar 12, 2021 at 02:06:41PM -0500, Mike Snitzer wrote:
> This is returning a frozen state that is immediately stale. I don't
> think any code calling this is providing the guarantees you think it
> does due to the racey nature of this state once the mutex is dropped.
The code only uses it for asserts in the form of WARN_ONs.
WARNING: multiple messages have this Message-ID (diff)
From: Christoph Hellwig <hch@infradead.org>
To: Mike Snitzer <snitzer@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>,
linux-block@vger.kernel.org, linux-api@vger.kernel.org,
pavel.tide@veeam.com, linux-kernel@vger.kernel.org,
Christoph Hellwig <hch@infradead.org>,
dm-devel@redhat.com, Sergei Shtepa <sergei.shtepa@veeam.com>,
Alasdair Kergon <agk@redhat.com>
Subject: Re: [dm-devel] [PATCH v7 1/3] block: add blk_mq_is_queue_frozen()
Date: Sun, 14 Mar 2021 09:14:41 +0000 [thread overview]
Message-ID: <20210314091441.GA3773360@infradead.org> (raw)
In-Reply-To: <20210312190641.GA2550@redhat.com>
On Fri, Mar 12, 2021 at 02:06:41PM -0500, Mike Snitzer wrote:
> This is returning a frozen state that is immediately stale. I don't
> think any code calling this is providing the guarantees you think it
> does due to the racey nature of this state once the mutex is dropped.
The code only uses it for asserts in the form of WARN_ONs.
--
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dm-devel@redhat.com
https://listman.redhat.com/mailman/listinfo/dm-devel
next prev parent reply other threads:[~2021-03-14 9:16 UTC|newest]
Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-12 15:44 [PATCH v7 0/3] block device interposer Sergei Shtepa
2021-03-12 15:44 ` [dm-devel] " Sergei Shtepa
2021-03-12 15:44 ` [PATCH v7 1/3] block: add blk_mq_is_queue_frozen() Sergei Shtepa
2021-03-12 15:44 ` [dm-devel] " Sergei Shtepa
2021-03-12 19:06 ` Mike Snitzer
2021-03-12 19:06 ` [dm-devel] " Mike Snitzer
2021-03-14 9:14 ` Christoph Hellwig [this message]
2021-03-14 9:14 ` Christoph Hellwig
2021-03-15 12:06 ` Sergei Shtepa
2021-03-15 12:06 ` [dm-devel] " Sergei Shtepa
2021-03-12 15:44 ` [PATCH v7 2/3] block: add bdev_interposer Sergei Shtepa
2021-03-12 15:44 ` [dm-devel] " Sergei Shtepa
2021-03-14 9:28 ` Christoph Hellwig
2021-03-14 9:28 ` [dm-devel] " Christoph Hellwig
2021-03-15 13:06 ` Sergei Shtepa
2021-03-15 13:06 ` [dm-devel] " Sergei Shtepa
2021-03-16 8:09 ` Ming Lei
2021-03-16 8:09 ` [dm-devel] " Ming Lei
2021-03-16 16:35 ` Sergei Shtepa
2021-03-16 16:35 ` [dm-devel] " Sergei Shtepa
2021-03-17 3:03 ` Ming Lei
2021-03-17 3:03 ` [dm-devel] " Ming Lei
2021-03-17 12:22 ` Sergei Shtepa
2021-03-17 12:22 ` [dm-devel] " Sergei Shtepa
2021-03-17 15:04 ` Mike Snitzer
2021-03-17 15:04 ` [dm-devel] " Mike Snitzer
2021-03-17 18:14 ` Sergei Shtepa
2021-03-17 18:14 ` [dm-devel] " Sergei Shtepa
2021-03-17 19:13 ` Mike Snitzer
2021-03-17 19:13 ` [dm-devel] " Mike Snitzer
2021-03-18 14:56 ` Sergei Shtepa
2021-03-18 14:56 ` [dm-devel] " Sergei Shtepa
2021-03-17 14:58 ` Mike Snitzer
2021-03-17 14:58 ` [dm-devel] " Mike Snitzer
2021-03-12 15:44 ` [PATCH v7 3/3] dm: add DM_INTERPOSED_FLAG Sergei Shtepa
2021-03-12 15:44 ` [dm-devel] " Sergei Shtepa
2021-03-12 19:00 ` Mike Snitzer
2021-03-12 19:00 ` [dm-devel] " Mike Snitzer
2021-03-15 12:29 ` Sergei Shtepa
2021-03-15 12:29 ` [dm-devel] " Sergei Shtepa
2021-03-14 9:30 ` Christoph Hellwig
2021-03-14 9:30 ` [dm-devel] " Christoph Hellwig
2021-03-15 13:25 ` Sergei Shtepa
2021-03-15 13:25 ` [dm-devel] " Sergei Shtepa
2021-03-16 15:23 ` Christoph Hellwig
2021-03-16 15:23 ` [dm-devel] " Christoph Hellwig
2021-03-16 15:25 ` Christoph Hellwig
2021-03-16 15:25 ` [dm-devel] " Christoph Hellwig
2021-03-16 16:20 ` Sergei Shtepa
2021-03-16 16:20 ` [dm-devel] " Sergei Shtepa
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