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Subject: Re: [PATCH v3] libata: Use per port sync for detach
To:     Kai-Heng Feng <kai.heng.feng@canonical.com>
Cc:     John Garry <john.garry@huawei.com>,
        "open list:LIBATA SUBSYSTEM (Serial and Parallel ATA drivers)" 
        <linux-ide@vger.kernel.org>,
        open list <linux-kernel@vger.kernel.org>
References: <20200603074819.21639-1-kai.heng.feng@canonical.com>
From:   Jens Axboe <axboe@kernel.dk>
Message-ID: <88430982-e948-be34-b47b-2411b31eb187@kernel.dk>
Date:   Thu, 18 Jun 2020 09:21:57 -0600
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On 6/3/20 1:48 AM, Kai-Heng Feng wrote:
> Commit 130f4caf145c ("libata: Ensure ata_port probe has completed before
> detach") may cause system freeze during suspend.
> 
> Using async_synchronize_full() in PM callbacks is wrong, since async
> callbacks that are already scheduled may wait for not-yet-scheduled
> callbacks, causes a circular dependency.
> 
> Instead of using big hammer like async_synchronize_full(), use async
> cookie to make sure port probe are synced, without affecting other
> scheduled PM callbacks.

Queued up for 5.8, thanks.

-- 
Jens Axboe