From: Bart Van Assche <Bart.VanAssche@sandisk.com>
To: "hare@suse.de" <hare@suse.de>,
"martin.petersen@oracle.com" <martin.petersen@oracle.com>
Cc: "linux-scsi@vger.kernel.org" <linux-scsi@vger.kernel.org>,
"james.bottomley@hansenpartnership.com"
<james.bottomley@hansenpartnership.com>,
"hck@suse.de" <hck@suse.de>, "hare@suse.com" <hare@suse.com>
Subject: Re: [PATCH] sd: use async_probe cookie to avoid deadlocks
Date: Tue, 21 Mar 2017 13:02:45 +0000 [thread overview]
Message-ID: <1490101348.2602.3.camel@sandisk.com> (raw)
In-Reply-To: <1490098475-21884-1-git-send-email-hare@suse.de>
On Tue, 2017-03-21 at 13:14 +0100, Hannes Reinecke wrote:
> With the current design we're waiting for all async probes to
> finish when removing any sd device.
> This might lead to a livelock where the 'remove' call is blocking
> for any probe calls to finish, and the probe calls are waiting for
> a response, which will never be processes as the thread handling
> the responses is waiting for the remove call to finish.
> Which is completely pointless as we only _really_ care for the
> probe on _this_ device to be completed; any other probing can
> happily continue for all we care.
> So save the async probing cookie in the structure and only wait
> if this specific probe is still active.
Nice work! This may even help to reduce system boot time.
Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com>
next prev parent reply other threads:[~2017-03-21 13:03 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-21 12:14 [PATCH] sd: use async_probe cookie to avoid deadlocks Hannes Reinecke
2017-03-21 13:02 ` Bart Van Assche [this message]
2017-03-21 13:05 ` James Bottomley
2017-03-21 13:30 ` Bart Van Assche
2017-03-21 13:33 ` James Bottomley
2017-03-21 13:42 ` Bart Van Assche
2017-03-21 15:32 ` Hannes Reinecke
2017-03-21 15:25 ` Hannes Reinecke
2017-03-21 15:33 ` James Bottomley
2017-03-21 16:21 ` Hannes Reinecke
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