From: Jens Axboe <axboe@kernel.dk>
To: Phillip Potter <phil@philpotter.co.uk>
Cc: linux-block@vger.kernel.org
Subject: Re: [PATCH v3] drivers/cdrom: improved ioctl for media change detection
Date: Tue, 14 Sep 2021 20:05:41 -0600 [thread overview]
Message-ID: <5766487b-a5b4-9590-3f56-2c1d23819ffa@kernel.dk> (raw)
In-Reply-To: <20210913230942.1188-1-phil@philpotter.co.uk>
On 9/13/21 5:09 PM, Phillip Potter wrote:
> From: Lukas Prediger <lumip@lumip.de>
>
> The current implementation of the CDROM_MEDIA_CHANGED ioctl relies on
> global state, meaning that only one process can detect a disc change
> while the ioctl call will return 0 for other calling processes afterwards
> (see bug 213267).
>
> This introduces a new cdrom ioctl, CDROM_TIMED_MEDIA_CHANGE, that
> works by maintaining a timestamp of the last detected disc change instead
> of a boolean flag: Processes calling this ioctl command can provide
> a timestamp of the last disc change known to them and receive
> an indication whether the disc was changed since then and the updated
> timestamp.
>
> I considered fixing the buggy behavior in the original
> CDROM_MEDIA_CHANGED ioctl but that would require maintaining state
> for each calling process in the kernel, which seems like a worse
> solution than introducing this new ioctl.
Applied for 5.16, thanks.
--
Jens Axboe
next prev parent reply other threads:[~2021-09-15 2:05 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-13 23:09 [PATCH v3] drivers/cdrom: improved ioctl for media change detection Phillip Potter
2021-09-15 2:05 ` Jens Axboe [this message]
2021-09-16 23:07 ` Phillip Potter
-- strict thread matches above, loose matches on Subject: below --
2021-09-10 21:16 Lukas Prediger
2021-09-10 21:41 ` Randy Dunlap
2021-09-11 11:00 ` Phillip Potter
2021-09-11 17:48 ` Lukas Prediger
2021-09-12 18:04 ` Phillip Potter
2021-09-12 19:12 ` Lukas Prediger
2021-09-13 7:50 ` Phillip Potter
2021-10-06 20:52 ` Randy Dunlap
2021-10-07 23:04 ` Phillip Potter
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