From: Christoph Hellwig <hch@infradead.org>
To: James Bottomley <jejb@linux.ibm.com>
Cc: Christoph Hellwig <hch@infradead.org>,
Merlijn Wajer <merlijn@archive.org>,
merlijn@wizzup.org, linux-scsi@vger.kernel.org,
Jens Axboe <axboe@kernel.dk>,
"Martin K. Petersen" <martin.petersen@oracle.com>,
Arnd Bergmann <arnd@arndb.de>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2] scsi: sr: get rid of sr global mutex
Date: Tue, 18 Feb 2020 09:23:47 -0800 [thread overview]
Message-ID: <20200218172347.GA3020@infradead.org> (raw)
In-Reply-To: <1582046428.16681.7.camel@linux.ibm.com>
On Tue, Feb 18, 2020 at 09:20:28AM -0800, James Bottomley wrote:
> > > Replace the global mutex with per-sr-device mutex.
> >
> > Do we actually need the lock at all? What is protected by it?
>
> We do at least for cdrom_open. It modifies the cdi structure with no
> other protection and concurrent modification would at least screw up
> the use counter which is not atomic. Same reasoning for cdrom_release.
Wouldn't the right fix to add locking to cdrom_open/release instead of
having an undocumented requirement for the callers?
next prev parent reply other threads:[~2020-02-18 17:23 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-18 14:39 [PATCH v2] scsi: sr: get rid of sr global mutex Merlijn Wajer
2020-02-18 17:12 ` Christoph Hellwig
2020-02-18 17:20 ` James Bottomley
2020-02-18 17:23 ` Christoph Hellwig [this message]
2020-02-18 17:28 ` James Bottomley
2020-02-18 17:31 ` Christoph Hellwig
2020-02-18 19:21 ` Merlijn B.W. Wajer
2020-02-18 19:46 ` Arnd Bergmann
2020-02-24 21:20 ` Merlijn B.W. Wajer
[not found] <9d50ecd4-9fd1-6865-5509-a5ef119828df () archive ! org>
2020-03-06 22:43 ` Simon Arlott
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