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From: Arnd Bergmann <arnd@arndb•de>
To: codalist@coda•cs.cmu.edu,
	ksummit-2010-discuss@lists•linux-foundation.org
Cc: autofs@linux•kernel.org, linux-media@vger•kernel.org,
	dri-devel@lists•freedesktop.org,
	Christoph Hellwig <hch@infradead•org>,
	Mikulas Patocka <mikulas@artax•karlin.mff.cuni.cz>,
	Trond Myklebust <Trond.Myklebust@netapp•com>,
	Petr Vandrovec <vandrove@vc•cvut.cz>,
	Anders Larsen <al@alarsen•net>, Jan Kara <jack@suse•cz>,
	Evgeniy Dushistov <dushistov@mail•ru>,
	Ingo Molnar <mingo@elte•hu>,
	netdev@vger•kernel.org, Samuel Ortiz <samuel@sortiz•org>,
	Arnaldo Carvalho de Melo <acme@ghostprotocols•net>,
	linux-kernel@vger•kernel.org, linux-fsdevel@vger•kernel.org,
	Andrew Hendry <andrew.hendry@gmail•com>,
	David Miller <davem@davemloft•net>,
	Jan Harkes <jaharkes@cs•cmu.edu>,
	Bryan Schumaker <bjschuma@netapp•com>
Subject: [v2] Remaining BKL users, what to do
Date: Mon, 18 Oct 2010 17:42:06 +0200	[thread overview]
Message-ID: <201010181742.06678.arnd@arndb.de> (raw)
In-Reply-To: <201009161632.59210.arnd@arndb.de>

This is a update on the current progress for the BKL removal, reflecting
what is currently in linux-next.

Maybe we can briefly discuss this at the kernel summit to decide if we
want a quick death of the BKL, i.e. fixing/disabling/staging-out the
remaining users in 2.6.38 or rather leave them there indefinitely.

On Thursday 16 September 2010, Arnd Bergmann wrote:
> The big kernel lock is gone from almost all code in linux-next, this is
> the status of what I think will happen to the remaining users:
> 
> drivers/gpu/drm/i810/{i810,i830}_dma.c:
> 	Fixable, but needs someone with the hardware to test. Can probably be
> 	marked CONFIG_BROKEN_ON_SMP if nobody cares.

Still open, no good solution for this.

> drivers/media/video (V4L):
> 	Mauro is working on it, some drivers get moved to staging while the
> 	others get fixed. An easy workaround would be possible by adding
> 	per-driver mutexes, but Mauro wants to it properly by locking all
> 	the right places.

Progressing well, patches are being worked on.

> fs/adfs:
> 	Probably not hard to fix, but needs someone to test it.
> 	adfs has only seen janitorial fixes for the last 5 years.
> 	Do we know of any users?

Nobody replied.

> fs/autofs:
> 	Pretty much dead, replaced by autofs4. I'd suggest moving this
> 	to drivers/staging in 2.6.37 and letting it die there.

Now in staging.

> fs/coda:
> 	Coda seems to have an active community, but not all of their
> 	code is actually part of linux (pioctl!), while the last official
> 	release is missing many of the cleanups that were don in Linux.
> 	Not sure what to do, if someone is interested, the best way might
> 	be a fresh start with a merger of the mainline linux and the
> 	coda.cs.cmu.edu	codebase in drivers/staging.
> 	Just removing the BKL without the Coda community seems like a heap
> 	of pointless work.

Jan Harkes showed interest, looks like this will get fixed eventually,
but probably not in time for 2.6.37.

> fs/freevxfs:
> 	Uses the BKL in readdir and lookup, should be easy to fix. Christoph?

Still waiting for confirmation from Christoph Hellwig that the BKL
is not needed here. I can do the patch to remove it then.

> fs/hpfs:
> 	Looks fixable, if anyone cares. Maybe it's time for retirement in
> 	drivers/staging though. The web page only has a Link to the
> 	linux-2.2 version.

No replies.

> fs/lockd:
> 	Trond writes that he has someone working on BKL removal here.

Bryan Schumaker took care of this, looks like the locking is independent
of the fs/locks.c locking now, although it still uses the BKL internally.

I assume that this will get fixed as well, doesn't seem hard. As long
as lockd uses the BKL, both nfs and nfsd depend on the BKL implicitly.

> fs/locks.c:
> 	Patch is under discussion, blocked by work on fs/lockd currently.

No longer blocked now, both lockd and ceph can deal with this converted
to spinlocks. I will follow up with the final patch once they hit mainline.

> fs/ncpfs:
> 	Should be fixable if Petr still cares about it. Otherwise suggest
> 	moving to drivers/staging if there are no users left.

Fixed by Petr Vandrovec.

> fs/qnx4:
> 	Should be easy to fix, there are only a few places in the code that
> 	use the BKL. Anders?

Anders Larsen volunteered.

> fs/smbfs:
> 	Last I heard this was considered obsolete. Should be move it to
> 	drivers/staging now?

Now in staging.

> fs/udf:
> 	Not completely trivial, but probably necessary to fix. Project web
> 	site is dead, I hope that Jan Kara can be motivated to fix it though.

Jan Kara volunteered to do it.

> fs/ufs:
> 	Evgeniy Dushistov is maintaining this, I hope he can take care of
> 	getting rid of the BKL in UFS.

No replies.

> kernel/trace/blktrace.c:
> 	Should be easy. Ingo? Steven?

Done.

> net/appletalk:
> net/ipx/af_ipx.c:
> net/irda/af_irda.c:
> 	Can probably be saved from retirement in drivers/staging if the
> 	maintainers still care.

Samuel Ortiz fixed irda.

David Miller volunteered to do appletalk and ipx.

> net/x25:
> 	Andrew Hendry has started working on it.

Patches have shown up in -next now, I suppose Andrew will finish it soon.

Out of the remaining modules, I guess i810/i830, adfs, hpfs and ufs might end
up not getting fixed at all, we can either mark them non-SMP or move them
to drivers/staging once all the others are done.

	Arnd

  parent reply	other threads:[~2010-10-18 15:42 UTC|newest]

Thread overview: 48+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-09-16 14:32 Remaining BKL users, what to do Arnd Bergmann
2010-09-16 14:49 ` Steven Rostedt
2010-09-16 18:32   ` Jens Axboe
2010-09-17 18:46     ` Arnd Bergmann
2010-09-16 15:04 ` Jan Kara
2010-09-16 21:26   ` Anton Altaparmakov
2010-09-17 10:45     ` Arnd Bergmann
2010-09-17 13:32       ` Christoph Hellwig
2010-09-17 13:50         ` Arnd Bergmann
2010-09-17 14:02           ` Christoph Hellwig
2010-09-17 14:56             ` Arnd Bergmann
2010-09-16 15:07 ` Alan Cox
2010-09-16 20:08   ` David Miller
2010-09-16 16:09 ` Anders Larsen
2010-09-16 16:57 ` Samuel Ortiz
2010-09-16 20:08   ` David Miller
2010-09-20  1:25 ` [autofs] " Ian Kent
2010-10-18 15:42 ` Arnd Bergmann [this message]
2010-10-18 16:19   ` [v2] " Christoph Hellwig
2010-10-18 17:38     ` Arnd Bergmann
2010-10-18 18:43   ` [Ksummit-2010-discuss] " Greg KH
2010-10-18 23:00     ` Dave Airlie
2010-10-19  0:40       ` Greg KH
2010-10-19  0:57         ` Dave Airlie
2010-10-19  2:24           ` Greg KH
2010-10-19  2:45             ` Dave Airlie
2010-10-19  3:33               ` Steven Rostedt
2010-10-19  4:03                 ` Dave Airlie
2010-10-19  5:00                 ` Theodore Kilgore
2010-10-19  4:52                   ` Dave Airlie
2010-10-19  7:26                     ` Arnd Bergmann
2010-10-19 12:39                       ` Steven Rostedt
2010-10-19 13:54                         ` Paul Mundt
2010-10-19 13:26                       ` Arnd Bergmann
2010-10-19 20:50                         ` Dave Airlie
2010-10-20 16:14                           ` Ville Syrjälä
2010-10-19 18:24         ` Valdis.Kletnieks
2010-10-19 19:37           ` Greg KH
2010-10-19 19:40             ` Oliver Neukum
2010-10-19 20:29               ` Greg KH
2010-10-19 20:38                 ` Jiri Kosina
2010-10-19 20:41                 ` Alan Cox
2010-10-19 20:48                   ` Arnd Bergmann
2010-10-19 20:44                 ` Arnd Bergmann
2010-10-20  4:43                   ` Dave Young
2010-10-20  6:50                     ` Arnd Bergmann
2010-11-02  1:21                   ` Pavel Machek
2010-11-03  6:58                     ` Pekka Enberg

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