Michel Lespinasse 37a9d912b2 futex: Sanitize cmpxchg_futex_value_locked API
The cmpxchg_futex_value_locked API was funny in that it returned either
the original, user-exposed futex value OR an error code such as -EFAULT.
This was confusing at best, and could be a source of livelocks in places
that retry the cmpxchg_futex_value_locked after trying to fix the issue
by running fault_in_user_writeable().
    
This change makes the cmpxchg_futex_value_locked API more similar to the
get_futex_value_locked one, returning an error code and updating the
original value through a reference argument.
    
Signed-off-by: Michel Lespinasse <walken@google.com>
Acked-by: Chris Metcalf <cmetcalf@tilera.com>  [tile]
Acked-by: Tony Luck <tony.luck@intel.com>  [ia64]
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Michal Simek <monstr@monstr.eu>  [microblaze]
Acked-by: David Howells <dhowells@redhat.com> [frv]
Cc: Darren Hart <darren@dvhart.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
LKML-Reference: <20110311024851.GC26122@google.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-03-11 12:23:08 +01:00
..
2010-08-04 10:26:03 +10:00
2010-11-29 15:48:22 +11:00
2009-12-10 20:08:15 -06:00
2010-10-26 16:52:08 -07:00
2010-11-29 15:48:22 +11:00
2010-10-07 14:08:55 +01:00
2008-08-18 21:40:03 +02:00
2008-08-04 13:18:17 +10:00
2010-08-14 22:26:51 +02:00
2010-05-17 12:18:23 +03:00
2010-05-17 12:18:21 +03:00
2010-03-01 12:36:06 -03:00
2010-06-09 11:12:36 +02:00
2010-05-05 09:11:10 -04:00
2010-11-29 15:48:21 +11:00
2010-03-05 03:04:08 -06:00
2010-10-26 16:52:08 -07:00
2010-10-26 16:52:08 -07:00
2009-04-07 15:18:58 +10:00
2009-12-09 17:10:37 +11:00
2010-03-05 03:04:08 -06:00
2010-08-24 14:41:48 +10:00
2008-10-15 11:31:54 +11:00
2010-06-28 12:41:33 -07:00
2008-09-06 19:30:15 +01:00
2009-04-01 08:59:16 -07:00
2009-08-28 14:24:10 +10:00