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
