37a9d912b2
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>
111 lines
1.8 KiB
C
111 lines
1.8 KiB
C
#ifndef __ASM_SH_FUTEX_IRQ_H
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#define __ASM_SH_FUTEX_IRQ_H
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#include <asm/system.h>
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static inline int atomic_futex_op_xchg_set(int oparg, int __user *uaddr,
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int *oldval)
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{
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unsigned long flags;
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int ret;
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local_irq_save(flags);
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ret = get_user(*oldval, uaddr);
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if (!ret)
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ret = put_user(oparg, uaddr);
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local_irq_restore(flags);
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return ret;
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}
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static inline int atomic_futex_op_xchg_add(int oparg, int __user *uaddr,
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int *oldval)
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{
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unsigned long flags;
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int ret;
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local_irq_save(flags);
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ret = get_user(*oldval, uaddr);
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if (!ret)
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ret = put_user(*oldval + oparg, uaddr);
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local_irq_restore(flags);
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return ret;
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}
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static inline int atomic_futex_op_xchg_or(int oparg, int __user *uaddr,
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int *oldval)
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{
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unsigned long flags;
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int ret;
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local_irq_save(flags);
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ret = get_user(*oldval, uaddr);
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if (!ret)
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ret = put_user(*oldval | oparg, uaddr);
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local_irq_restore(flags);
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return ret;
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}
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static inline int atomic_futex_op_xchg_and(int oparg, int __user *uaddr,
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int *oldval)
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{
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unsigned long flags;
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int ret;
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local_irq_save(flags);
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ret = get_user(*oldval, uaddr);
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if (!ret)
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ret = put_user(*oldval & oparg, uaddr);
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local_irq_restore(flags);
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return ret;
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}
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static inline int atomic_futex_op_xchg_xor(int oparg, int __user *uaddr,
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int *oldval)
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{
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unsigned long flags;
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int ret;
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local_irq_save(flags);
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ret = get_user(*oldval, uaddr);
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if (!ret)
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ret = put_user(*oldval ^ oparg, uaddr);
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local_irq_restore(flags);
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return ret;
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}
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static inline int atomic_futex_op_cmpxchg_inatomic(int *uval,
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int __user *uaddr,
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int oldval, int newval)
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{
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unsigned long flags;
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int ret, prev = 0;
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local_irq_save(flags);
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ret = get_user(prev, uaddr);
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if (!ret && oldval == prev)
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ret = put_user(newval, uaddr);
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local_irq_restore(flags);
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*uval = prev;
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return ret;
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}
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#endif /* __ASM_SH_FUTEX_IRQ_H */
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