6aa7de0591
Please do not apply this to mainline directly, instead please re-run the
coccinelle script shown below and apply its output.
For several reasons, it is desirable to use {READ,WRITE}_ONCE() in
preference to ACCESS_ONCE(), and new code is expected to use one of the
former. So far, there's been no reason to change most existing uses of
ACCESS_ONCE(), as these aren't harmful, and changing them results in
churn.
However, for some features, the read/write distinction is critical to
correct operation. To distinguish these cases, separate read/write
accessors must be used. This patch migrates (most) remaining
ACCESS_ONCE() instances to {READ,WRITE}_ONCE(), using the following
coccinelle script:
----
// Convert trivial ACCESS_ONCE() uses to equivalent READ_ONCE() and
// WRITE_ONCE()
// $ make coccicheck COCCI=/home/mark/once.cocci SPFLAGS="--include-headers" MODE=patch
virtual patch
@ depends on patch @
expression E1, E2;
@@
- ACCESS_ONCE(E1) = E2
+ WRITE_ONCE(E1, E2)
@ depends on patch @
expression E;
@@
- ACCESS_ONCE(E)
+ READ_ONCE(E)
----
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: davem@davemloft.net
Cc: linux-arch@vger.kernel.org
Cc: mpe@ellerman.id.au
Cc: shuah@kernel.org
Cc: snitzer@redhat.com
Cc: thor.thayer@linux.intel.com
Cc: tj@kernel.org
Cc: viro@zeniv.linux.org.uk
Cc: will.deacon@arm.com
Link: http://lkml.kernel.org/r/1508792849-3115-19-git-send-email-paulmck@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
66 lines
2.2 KiB
C
66 lines
2.2 KiB
C
/* atomic.h: These still suck, but the I-cache hit rate is higher.
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*
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* Copyright (C) 1996 David S. Miller (davem@davemloft.net)
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* Copyright (C) 2000 Anton Blanchard (anton@linuxcare.com.au)
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* Copyright (C) 2007 Kyle McMartin (kyle@parisc-linux.org)
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*
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* Additions by Keith M Wesolowski (wesolows@foobazco.org) based
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* on asm-parisc/atomic.h Copyright (C) 2000 Philipp Rumpf <prumpf@tux.org>.
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*/
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#ifndef __ARCH_SPARC_ATOMIC__
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#define __ARCH_SPARC_ATOMIC__
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#include <linux/types.h>
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#include <asm/cmpxchg.h>
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#include <asm/barrier.h>
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#include <asm-generic/atomic64.h>
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#define ATOMIC_INIT(i) { (i) }
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int atomic_add_return(int, atomic_t *);
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int atomic_fetch_add(int, atomic_t *);
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int atomic_fetch_and(int, atomic_t *);
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int atomic_fetch_or(int, atomic_t *);
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int atomic_fetch_xor(int, atomic_t *);
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int atomic_cmpxchg(atomic_t *, int, int);
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int atomic_xchg(atomic_t *, int);
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int __atomic_add_unless(atomic_t *, int, int);
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void atomic_set(atomic_t *, int);
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#define atomic_set_release(v, i) atomic_set((v), (i))
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#define atomic_read(v) READ_ONCE((v)->counter)
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#define atomic_add(i, v) ((void)atomic_add_return( (int)(i), (v)))
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#define atomic_sub(i, v) ((void)atomic_add_return(-(int)(i), (v)))
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#define atomic_inc(v) ((void)atomic_add_return( 1, (v)))
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#define atomic_dec(v) ((void)atomic_add_return( -1, (v)))
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#define atomic_and(i, v) ((void)atomic_fetch_and((i), (v)))
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#define atomic_or(i, v) ((void)atomic_fetch_or((i), (v)))
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#define atomic_xor(i, v) ((void)atomic_fetch_xor((i), (v)))
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#define atomic_sub_return(i, v) (atomic_add_return(-(int)(i), (v)))
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#define atomic_fetch_sub(i, v) (atomic_fetch_add (-(int)(i), (v)))
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#define atomic_inc_return(v) (atomic_add_return( 1, (v)))
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#define atomic_dec_return(v) (atomic_add_return( -1, (v)))
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#define atomic_add_negative(a, v) (atomic_add_return((a), (v)) < 0)
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/*
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* atomic_inc_and_test - increment and test
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* @v: pointer of type atomic_t
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*
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* Atomically increments @v by 1
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* and returns true if the result is zero, or false for all
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* other cases.
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*/
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#define atomic_inc_and_test(v) (atomic_inc_return(v) == 0)
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#define atomic_dec_and_test(v) (atomic_dec_return(v) == 0)
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#define atomic_sub_and_test(i, v) (atomic_sub_return(i, v) == 0)
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#endif /* !(__ARCH_SPARC_ATOMIC__) */
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