locking/atomic, arch/blackfin: Implement atomic_fetch_{add,sub,and,or,xor}()
Implement FETCH-OP atomic primitives, these are very similar to the existing OP-RETURN primitives we already have, except they return the value of the atomic variable _before_ modification. This is especially useful for irreversible operations -- such as bitops (because it becomes impossible to reconstruct the state prior to modification). Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Miao <realmz6@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: adi-buildroot-devel@lists.sourceforge.net Cc: linux-arch@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
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committed by
Ingo Molnar

parent
1a6eafacd4
commit
e87fc0ec07
@@ -17,6 +17,7 @@
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asmlinkage int __raw_uncached_fetch_asm(const volatile int *ptr);
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asmlinkage int __raw_atomic_add_asm(volatile int *ptr, int value);
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asmlinkage int __raw_atomic_xadd_asm(volatile int *ptr, int value);
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asmlinkage int __raw_atomic_and_asm(volatile int *ptr, int value);
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asmlinkage int __raw_atomic_or_asm(volatile int *ptr, int value);
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@@ -28,10 +29,17 @@ asmlinkage int __raw_atomic_test_asm(const volatile int *ptr, int value);
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#define atomic_add_return(i, v) __raw_atomic_add_asm(&(v)->counter, i)
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#define atomic_sub_return(i, v) __raw_atomic_add_asm(&(v)->counter, -(i))
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#define atomic_fetch_add(i, v) __raw_atomic_xadd_asm(&(v)->counter, i)
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#define atomic_fetch_sub(i, v) __raw_atomic_xadd_asm(&(v)->counter, -(i))
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#define atomic_or(i, v) (void)__raw_atomic_or_asm(&(v)->counter, i)
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#define atomic_and(i, v) (void)__raw_atomic_and_asm(&(v)->counter, i)
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#define atomic_xor(i, v) (void)__raw_atomic_xor_asm(&(v)->counter, i)
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#define atomic_fetch_or(i, v) __raw_atomic_or_asm(&(v)->counter, i)
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#define atomic_fetch_and(i, v) __raw_atomic_and_asm(&(v)->counter, i)
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#define atomic_fetch_xor(i, v) __raw_atomic_xor_asm(&(v)->counter, i)
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#endif
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#include <asm-generic/atomic.h>
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