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locking/atomic, arch/tile: Implement atomic{,64}_fetch_{add,sub,and,or,xor}()

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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>
Acked-by: Chris Metcalf <cmetcalf@mellanox.com>
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: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-arch@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Peter Zijlstra
2016-04-18 01:16:03 +02:00
committed by Ingo Molnar
parent 3a1adb23a5
commit 1af5de9af1
6 changed files with 164 additions and 99 deletions
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18
arch/tile/include/asm/bitops_32.h
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@@ -19,9 +19,9 @@
#include <asm/barrier.h>
/* Tile-specific routines to support <asm/bitops.h>. */
unsigned long _atomic_or(volatile unsigned long *p, unsigned long mask);
unsigned long _atomic_andn(volatile unsigned long *p, unsigned long mask);
unsigned long _atomic_xor(volatile unsigned long *p, unsigned long mask);
unsigned long _atomic_fetch_or(volatile unsigned long *p, unsigned long mask);
unsigned long _atomic_fetch_andn(volatile unsigned long *p, unsigned long mask);
unsigned long _atomic_fetch_xor(volatile unsigned long *p, unsigned long mask);
/**
* set_bit - Atomically set a bit in memory
@@ -35,7 +35,7 @@ unsigned long _atomic_xor(volatile unsigned long *p, unsigned long mask);
*/
static inline void set_bit(unsigned nr, volatile unsigned long *addr)
{
_atomic_or(addr + BIT_WORD(nr), BIT_MASK(nr));
_atomic_fetch_or(addr + BIT_WORD(nr), BIT_MASK(nr));
}
/**
@@ -54,7 +54,7 @@ static inline void set_bit(unsigned nr, volatile unsigned long *addr)
*/
static inline void clear_bit(unsigned nr, volatile unsigned long *addr)
{
_atomic_andn(addr + BIT_WORD(nr), BIT_MASK(nr));
_atomic_fetch_andn(addr + BIT_WORD(nr), BIT_MASK(nr));
}
/**
@@ -69,7 +69,7 @@ static inline void clear_bit(unsigned nr, volatile unsigned long *addr)
*/
static inline void change_bit(unsigned nr, volatile unsigned long *addr)
{
_atomic_xor(addr + BIT_WORD(nr), BIT_MASK(nr));
_atomic_fetch_xor(addr + BIT_WORD(nr), BIT_MASK(nr));
}
/**
@@ -85,7 +85,7 @@ static inline int test_and_set_bit(unsigned nr, volatile unsigned long *addr)
unsigned long mask = BIT_MASK(nr);
addr += BIT_WORD(nr);
smp_mb(); /* barrier for proper semantics */
return (_atomic_or(addr, mask) & mask) != 0;
return (_atomic_fetch_or(addr, mask) & mask) != 0;
}
/**
@@ -101,7 +101,7 @@ static inline int test_and_clear_bit(unsigned nr, volatile unsigned long *addr)
unsigned long mask = BIT_MASK(nr);
addr += BIT_WORD(nr);
smp_mb(); /* barrier for proper semantics */
return (_atomic_andn(addr, mask) & mask) != 0;
return (_atomic_fetch_andn(addr, mask) & mask) != 0;
}
/**
@@ -118,7 +118,7 @@ static inline int test_and_change_bit(unsigned nr,
unsigned long mask = BIT_MASK(nr);
addr += BIT_WORD(nr);
smp_mb(); /* barrier for proper semantics */
return (_atomic_xor(addr, mask) & mask) != 0;
return (_atomic_fetch_xor(addr, mask) & mask) != 0;
}
#include <asm-generic/bitops/ext2-atomic.h>