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locking/rwsem: Convert sem->count to 'atomic_long_t'

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Convert the rwsem count variable to an atomic_long_t since we use it
as an atomic variable. This also allows us to remove the
rwsem_atomic_{add,update}() "abstraction" which would now be an unnecesary
level of indirection. In follow up patches, we also remove the
rwsem_atomic_{add,update}() definitions across the various architectures.

Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Jason Low <jason.low2@hpe.com>
[ Build warning fixes on various architectures. ]
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Jason Low <jason.low2@hp.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Hurley <peter@hurleysoftware.com>
Cc: Terry Rudd <terry.rudd@hpe.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Waiman Long <Waiman.Long@hpe.com>
Link: http://lkml.kernel.org/r/1465017963-4839-2-git-send-email-jason.low2@hpe.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Jason Low
2016-06-03 22:26:02 -07:00
committed by Ingo Molnar
parent 055ce0fd1b
commit 8ee62b1870
5 changed files with 50 additions and 46 deletions
Download Patch File Download Diff File Expand all files Collapse all files

24
arch/ia64/include/asm/rwsem.h
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@@ -40,7 +40,7 @@
static inline void
__down_read (struct rw_semaphore *sem)
{
long result = ia64_fetchadd8_acq((unsigned long *)&sem->count, 1);
long result = ia64_fetchadd8_acq((unsigned long *)&sem->count.counter, 1);
if (result < 0)
rwsem_down_read_failed(sem);
@@ -55,9 +55,9 @@ ___down_write (struct rw_semaphore *sem)
long old, new;
do {
old = sem->count;
old = atomic_long_read(&sem->count);
new = old + RWSEM_ACTIVE_WRITE_BIAS;
} while (cmpxchg_acq(&sem->count, old, new) != old);
} while (atomic_long_cmpxchg_acquire(&sem->count, old, new) != old);
return old;
}
@@ -85,7 +85,7 @@ __down_write_killable (struct rw_semaphore *sem)
static inline void
__up_read (struct rw_semaphore *sem)
{
long result = ia64_fetchadd8_rel((unsigned long *)&sem->count, -1);
long result = ia64_fetchadd8_rel((unsigned long *)&sem->count.counter, -1);
if (result < 0 && (--result & RWSEM_ACTIVE_MASK) == 0)
rwsem_wake(sem);
@@ -100,9 +100,9 @@ __up_write (struct rw_semaphore *sem)
long old, new;
do {
old = sem->count;
old = atomic_long_read(&sem->count);
new = old - RWSEM_ACTIVE_WRITE_BIAS;
} while (cmpxchg_rel(&sem->count, old, new) != old);
} while (atomic_long_cmpxchg_release(&sem->count, old, new) != old);
if (new < 0 && (new & RWSEM_ACTIVE_MASK) == 0)
rwsem_wake(sem);
@@ -115,8 +115,8 @@ static inline int
__down_read_trylock (struct rw_semaphore *sem)
{
long tmp;
while ((tmp = sem->count) >= 0) {
if (tmp == cmpxchg_acq(&sem->count, tmp, tmp+1)) {
while ((tmp = atomic_long_read(&sem->count)) >= 0) {
if (tmp == atomic_long_cmpxchg_acquire(&sem->count, tmp, tmp+1)) {
return 1;
}
}
@@ -129,8 +129,8 @@ __down_read_trylock (struct rw_semaphore *sem)
static inline int
__down_write_trylock (struct rw_semaphore *sem)
{
long tmp = cmpxchg_acq(&sem->count, RWSEM_UNLOCKED_VALUE,
RWSEM_ACTIVE_WRITE_BIAS);
long tmp = atomic_long_cmpxchg_acquire(&sem->count,
RWSEM_UNLOCKED_VALUE, RWSEM_ACTIVE_WRITE_BIAS);
return tmp == RWSEM_UNLOCKED_VALUE;
}
@@ -143,9 +143,9 @@ __downgrade_write (struct rw_semaphore *sem)
long old, new;
do {
old = sem->count;
old = atomic_long_read(&sem->count);
new = old - RWSEM_WAITING_BIAS;
} while (cmpxchg_rel(&sem->count, old, new) != old);
} while (atomic_long_cmpxchg_release(&sem->count, old, new) != old);
if (old < 0)
rwsem_downgrade_wake(sem);