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

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>

1 files changed, 13 insertions, 13 deletions

diff --git a/arch/alpha/include/asm/rwsem.h b/arch/alpha/include/asm/rwsem.h
index 0131a7058778..b40021aabb9f 100644
--- a/arch/alpha/include/asm/rwsem.h
+++ b/arch/alpha/include/asm/rwsem.h
@@ -25,8 +25,8 @@ static inline void __down_read(struct rw_semaphore *sem)
 {
         long oldcount;
 #ifndef CONFIG_SMP
-        oldcount = sem->count;
-        sem->count += RWSEM_ACTIVE_READ_BIAS;
+        oldcount = sem->count.counter;
+        sem->count.counter += RWSEM_ACTIVE_READ_BIAS;
 #else
         long temp;
         __asm__ __volatile__(
@@ -52,13 +52,13 @@ static inline int __down_read_trylock(struct rw_semaphore *sem)
 {
         long old, new, res;
 
-        res = sem->count;
+        res = atomic_long_read(&sem->count);
         do {
                 new = res + RWSEM_ACTIVE_READ_BIAS;
                 if (new <= 0)
                         break;
                 old = res;
-                res = cmpxchg(&sem->count, old, new);
+                res = atomic_long_cmpxchg(&sem->count, old, new);
         } while (res != old);
         return res >= 0 ? 1 : 0;
 }
@@ -67,8 +67,8 @@ static inline long ___down_write(struct rw_semaphore *sem)
 {
         long oldcount;
 #ifndef CONFIG_SMP
-        oldcount = sem->count;
-        sem->count += RWSEM_ACTIVE_WRITE_BIAS;
+        oldcount = sem->count.counter;
+        sem->count.counter += RWSEM_ACTIVE_WRITE_BIAS;
 #else
         long temp;
         __asm__ __volatile__(
@@ -106,7 +106,7 @@ static inline int __down_write_killable(struct rw_semaphore *sem)
  */
 static inline int __down_write_trylock(struct rw_semaphore *sem)
 {
-        long ret = cmpxchg(&sem->count, RWSEM_UNLOCKED_VALUE,
+        long ret = atomic_long_cmpxchg(&sem->count, RWSEM_UNLOCKED_VALUE,
                            RWSEM_ACTIVE_WRITE_BIAS);
         if (ret == RWSEM_UNLOCKED_VALUE)
                 return 1;
@@ -117,8 +117,8 @@ static inline void __up_read(struct rw_semaphore *sem)
 {
         long oldcount;
 #ifndef CONFIG_SMP
-        oldcount = sem->count;
-        sem->count -= RWSEM_ACTIVE_READ_BIAS;
+        oldcount = sem->count.counter;
+        sem->count.counter -= RWSEM_ACTIVE_READ_BIAS;
 #else
         long temp;
         __asm__ __volatile__(
@@ -142,8 +142,8 @@ static inline void __up_write(struct rw_semaphore *sem)
 {
         long count;
 #ifndef CONFIG_SMP
-        sem->count -= RWSEM_ACTIVE_WRITE_BIAS;
-        count = sem->count;
+        sem->count.counter -= RWSEM_ACTIVE_WRITE_BIAS;
+        count = sem->count.counter;
 #else
         long temp;
         __asm__ __volatile__(
@@ -171,8 +171,8 @@ static inline void __downgrade_write(struct rw_semaphore *sem)
 {
         long oldcount;
 #ifndef CONFIG_SMP
-        oldcount = sem->count;
-        sem->count -= RWSEM_WAITING_BIAS;
+        oldcount = sem->count.counter;
+        sem->count.counter -= RWSEM_WAITING_BIAS;
 #else
         long temp;
         __asm__ __volatile__(