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authorJason Low <jason.low2@hpe.com>2016-06-03 22:26:02 -0700
committerIngo Molnar <mingo@kernel.org>2016-06-08 15:16:42 +0200
commit8ee62b1870be8e630158701632a533d0378e15b8 (patch)
tree18f68e695ee974f059703e75957e201695049cb9 /include/linux/rwsem.h
parent055ce0fd1b86c204430cbc0887165599d6e15090 (diff)
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>
Diffstat (limited to 'include/linux/rwsem.h')
-rw-r--r--include/linux/rwsem.h8
1 files changed, 5 insertions, 3 deletions
diff --git a/include/linux/rwsem.h b/include/linux/rwsem.h
index d37fbb34d06f..dd1d14250340 100644
--- a/include/linux/rwsem.h
+++ b/include/linux/rwsem.h
@@ -23,10 +23,11 @@ struct rw_semaphore;
#ifdef CONFIG_RWSEM_GENERIC_SPINLOCK
#include <linux/rwsem-spinlock.h> /* use a generic implementation */
+#define __RWSEM_INIT_COUNT(name) .count = RWSEM_UNLOCKED_VALUE
#else
/* All arch specific implementations share the same struct */
struct rw_semaphore {
- long count;
+ atomic_long_t count;
struct list_head wait_list;
raw_spinlock_t wait_lock;
#ifdef CONFIG_RWSEM_SPIN_ON_OWNER
@@ -54,9 +55,10 @@ extern struct rw_semaphore *rwsem_downgrade_wake(struct rw_semaphore *sem);
/* In all implementations count != 0 means locked */
static inline int rwsem_is_locked(struct rw_semaphore *sem)
{
- return sem->count != 0;
+ return atomic_long_read(&sem->count) != 0;
}
+#define __RWSEM_INIT_COUNT(name) .count = ATOMIC_LONG_INIT(RWSEM_UNLOCKED_VALUE)
#endif
/* Common initializer macros and functions */
@@ -74,7 +76,7 @@ static inline int rwsem_is_locked(struct rw_semaphore *sem)
#endif
#define __RWSEM_INITIALIZER(name) \
- { .count = RWSEM_UNLOCKED_VALUE, \
+ { __RWSEM_INIT_COUNT(name), \
.wait_list = LIST_HEAD_INIT((name).wait_list), \
.wait_lock = __RAW_SPIN_LOCK_UNLOCKED(name.wait_lock) \
__RWSEM_OPT_INIT(name) \