GitHub-Mirror/linux-bl808
2
0
Fork 0
mirror of https://github.com/Fishwaldo/linux-bl808.git synced 2025-06-17 20:25:19 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions

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

Browse source 
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

8
include/linux/rwsem.h
View file

@ -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) \