Commit-ID: 13b9a962a2594ee880c5d50d7f70964da1d4fe5a
Gitweb: http://git.kernel.org/tip/13b9a962a2594ee880c5d50d7f70964da1d4fe5a
Author: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
AuthorDate: Wed, 16 Jul 2014 14:54:55 +0200
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Wed, 16 Jul 2014 14:56:55 +0200
locking/rwsem: Rename 'activity' to 'count'
There are two definitions of struct rw_semaphore, one in linux/rwsem.h
and one in linux/rwsem-spinlock.h.
For some reason they have different names for the initial field. This
makes it impossible to use C99 named initialization for
__RWSEM_INITIALIZER() -- or we have to duplicate that entire thing
along with the structure definitions.
The simpler patch is renaming the rwsem-spinlock variant to match the
regular rwsem.
This allows us to switch to C99 named initialization.
Signed-off-by: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Link: http://lkml.kernel.org/n/tip-bmrZolsbGmautmzrerog27io@xxxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
include/linux/rwsem-spinlock.h | 8 ++++----
kernel/locking/rwsem-spinlock.c | 28 ++++++++++++++--------------
2 files changed, 18 insertions(+), 18 deletions(-)
diff --git a/include/linux/rwsem-spinlock.h b/include/linux/rwsem-spinlock.h
index d5b13bc..561e861 100644
--- a/include/linux/rwsem-spinlock.h
+++ b/include/linux/rwsem-spinlock.h
@@ -15,13 +15,13 @@
#ifdef __KERNEL__
/*
* the rw-semaphore definition
- * - if activity is 0 then there are no active readers or writers
- * - if activity is +ve then that is the number of active readers
- * - if activity is -1 then there is one active writer
+ * - if count is 0 then there are no active readers or writers
+ * - if count is +ve then that is the number of active readers
+ * - if count is -1 then there is one active writer
* - if wait_list is not empty, then there are processes waiting for the semaphore
*/
struct rw_semaphore {
- __s32 activity;
+ __s32 count;
raw_spinlock_t wait_lock;
struct list_head wait_list;
#ifdef CONFIG_DEBUG_LOCK_ALLOC
diff --git a/kernel/locking/rwsem-spinlock.c b/kernel/locking/rwsem-spinlock.c
index 9be8a91..2c93571 100644
--- a/kernel/locking/rwsem-spinlock.c
+++ b/kernel/locking/rwsem-spinlock.c
@@ -26,7 +26,7 @@ int rwsem_is_locked(struct rw_semaphore *sem)
unsigned long flags;
if (raw_spin_trylock_irqsave(&sem->wait_lock, flags)) {
- ret = (sem->activity != 0);
+ ret = (sem->count != 0);
raw_spin_unlock_irqrestore(&sem->wait_lock, flags);
}
return ret;
@@ -46,7 +46,7 @@ void __init_rwsem(struct rw_semaphore *sem, const char *name,
debug_check_no_locks_freed((void *)sem, sizeof(*sem));
lockdep_init_map(&sem->dep_map, name, key, 0);
#endif
- sem->activity = 0;
+ sem->count = 0;
raw_spin_lock_init(&sem->wait_lock);
INIT_LIST_HEAD(&sem->wait_list);
}
@@ -95,7 +95,7 @@ __rwsem_do_wake(struct rw_semaphore *sem, int wakewrite)
waiter = list_entry(next, struct rwsem_waiter, list);
} while (waiter->type != RWSEM_WAITING_FOR_WRITE);
- sem->activity += woken;
+ sem->count += woken;
out:
return sem;
@@ -126,9 +126,9 @@ void __sched __down_read(struct rw_semaphore *sem)
raw_spin_lock_irqsave(&sem->wait_lock, flags);
- if (sem->activity >= 0 && list_empty(&sem->wait_list)) {
+ if (sem->count >= 0 && list_empty(&sem->wait_list)) {
/* granted */
- sem->activity++;
+ sem->count++;
raw_spin_unlock_irqrestore(&sem->wait_lock, flags);
goto out;
}
@@ -170,9 +170,9 @@ int __down_read_trylock(struct rw_semaphore *sem)
raw_spin_lock_irqsave(&sem->wait_lock, flags);
- if (sem->activity >= 0 && list_empty(&sem->wait_list)) {
+ if (sem->count >= 0 && list_empty(&sem->wait_list)) {
/* granted */
- sem->activity++;
+ sem->count++;
ret = 1;
}
@@ -206,7 +206,7 @@ void __sched __down_write_nested(struct rw_semaphore *sem, int subclass)
* itself into sleep and waiting for system woke it or someone
* else in the head of the wait list up.
*/
- if (sem->activity == 0)
+ if (sem->count == 0)
break;
set_task_state(tsk, TASK_UNINTERRUPTIBLE);
raw_spin_unlock_irqrestore(&sem->wait_lock, flags);
@@ -214,7 +214,7 @@ void __sched __down_write_nested(struct rw_semaphore *sem, int subclass)
raw_spin_lock_irqsave(&sem->wait_lock, flags);
}
/* got the lock */
- sem->activity = -1;
+ sem->count = -1;
list_del(&waiter.list);
raw_spin_unlock_irqrestore(&sem->wait_lock, flags);
@@ -235,9 +235,9 @@ int __down_write_trylock(struct rw_semaphore *sem)
raw_spin_lock_irqsave(&sem->wait_lock, flags);
- if (sem->activity == 0) {
+ if (sem->count == 0) {
/* got the lock */
- sem->activity = -1;
+ sem->count = -1;
ret = 1;
}
@@ -255,7 +255,7 @@ void __up_read(struct rw_semaphore *sem)
raw_spin_lock_irqsave(&sem->wait_lock, flags);
- if (--sem->activity == 0 && !list_empty(&sem->wait_list))
+ if (--sem->count == 0 && !list_empty(&sem->wait_list))
sem = __rwsem_wake_one_writer(sem);
raw_spin_unlock_irqrestore(&sem->wait_lock, flags);
@@ -270,7 +270,7 @@ void __up_write(struct rw_semaphore *sem)
raw_spin_lock_irqsave(&sem->wait_lock, flags);
- sem->activity = 0;
+ sem->count = 0;
if (!list_empty(&sem->wait_list))
sem = __rwsem_do_wake(sem, 1);
@@ -287,7 +287,7 @@ void __downgrade_write(struct rw_semaphore *sem)
raw_spin_lock_irqsave(&sem->wait_lock, flags);
- sem->activity = 1;
+ sem->count = 1;
if (!list_empty(&sem->wait_list))
sem = __rwsem_do_wake(sem, 0);
--
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