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@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/n/tip-bmrZolsbGmautmzrerog27io@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/include/linux/rwsem-spinlock.h b/include/linux/rwsem-spinlock.h
index d5b13bc..561e861 100644 (file)
--- 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 (file)
--- 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);