diff options
| -rw-r--r-- | lib/rwsem-spinlock.c | 19 | ||||
| -rw-r--r-- | lib/rwsem.c | 23 |
2 files changed, 24 insertions, 18 deletions
diff --git a/lib/rwsem-spinlock.c b/lib/rwsem-spinlock.c index 7542afbb22b..5f117f37ac0 100644 --- a/lib/rwsem-spinlock.c +++ b/lib/rwsem-spinlock.c @@ -9,12 +9,15 @@ #include <linux/sched.h> #include <linux/export.h> +enum rwsem_waiter_type { + RWSEM_WAITING_FOR_WRITE, + RWSEM_WAITING_FOR_READ +}; + struct rwsem_waiter { struct list_head list; struct task_struct *task; - unsigned int flags; -#define RWSEM_WAITING_FOR_READ 0x00000001 -#define RWSEM_WAITING_FOR_WRITE 0x00000002 + enum rwsem_waiter_type type; }; int rwsem_is_locked(struct rw_semaphore *sem) @@ -68,7 +71,7 @@ __rwsem_do_wake(struct rw_semaphore *sem, int wakewrite) waiter = list_entry(sem->wait_list.next, struct rwsem_waiter, list); if (!wakewrite) { - if (waiter->flags & RWSEM_WAITING_FOR_WRITE) + if (waiter->type == RWSEM_WAITING_FOR_WRITE) goto out; goto dont_wake_writers; } @@ -78,7 +81,7 @@ __rwsem_do_wake(struct rw_semaphore *sem, int wakewrite) * to -1 here to indicate we get the lock. Instead, we wake it up * to let it go get it again. */ - if (waiter->flags & RWSEM_WAITING_FOR_WRITE) { + if (waiter->type == RWSEM_WAITING_FOR_WRITE) { wake_up_process(waiter->task); goto out; } @@ -86,7 +89,7 @@ __rwsem_do_wake(struct rw_semaphore *sem, int wakewrite) /* grant an infinite number of read locks to the front of the queue */ dont_wake_writers: woken = 0; - while (waiter->flags & RWSEM_WAITING_FOR_READ) { + while (waiter->type == RWSEM_WAITING_FOR_READ) { struct list_head *next = waiter->list.next; list_del(&waiter->list); @@ -144,7 +147,7 @@ void __sched __down_read(struct rw_semaphore *sem) /* set up my own style of waitqueue */ waiter.task = tsk; - waiter.flags = RWSEM_WAITING_FOR_READ; + waiter.type = RWSEM_WAITING_FOR_READ; get_task_struct(tsk); list_add_tail(&waiter.list, &sem->wait_list); @@ -201,7 +204,7 @@ void __sched __down_write_nested(struct rw_semaphore *sem, int subclass) /* set up my own style of waitqueue */ tsk = current; waiter.task = tsk; - waiter.flags = RWSEM_WAITING_FOR_WRITE; + waiter.type = RWSEM_WAITING_FOR_WRITE; list_add_tail(&waiter.list, &sem->wait_list); /* wait for someone to release the lock */ diff --git a/lib/rwsem.c b/lib/rwsem.c index ad5e0df16ab..672eb33218a 100644 --- a/lib/rwsem.c +++ b/lib/rwsem.c @@ -30,12 +30,15 @@ void __init_rwsem(struct rw_semaphore *sem, const char *name, EXPORT_SYMBOL(__init_rwsem); +enum rwsem_waiter_type { + RWSEM_WAITING_FOR_WRITE, + RWSEM_WAITING_FOR_READ +}; + struct rwsem_waiter { struct list_head list; struct task_struct *task; - unsigned int flags; -#define RWSEM_WAITING_FOR_READ 0x00000001 -#define RWSEM_WAITING_FOR_WRITE 0x00000002 + enum rwsem_waiter_type type; }; /* Wake types for __rwsem_do_wake(). Note that RWSEM_WAKE_NO_ACTIVE and @@ -65,7 +68,7 @@ __rwsem_do_wake(struct rw_semaphore *sem, int wake_type) signed long woken, loop, adjustment; waiter = list_entry(sem->wait_list.next, struct rwsem_waiter, list); - if (!(waiter->flags & RWSEM_WAITING_FOR_WRITE)) + if (waiter->type != RWSEM_WAITING_FOR_WRITE) goto readers_only; if (wake_type == RWSEM_WAKE_READ_OWNED) @@ -112,10 +115,10 @@ __rwsem_do_wake(struct rw_semaphore *sem, int wake_type) waiter = list_entry(waiter->list.next, struct rwsem_waiter, list); - } while (waiter->flags & RWSEM_WAITING_FOR_READ); + } while (waiter->type != RWSEM_WAITING_FOR_WRITE); adjustment = woken * RWSEM_ACTIVE_READ_BIAS; - if (waiter->flags & RWSEM_WAITING_FOR_READ) + if (waiter->type != RWSEM_WAITING_FOR_WRITE) /* hit end of list above */ adjustment -= RWSEM_WAITING_BIAS; @@ -148,7 +151,7 @@ static int try_get_writer_sem(struct rw_semaphore *sem, /* only steal when first waiter is writing */ fwaiter = list_entry(sem->wait_list.next, struct rwsem_waiter, list); - if (!(fwaiter->flags & RWSEM_WAITING_FOR_WRITE)) + if (fwaiter->type != RWSEM_WAITING_FOR_WRITE) return 0; adjustment = RWSEM_ACTIVE_WRITE_BIAS; @@ -179,7 +182,7 @@ try_again_write: */ static struct rw_semaphore __sched * rwsem_down_failed_common(struct rw_semaphore *sem, - unsigned int flags, signed long adjustment) + enum rwsem_waiter_type type, signed long adjustment) { struct rwsem_waiter waiter; struct task_struct *tsk = current; @@ -190,7 +193,7 @@ rwsem_down_failed_common(struct rw_semaphore *sem, /* set up my own style of waitqueue */ raw_spin_lock_irq(&sem->wait_lock); waiter.task = tsk; - waiter.flags = flags; + waiter.type = type; get_task_struct(tsk); if (list_empty(&sem->wait_list)) @@ -221,7 +224,7 @@ rwsem_down_failed_common(struct rw_semaphore *sem, raw_spin_lock_irq(&sem->wait_lock); /* Try to get the writer sem, may steal from the head writer: */ - if (flags == RWSEM_WAITING_FOR_WRITE) + if (type == RWSEM_WAITING_FOR_WRITE) if (try_get_writer_sem(sem, &waiter)) { raw_spin_unlock_irq(&sem->wait_lock); return sem; |