Messages in this thread Patch in this message | | | From | Michel Lespinasse <> | Subject | [PATCH 1/4] rwsem: make the waiter type an enumeration rather than a bitmask | Date | Fri, 8 Feb 2013 18:45:34 -0800 |
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We are not planning to add some new waiter flags, so we can convert the waiter type into an enumeration.
Background: David Howells suggested I do this back when I tried adding a new waiter type for unfair readers. However, I believe the cleanup applies regardless of that use case.
Signed-off-by: Michel Lespinasse <walken@google.com>
--- lib/rwsem.c | 19 +++++++++++-------- 1 file changed, 11 insertions(+), 8 deletions(-)
diff --git a/lib/rwsem.c b/lib/rwsem.c index 8337e1b9bb8d..4a6ff093a433 100644 --- a/lib/rwsem.c +++ b/lib/rwsem.c @@ -28,12 +28,15 @@ 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 @@ -63,7 +66,7 @@ __rwsem_do_wake(struct rw_semaphore *sem, int wake_type) signed long oldcount, 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) @@ -132,10 +135,10 @@ __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; @@ -171,7 +174,7 @@ __rwsem_do_wake(struct rw_semaphore *sem, int wake_type) */ 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; @@ -182,7 +185,7 @@ 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)) -- 1.8.1
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