locking/rwsem: Use task->state helpers

Call __set_task_state() instead of assigning the new state
directly. These interfaces also aid CONFIG_DEBUG_ATOMIC_SLEEP
environments, keeping track of who last changed the state.

Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Jason Low <jason.low2@hp.com>
Cc: Michel Lespinasse <walken@google.com>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1422257769-14083-2-git-send-email-dave@stgolabs.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>

kernel/locking/rwsem-spinlock.c

@@ -154,7 +154,7 @@ void __sched __down_read(struct rw_semaphore *sem)
 		set_task_state(tsk, TASK_UNINTERRUPTIBLE);
 	}
 
-	tsk->state = TASK_RUNNING;
+	__set_task_state(tsk, TASK_RUNNING);
  out:
 	;
 }

kernel/locking/rwsem-xadd.c

@@ -242,8 +242,7 @@ struct rw_semaphore __sched *rwsem_down_read_failed(struct rw_semaphore *sem)
 		schedule();
 	}
 
-	tsk->state = TASK_RUNNING;
-
+	__set_task_state(tsk, TASK_RUNNING);
 	return sem;
 }
 EXPORT_SYMBOL(rwsem_down_read_failed);