Commit b106bcf0 authored by David Laight's avatar David Laight Committed by Linus Torvalds
Browse files

locking/osq_lock: Clarify osq_wait_next() 



Directly return NULL or 'next' instead of breaking out of the loop.

Signed-off-by: default avatarDavid Laight <david.laight@aculab.com>
[ Split original patch into two independent parts  - Linus ]
Link: https://lore.kernel.org/lkml/7c8828aec72e42eeb841ca0ee3397e9a@AcuMS.aculab.com/


Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 563adbfc

kernel/locking/osq_lock.c

+4 −5
Original line number Diff line number Diff line
@@ -55,7 +55,6 @@ osq_wait_next(struct optimistic_spin_queue *lock, 
	      struct optimistic_spin_node *node,

	      int old_cpu)

{

	struct optimistic_spin_node *next = NULL;

	int curr = encode_cpu(smp_processor_id());



	for (;;) {
@@ -66,7 +65,7 @@ osq_wait_next(struct optimistic_spin_queue *lock, 
			 * will now observe @lock and will complete its

			 * unlock()/unqueue().

			 */

			break;

			return NULL;

		}



		/*
@@ -80,15 +79,15 @@ osq_wait_next(struct optimistic_spin_queue *lock, 
		 * wait for a new @node->next from its Step-C.

		 */

		if (node->next) {

			struct optimistic_spin_node *next;



			next = xchg(&node->next, NULL);

			if (next)

				break;

				return next;

		}



		cpu_relax();

	}



	return next;

}



bool osq_lock(struct optimistic_spin_queue *lock)