From b106bcf0f99ae0459f3c8c2f0af575ef9f5d9bde Mon Sep 17 00:00:00 2001 From: David Laight Date: Fri, 29 Dec 2023 20:56:03 +0000 Subject: [PATCH] locking/osq_lock: Clarify osq_wait_next() Directly return NULL or 'next' instead of breaking out of the loop. Signed-off-by: David Laight [ Split original patch into two independent parts - Linus ] Link: https://lore.kernel.org/lkml/7c8828aec72e42eeb841ca0ee3397e9a@AcuMS.aculab.com/ Signed-off-by: Linus Torvalds --- kernel/locking/osq_lock.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) diff --git a/kernel/locking/osq_lock.c b/kernel/locking/osq_lock.c index 15955ce35c53..75a6f6133866 100644 --- a/kernel/locking/osq_lock.c +++ b/kernel/locking/osq_lock.c @@ -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)