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locking/osq_lock: Clarify osq_wait_next()

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

Signed-off-by: David 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: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
David Laight 2023-12-29 20:56:03 +00:00 committed by Linus Torvalds
parent 563adbfc35
commit b106bcf0f9
1 changed files with 4 additions and 5 deletions
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9
kernel/locking/osq_lock.c
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@ -55,7 +55,6 @@ osq_wait_next(struct optimistic_spin_queue *lock,
struct optimistic_spin_node *node, struct optimistic_spin_node *node,
int old_cpu) int old_cpu)
{ {
struct optimistic_spin_node *next = NULL;
int curr = encode_cpu(smp_processor_id()); int curr = encode_cpu(smp_processor_id());
for (;;) { for (;;) {
@ -66,7 +65,7 @@ osq_wait_next(struct optimistic_spin_queue *lock,
* will now observe @lock and will complete its * will now observe @lock and will complete its
* unlock()/unqueue(). * 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. * wait for a new @node->next from its Step-C.
*/ */
if (node->next) { if (node->next) {
struct optimistic_spin_node *next;
next = xchg(&node->next, NULL); next = xchg(&node->next, NULL);
if (next) if (next)
break; return next;
} }
cpu_relax(); cpu_relax();
} }
return next;
} }
bool osq_lock(struct optimistic_spin_queue *lock) bool osq_lock(struct optimistic_spin_queue *lock)