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authorJiri Kosina <[email protected]>2020-04-01 12:26:12 +0200
committerJiri Kosina <[email protected]>2020-04-01 12:26:12 +0200
commitc9f289701540baeef9ac7c9977d67a7259f404db (patch)
treeac3c29d41da02ac735c9a12da78905842fbccd2f /kernel/locking/osq_lock.c
parent0aac6f9aaae5fba08963651d2ce49930145e118f (diff)
parent910a7e89cec65efad254c947ce2bf8bf5b370962 (diff)
Merge branch 'for-5.7/appleir' into for-linus
- small code cleanups in hid-appleir from Lucas Tanure
Diffstat (limited to 'kernel/locking/osq_lock.c')
-rw-r--r--kernel/locking/osq_lock.c23
1 files changed, 10 insertions, 13 deletions
diff --git a/kernel/locking/osq_lock.c b/kernel/locking/osq_lock.c
index 6ef600aa0f47..1f7734949ac8 100644
--- a/kernel/locking/osq_lock.c
+++ b/kernel/locking/osq_lock.c
@@ -134,20 +134,17 @@ bool osq_lock(struct optimistic_spin_queue *lock)
* cmpxchg in an attempt to undo our queueing.
*/
- while (!READ_ONCE(node->locked)) {
- /*
- * If we need to reschedule bail... so we can block.
- * Use vcpu_is_preempted() to avoid waiting for a preempted
- * lock holder:
- */
- if (need_resched() || vcpu_is_preempted(node_cpu(node->prev)))
- goto unqueue;
-
- cpu_relax();
- }
- return true;
+ /*
+ * Wait to acquire the lock or cancelation. Note that need_resched()
+ * will come with an IPI, which will wake smp_cond_load_relaxed() if it
+ * is implemented with a monitor-wait. vcpu_is_preempted() relies on
+ * polling, be careful.
+ */
+ if (smp_cond_load_relaxed(&node->locked, VAL || need_resched() ||
+ vcpu_is_preempted(node_cpu(node->prev))))
+ return true;
-unqueue:
+ /* unqueue */
/*
* Step - A -- stabilize @prev
*