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-rw-r--r--arch/s390/lib/spinlock.c14
1 files changed, 9 insertions, 5 deletions
diff --git a/arch/s390/lib/spinlock.c b/arch/s390/lib/spinlock.c
index c717f4a4c63e..01f29bb9c71b 100644
--- a/arch/s390/lib/spinlock.c
+++ b/arch/s390/lib/spinlock.c
@@ -149,9 +149,10 @@ EXPORT_SYMBOL(_raw_read_trylock_retry);
void _raw_write_lock_wait(arch_rwlock_t *rw)
{
- unsigned int owner, old;
+ unsigned int owner, old, prev;
int count = spin_retry;
+ prev = 0x80000000;
owner = 0;
while (1) {
if (count-- <= 0) {
@@ -161,10 +162,13 @@ void _raw_write_lock_wait(arch_rwlock_t *rw)
}
old = ACCESS_ONCE(rw->lock);
owner = ACCESS_ONCE(rw->owner);
- if (old)
- continue;
- if (_raw_compare_and_swap(&rw->lock, 0, 0x80000000))
- return;
+ if ((int) old >= 0 &&
+ _raw_compare_and_swap(&rw->lock, old, old | 0x80000000))
+ prev = old;
+ else
+ smp_rmb();
+ if ((old & 0x7fffffff) == 0 && (int) prev >= 0)
+ break;
}
}
EXPORT_SYMBOL(_raw_write_lock_wait);
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