diff options
| -rw-r--r-- | arch/s390/lib/spinlock.c | 14 |
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); |