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| author | Christian Borntraeger <borntraeger@de.ibm.com> | 2015-09-11 16:09:56 +0200 |
|---|---|---|
| committer | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2015-10-14 14:32:00 +0200 |
| commit | e0af21c56ddd592b33f74f986a2cb4478b10786e (patch) | |
| tree | c5dd2779855656d9fda7eb7d1b90218b2a3f4599 /arch | |
| parent | s390/dasd: mark DASD devices as non rotational (diff) | |
| download | linux-e0af21c56ddd592b33f74f986a2cb4478b10786e.tar.xz linux-e0af21c56ddd592b33f74f986a2cb4478b10786e.zip | |
s390/spinlock: use correct barriers
_raw_write_lock_wait first sets the high order bit to indicate a
pending writer and then waits for the reader to drop to zero.
smp_rmb by definition only orders reads against reads. Let's use
a full smp_mb instead. As right now smp_rmb is implemented
as full serialization, this needs no stable backport, but this
patch will be necessary if we reimplement smp_rmb.
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/s390/lib/spinlock.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/s390/lib/spinlock.c b/arch/s390/lib/spinlock.c index d6c9991f7797..427aa44b3505 100644 --- a/arch/s390/lib/spinlock.c +++ b/arch/s390/lib/spinlock.c @@ -197,7 +197,7 @@ void _raw_write_lock_wait(arch_rwlock_t *rw, unsigned int prev) } old = ACCESS_ONCE(rw->lock); owner = ACCESS_ONCE(rw->owner); - smp_rmb(); + smp_mb(); if ((int) old >= 0) { prev = __RAW_LOCK(&rw->lock, 0x80000000, __RAW_OP_OR); old = prev; @@ -231,7 +231,7 @@ void _raw_write_lock_wait(arch_rwlock_t *rw) _raw_compare_and_swap(&rw->lock, old, old | 0x80000000)) prev = old; else - smp_rmb(); + smp_mb(); if ((old & 0x7fffffff) == 0 && (int) prev >= 0) break; if (MACHINE_HAS_CAD) |