powerpc/eeh: atomic_dec_if_positive() to update passthru count
No need to have two atomic opertions (update and fetch/check) when
decreasing PE's number of passed devices as one atomic operation
is enough.
Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
diff --git a/arch/powerpc/kernel/eeh.c b/arch/powerpc/kernel/eeh.c
index 00ba5de..893978c 100644
--- a/arch/powerpc/kernel/eeh.c
+++ b/arch/powerpc/kernel/eeh.c
@@ -1412,8 +1412,7 @@
goto out;
/* Decrease PE's pass through count */
- atomic_dec(&edev->pe->pass_dev_cnt);
- WARN_ON(atomic_read(&edev->pe->pass_dev_cnt) < 0);
+ WARN_ON(atomic_dec_if_positive(&edev->pe->pass_dev_cnt) < 0);
eeh_pe_change_owner(edev->pe);
out:
mutex_unlock(&eeh_dev_mutex);