RDS: Use spinlock to protect 64b value update on 32b archs
We have a 64bit value that needs to be set atomically.
This is easy and quick on all 64bit archs, and can also be done
on x86/32 with set_64bit() (uses cmpxchg8b). However other
32b archs don't have this.
I actually changed this to the current state in preparation for
mainline because the old way (using a spinlock on 32b) resulted in
unsightly #ifdefs in the code. But obviously, being correct takes
precedence.
Signed-off-by: Andy Grover <andy.grover@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/rds/iw_cm.c b/net/rds/iw_cm.c
index 0ffaa3e..a416b0d 100644
--- a/net/rds/iw_cm.c
+++ b/net/rds/iw_cm.c
@@ -659,7 +659,11 @@
/* Clear the ACK state */
clear_bit(IB_ACK_IN_FLIGHT, &ic->i_ack_flags);
- rds_iw_set_64bit(&ic->i_ack_next, 0);
+#ifdef KERNEL_HAS_ATOMIC64
+ atomic64_set(&ic->i_ack_next, 0);
+#else
+ ic->i_ack_next = 0;
+#endif
ic->i_ack_recv = 0;
/* Clear flow control state */
@@ -693,6 +697,9 @@
INIT_LIST_HEAD(&ic->iw_node);
mutex_init(&ic->i_recv_mutex);
+#ifndef KERNEL_HAS_ATOMIC64
+ spin_lock_init(&ic->i_ack_lock);
+#endif
/*
* rds_iw_conn_shutdown() waits for these to be emptied so they