SUNRPC: Fix memory barriers for req->rq_received
We need to ensure that all writes to the XDR buffers are done before
req->rq_received is visible to other processors.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c
index 9f77530..6e71d6a 100644
--- a/net/sunrpc/clnt.c
+++ b/net/sunrpc/clnt.c
@@ -1069,6 +1069,11 @@
return;
}
+ /*
+ * Ensure that we see all writes made by xprt_complete_rqst()
+ * before it changed req->rq_received.
+ */
+ smp_rmb();
req->rq_rcv_buf.len = req->rq_private_buf.len;
/* Check that the softirq receive buffer is valid */
diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c
index 940dba9..4dd5b3c 100644
--- a/net/sunrpc/xprt.c
+++ b/net/sunrpc/xprt.c
@@ -651,6 +651,8 @@
task->tk_rtt = (long)jiffies - req->rq_xtime;
list_del_init(&req->rq_list);
+ /* Ensure all writes are done before we update req->rq_received */
+ smp_wmb();
req->rq_received = req->rq_private_buf.len = copied;
rpc_wake_up_task(task);
}
@@ -727,7 +729,6 @@
dprintk("RPC: %4d xprt_transmit(%u)\n", task->tk_pid, req->rq_slen);
- smp_rmb();
if (!req->rq_received) {
if (list_empty(&req->rq_list)) {
spin_lock_bh(&xprt->transport_lock);