To clear out old state, the UDP connect workers unconditionally invoke
xs_close() before proceeding with a new connect. Nowadays this causes
a spurious wake-up of the task waiting for the connect to complete.
This is a little racey, but usually harmless. The waiting task
immediately retries the connect via a call_bind/call_connect sequence,
which usually finds the transport already in the connected state
because the connect worker has finished in the background.
To avoid a spurious wake-up, factor the xs_close() logic that resets
the underlying socket into a helper, and have the UDP connect workers
call that helper instead of xs_close().
Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
---
net/sunrpc/xprtsock.c | 44 ++++++++++++++++++++++++++------------------
1 files changed, 26 insertions(+), 18 deletions(-)
diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c
index 0a50361..883dc2f 100644
--- a/net/sunrpc/xprtsock.c
+++ b/net/sunrpc/xprtsock.c
@@ -760,23 +760,13 @@ static void xs_restore_old_callbacks(struct sock_xprt *transport, struct sock *s
sk->sk_error_report = transport->old_error_report;
}
-/**
- * xs_close - close a socket
- * @xprt: transport
- *
- * This is used when all requests are complete; ie, no DRC state remains
- * on the server we want to save.
- */
-static void xs_close(struct rpc_xprt *xprt)
+static void xs_reset_transport(struct sock_xprt *transport)
{
- struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
struct socket *sock = transport->sock;
struct sock *sk = transport->inet;
- if (!sk)
- goto clear_close_wait;
-
- dprintk("RPC: xs_close xprt %p\n", xprt);
+ if (sk == NULL)
+ return;
write_lock_bh(&sk->sk_callback_lock);
transport->inet = NULL;
@@ -790,7 +780,23 @@ static void xs_close(struct rpc_xprt *xprt)
sk->sk_no_check = 0;
sock_release(sock);
-clear_close_wait:
+}
+
+/**
+ * xs_close - close a socket
+ * @xprt: transport
+ *
+ * This is used when all requests are complete; ie, no DRC state remains
+ * on the server we want to save.
+ */
+static void xs_close(struct rpc_xprt *xprt)
+{
+ struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
+
+ dprintk("RPC: xs_close xprt %p\n", xprt);
+
+ xs_reset_transport(transport);
+
smp_mb__before_clear_bit();
clear_bit(XPRT_CLOSE_WAIT, &xprt->state);
clear_bit(XPRT_CLOSING, &xprt->state);
@@ -1530,9 +1536,10 @@ static void xs_udp_connect_worker4(struct work_struct *work)
goto out;
/* Start by resetting any existing state */
- xs_close(xprt);
+ xs_reset_transport(transport);
- if ((err = sock_create_kern(PF_INET, SOCK_DGRAM, IPPROTO_UDP, &sock)) < 0) {
+ err = sock_create_kern(PF_INET, SOCK_DGRAM, IPPROTO_UDP, &sock);
+ if (err < 0) {
dprintk("RPC: can't create UDP transport socket (%d).\n", -err);
goto out;
}
@@ -1571,9 +1578,10 @@ static void xs_udp_connect_worker6(struct work_struct *work)
goto out;
/* Start by resetting any existing state */
- xs_close(xprt);
+ xs_reset_transport(transport);
- if ((err = sock_create_kern(PF_INET6, SOCK_DGRAM, IPPROTO_UDP, &sock)) < 0) {
+ err = sock_create_kern(PF_INET6, SOCK_DGRAM, IPPROTO_UDP, &sock);
+ if (err < 0) {
dprintk("RPC: can't create UDP transport socket (%d).\n", -err);
goto out;
}
--
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