rpc: allow xprt_class->setup to return a preexisting xprt
This allows us to reuse the xprt associated with a server connection if
one has already been set up.
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
diff --git a/include/linux/sunrpc/xprt.h b/include/linux/sunrpc/xprt.h
index 89d10d2..bef0f53 100644
--- a/include/linux/sunrpc/xprt.h
+++ b/include/linux/sunrpc/xprt.h
@@ -321,6 +321,7 @@
#define XPRT_CLOSING (6)
#define XPRT_CONNECTION_ABORT (7)
#define XPRT_CONNECTION_CLOSE (8)
+#define XPRT_INITIALIZED (9)
static inline void xprt_set_connected(struct rpc_xprt *xprt)
{
diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c
index 749ad15..856274d 100644
--- a/net/sunrpc/xprt.c
+++ b/net/sunrpc/xprt.c
@@ -1102,6 +1102,9 @@
-PTR_ERR(xprt));
return xprt;
}
+ if (test_and_set_bit(XPRT_INITIALIZED, &xprt->state))
+ /* ->setup returned a pre-initialized xprt: */
+ return xprt;
spin_lock_init(&xprt->transport_lock);
spin_lock_init(&xprt->reserve_lock);
diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c
index 0ef4dd4..ee091c8 100644
--- a/net/sunrpc/xprtsock.c
+++ b/net/sunrpc/xprtsock.c
@@ -2359,6 +2359,15 @@
struct svc_sock *bc_sock;
struct rpc_xprt *ret;
+ if (args->bc_xprt->xpt_bc_xprt) {
+ /*
+ * This server connection already has a backchannel
+ * export; we can't create a new one, as we wouldn't be
+ * able to match replies based on xid any more. So,
+ * reuse the already-existing one:
+ */
+ return args->bc_xprt->xpt_bc_xprt;
+ }
xprt = xs_setup_xprt(args, xprt_tcp_slot_table_entries);
if (IS_ERR(xprt))
return xprt;
@@ -2397,15 +2406,6 @@
xprt->address_strings[RPC_DISPLAY_PROTO]);
/*
- * The backchannel uses the same socket connection as the
- * forechannel
- */
- if (args->bc_xprt->xpt_bc_xprt) {
- /* XXX: actually, want to catch this case... */
- ret = ERR_PTR(-EINVAL);
- goto out_err;
- }
- /*
* Once we've associated a backchannel xprt with a connection,
* we want to keep it around as long as long as the connection
* lasts, in case we need to start using it for a backchannel