SUNRPC: Get rid of the xs_error_report socket callback

commit f878b657ce8e7d3673afe48110ec208a29e38c4a upstream.

Chris Perl reports that we're seeing races between the wakeup call in
xs_error_report and the connect attempts. Basically, Chris has shown
that in certain circumstances, the call to xs_error_report causes the
rpc_task that is responsible for reconnecting to wake up early, thus
triggering a disconnect and retry.

Since the sk->sk_error_report() calls in the socket layer are always
followed by a tcp_done() in the cases where we care about waking up
the rpc_tasks, just let the state_change callbacks take responsibility
for those wake ups.

Reported-by: Chris Perl <chris.perl@gmail.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Tested-by: Chris Perl <chris.perl@gmail.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c
index aada5df2f36068969f4bebd2ba16fab0a46da82e..65fe23b286f489803374421b9bbf48088574bc64 100644 (file)
--- a/net/sunrpc/xprtsock.c
+++ b/net/sunrpc/xprtsock.c
@@ -254,7 +254,6 @@ struct sock_xprt {
        void                    (*old_data_ready)(struct sock *, int);
        void                    (*old_state_change)(struct sock *);
        void                    (*old_write_space)(struct sock *);
-       void                    (*old_error_report)(struct sock *);
 };
 
 /*
@@ -781,7 +780,6 @@ static void xs_save_old_callbacks(struct sock_xprt *transport, struct sock *sk)
        transport->old_data_ready = sk->sk_data_ready;
        transport->old_state_change = sk->sk_state_change;
        transport->old_write_space = sk->sk_write_space;
-       transport->old_error_report = sk->sk_error_report;
 }
 
 static void xs_restore_old_callbacks(struct sock_xprt *transport, struct sock *sk)
@@ -789,7 +787,6 @@ static void xs_restore_old_callbacks(struct sock_xprt *transport, struct sock *s
        sk->sk_data_ready = transport->old_data_ready;
        sk->sk_state_change = transport->old_state_change;
        sk->sk_write_space = transport->old_write_space;
-       sk->sk_error_report = transport->old_error_report;
 }
 
 static void xs_reset_transport(struct sock_xprt *transport)
@@ -1558,25 +1555,6 @@ static void xs_tcp_state_change(struct sock *sk)
        read_unlock_bh(&sk->sk_callback_lock);
 }
 
-/**
- * xs_error_report - callback mainly for catching socket errors
- * @sk: socket
- */
-static void xs_error_report(struct sock *sk)
-{
-       struct rpc_xprt *xprt;
-
-       read_lock_bh(&sk->sk_callback_lock);
-       if (!(xprt = xprt_from_sock(sk)))
-               goto out;
-       dprintk("RPC:       %s client %p...\n"
-                       "RPC:       error %d\n",
-                       __func__, xprt, sk->sk_err);
-       xprt_wake_pending_tasks(xprt, -EAGAIN);
-out:
-       read_unlock_bh(&sk->sk_callback_lock);
-}
-
 static void xs_write_space(struct sock *sk)
 {
        struct socket *sock;
@@ -1876,7 +1854,6 @@ static int xs_local_finish_connecting(struct rpc_xprt *xprt,
                sk->sk_user_data = xprt;
                sk->sk_data_ready = xs_local_data_ready;
                sk->sk_write_space = xs_udp_write_space;
-               sk->sk_error_report = xs_error_report;
                sk->sk_allocation = GFP_ATOMIC;
 
                xprt_clear_connected(xprt);
@@ -1965,7 +1942,6 @@ static void xs_udp_finish_connecting(struct rpc_xprt *xprt, struct socket *sock)
                sk->sk_user_data = xprt;
                sk->sk_data_ready = xs_udp_data_ready;
                sk->sk_write_space = xs_udp_write_space;
-               sk->sk_error_report = xs_error_report;
                sk->sk_no_check = UDP_CSUM_NORCV;
                sk->sk_allocation = GFP_ATOMIC;
 
@@ -2079,7 +2055,6 @@ static int xs_tcp_finish_connecting(struct rpc_xprt *xprt, struct socket *sock)
                sk->sk_data_ready = xs_tcp_data_ready;
                sk->sk_state_change = xs_tcp_state_change;
                sk->sk_write_space = xs_tcp_write_space;
-               sk->sk_error_report = xs_error_report;
                sk->sk_allocation = GFP_ATOMIC;
 
                /* socket options */