Commit f878b657 authored by Trond Myklebust's avatar Trond Myklebust
Browse files

SUNRPC: Get rid of the xs_error_report socket callback 



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: default avatarChris Perl <chris.perl@gmail.com>
Signed-off-by: default avatarTrond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@vger.kernel.org
Tested-by: default avatarChris Perl <chris.perl@gmail.com>
parent 4bc1e68e

net/sunrpc/xprtsock.c

+0 −25
Original line number Diff line number Diff line
@@ -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)
@@ -1546,25 +1543,6 @@ 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;
@@ -1864,7 +1842,6 @@ 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);
@@ -1989,7 +1966,6 @@ 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;
@@ -2102,7 +2078,6 @@ 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 */

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