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Commit 9b674e82 authored by Allan Stephens's avatar Allan Stephens Committed by David S. Miller
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[TIPC]: Cosmetic cleanup of TIPC polling logic 



This patch eliminates an unnecessary poll-related routine
by merging it into TIPC's main polling routine, and updates
the comments associated with this code.

Signed-off-by: default avatarAllan Stephens <allan.stephens@windriver.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 67727184

net/tipc/socket.c

+36 −42
Original line number Diff line number Diff line
@@ -101,44 +101,6 @@ static void sock_unlock(struct tipc_sock* tsock) 
	spin_unlock_bh(tsock->p->lock);

}



/**

 * pollmask - determine the current set of poll() events for a socket

 * @sock: socket structure

 *

 * TIPC sets the returned events as follows:

 * a) POLLRDNORM and POLLIN are set if the socket's receive queue is non-empty

 *    or if a connection-oriented socket is does not have an active connection

 *    (i.e. a read operation will not block).

 * b) POLLOUT is set except when a socket's connection has been terminated

 *    (i.e. a write operation will not block).

 * c) POLLHUP is set when a socket's connection has been terminated.

 *

 * IMPORTANT: The fact that a read or write operation will not block does NOT

 * imply that the operation will succeed!

 *

 * Returns pollmask value

 */



static u32 pollmask(struct socket *sock)

{

	u32 mask;



	if ((skb_queue_len(&sock->sk->sk_receive_queue) != 0) ||

	    (sock->state == SS_UNCONNECTED) ||

	    (sock->state == SS_DISCONNECTING))

		mask = (POLLRDNORM | POLLIN);

	else

		mask = 0;



	if (sock->state == SS_DISCONNECTING)

		mask |= POLLHUP;

	else

		mask |= POLLOUT;



	return mask;

}





/**

 * advance_queue - discard first buffer in queue

 * @tsock: TIPC socket
@@ -390,15 +352,47 @@ static int get_name(struct socket *sock, struct sockaddr *uaddr, 
 * @sock: socket for which to calculate the poll bits

 * @wait: ???

 *

 * Returns the pollmask

 * Returns pollmask value

 *

 * COMMENTARY:

 * It appears that the usual socket locking mechanisms are not useful here

 * since the pollmask info is potentially out-of-date the moment this routine

 * exits.  TCP and other protocols seem to rely on higher level poll routines

 * to handle any preventable race conditions, so TIPC will do the same ...

 *

 * TIPC sets the returned events as follows:

 * a) POLLRDNORM and POLLIN are set if the socket's receive queue is non-empty

 *    or if a connection-oriented socket is does not have an active connection

 *    (i.e. a read operation will not block).

 * b) POLLOUT is set except when a socket's connection has been terminated

 *    (i.e. a write operation will not block).

 * c) POLLHUP is set when a socket's connection has been terminated.

 *

 * IMPORTANT: The fact that a read or write operation will not block does NOT

 * imply that the operation will succeed!

 */



static unsigned int poll(struct file *file, struct socket *sock,

			 poll_table *wait)

{

	poll_wait(file, sock->sk->sk_sleep, wait);

	/* NEED LOCK HERE? */

	return pollmask(sock);

	struct sock *sk = sock->sk;

	u32 mask;



	poll_wait(file, sk->sk_sleep, wait);



	if (!skb_queue_empty(&sk->sk_receive_queue) ||

	    (sock->state == SS_UNCONNECTED) ||

	    (sock->state == SS_DISCONNECTING))

		mask = (POLLRDNORM | POLLIN);

	else

		mask = 0;



	if (sock->state == SS_DISCONNECTING)

		mask |= POLLHUP;

	else

		mask |= POLLOUT;



	return mask;

}



/**