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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: Allan Stephens <allan.stephens@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Allan Stephens 2008-03-26 16:48:21 -07:00 committed by David S. Miller
parent 67727184f2
commit 9b674e82b7
1 changed files with 36 additions and 42 deletions
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78
net/tipc/socket.c
View File

@ -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* since the pollmask info is potentially out-of-date the moment this routine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;
}
/**