tipc: avoid to unnecessary process switch under non-block mode
tipc: avoid to unnecessary process switch under non-block mode

When messages are received via tipc socket under non-block mode,
schedule_timeout() is called in tipc_wait_for_rcvmsg(), that is,
the process of receiving messages will be scheduled once although
timeout value passed to schedule_timeout() is 0. The same issue
exists in accept()/wait_for_accept(). To avoid this unnecessary
process switch, we only call schedule_timeout() if the timeout
value is non-zero.

Signed-off-by: Ying Xue <c1cbb87de349443b90fa63f6d2cc5403843bc133@windriver.com>
Reviewed-by: Erik Hugne <527d9b95423f3946c01de0ba884fdd8bb4a3759d@ericsson.com>
Reviewed-by: Jon Maloy <0e60c7c02f6d30eccc82572d2a89766b1b2a3d45@ericsson.com>
Signed-off-by: David S. Miller <fe08d3c717adf2ae63592e4c9aec6e3e404d8e3e@davemloft.net>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs