SK_WAIT_DATA(9) Linux Networking SK_WAIT_DATA(9)NAME
sk_wait_data - wait for data to arrive at sk_receive_queue
SYNOPSIS
int sk_wait_data(struct sock * sk, long * timeo);
ARGUMENTS
sk
sock to wait on
timeo
for how long
DESCRIPTION
Now socket state including sk->sk_err is changed only under lock, hence we may omit checks after joining wait queue. We check receive queue
before schedule only as optimization; it is very likely that release_sock added new data.
COPYRIGHT Kernel Hackers Manual 2.6. July 2010 SK_WAIT_DATA(9)
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__SKB_RECV_DATAGRAM(9) Linux Networking __SKB_RECV_DATAGRAM(9)NAME
__skb_recv_datagram - Receive a datagram skbuff
SYNOPSIS
struct sk_buff * __skb_recv_datagram(struct sock * sk, unsigned flags, int * peeked, int * err);
ARGUMENTS
sk
socket
flags
MSG_ flags
peeked
returns non-zero if this packet has been seen before
err
error code returned
DESCRIPTION
Get a datagram skbuff, understands the peeking, nonblocking wakeups and possible races. This replaces identical code in packet, raw and
udp, as well as the IPX AX.25 and Appletalk. It also finally fixes the long standing peek and read race for datagram sockets. If you alter
this routine remember it must be re-entrant.
This function will lock the socket if a skb is returned, so the caller needs to unlock the socket in that case (usually by calling
skb_free_datagram)
* It does not lock socket since today. This function is * free of race conditions. This measure should/can improve * significantly datagram
socket latencies at high loads, * when data copying to user space takes lots of time. * (BTW I've just killed the last cli in
IP/IPv6/core/netlink/packet * 8) Great win.) * --ANK (980729)
The order of the tests when we find no data waiting are specified quite explicitly by POSIX 1003.1g, don't change them without having the
standard around please.
COPYRIGHT Kernel Hackers Manual 2.6. July 2010 __SKB_RECV_DATAGRAM(9)