net: poll/select low latency socket support

[~andy/linux] / net / socket.c

diff --git a/net/socket.c b/net/socket.c
index 3eec3f76b49c5a8b9035430463231fa7a72a660c..4da14cbd49b6486d08ec840e714b9f583835b685 100644 (file)
--- a/net/socket.c
+++ b/net/socket.c
@@ -107,6 +107,7 @@
 #include <net/ll_poll.h>
 
 #ifdef CONFIG_NET_LL_RX_POLL
+unsigned int sysctl_net_ll_read __read_mostly;
 unsigned int sysctl_net_ll_poll __read_mostly;
 #endif
 
@@ -1147,13 +1148,24 @@ EXPORT_SYMBOL(sock_create_lite);
 /* No kernel lock held - perfect */
 static unsigned int sock_poll(struct file *file, poll_table *wait)
 {
+       unsigned int ll_flag = 0;
        struct socket *sock;
 
        /*
         *      We can't return errors to poll, so it's either yes or no.
         */
        sock = file->private_data;
-       return sock->ops->poll(file, sock, wait);
+
+       if (sk_valid_ll(sock->sk)) {
+               /* this socket can poll_ll so tell the system call */
+               ll_flag = POLL_LL;
+
+               /* once, only if requested by syscall */
+               if (wait && (wait->_key & POLL_LL))
+                       sk_poll_ll(sock->sk, 1);
+       }
+
+       return ll_flag | sock->ops->poll(file, sock, wait);
 }
 
 static int sock_mmap(struct file *file, struct vm_area_struct *vma)