net: netprio_cgroup: rework update socket logic

Instead of updating the sk_cgrp_prioidx struct field on every send
this only updates the field when a task is moved via cgroup
infrastructure.

This allows sockets that may be used by a kernel worker thread
to be managed. For example in the iscsi case today a user can
put iscsid in a netprio cgroup and control traffic will be sent
with the correct sk_cgrp_prioidx value set but as soon as data
is sent the kernel worker thread isssues a send and sk_cgrp_prioidx
is updated with the kernel worker threads value which is the
default case.

It seems more correct to only update the field when the user
explicitly sets it via control group infrastructure. This allows
the users to manage sockets that may be used with other threads.

Signed-off-by: John Fastabend <john.r.fastabend@intel.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 3 deletions

diff --git a/net/socket.c b/net/socket.c
index 0452dca4cd24..dfe5b66c97e0 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -398,7 +398,7 @@ int sock_map_fd(struct socket *sock, int flags)
 }
 EXPORT_SYMBOL(sock_map_fd);
 
-static struct socket *sock_from_file(struct file *file, int *err)
+struct socket *sock_from_file(struct file *file, int *err)
 {
 	if (file->f_op == &socket_file_ops)
 		return file->private_data;	/* set in sock_map_fd */
@@ -406,6 +406,7 @@ static struct socket *sock_from_file(struct file *file, int *err)
 	*err = -ENOTSOCK;
 	return NULL;
 }
+EXPORT_SYMBOL(sock_from_file);
 
 /**
  *	sockfd_lookup - Go from a file number to its socket slot
@@ -554,8 +555,6 @@ static inline int __sock_sendmsg_nosec(struct kiocb *iocb, struct socket *sock,
 
 	sock_update_classid(sock->sk);
 
-	sock_update_netprioidx(sock->sk);
-
 	si->sock = sock;
 	si->scm = NULL;
 	si->msg = msg;