net: wrap sock->sk_cgrp_prioidx and ->sk_classid inside a struct

Introduce sock->sk_cgrp_data which is a struct sock_cgroup_data.
->sk_cgroup_prioidx and ->sk_classid are moved into it.  The struct
and its accessors are defined in cgroup-defs.h.  This is to prepare
for overloading the fields with a cgroup pointer.

This patch mostly performs equivalent conversions but the followings
are noteworthy.

* Equality test before updating classid is removed from
  sock_update_classid().  This shouldn't make any noticeable
  difference and a similar test will be implemented on the helper side
  later.

* sock_update_netprioidx() now takes struct sock_cgroup_data and can
  be moved to netprio_cgroup.h without causing include dependency
  loop.  Moved.

* The dummy version of sock_update_netprioidx() converted to a static
  inline function while at it.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

8 files changed, 19 insertions, 21 deletions

diff --git a/net/Kconfig b/net/Kconfig
index 127da94ae25e..11f8c22af34d 100644
--- a/net/Kconfig
+++ b/net/Kconfig
@@ -250,9 +250,14 @@ config XPS
 	depends on SMP
 	default y
 
+config SOCK_CGROUP_DATA
+	bool
+	default n
+
 config CGROUP_NET_PRIO
 	bool "Network priority cgroup"
 	depends on CGROUPS
+	select SOCK_CGROUP_DATA
 	---help---
 	  Cgroup subsystem for use in assigning processes to network priorities on
 	  a per-interface basis.
@@ -260,6 +265,7 @@ config CGROUP_NET_PRIO
 config CGROUP_NET_CLASSID
 	bool "Network classid cgroup"
 	depends on CGROUPS
+	select SOCK_CGROUP_DATA
 	---help---
 	  Cgroup subsystem for use as general purpose socket classid marker that is
 	  being used in cls_cgroup and for netfilter matching.
diff --git a/net/core/dev.c b/net/core/dev.c
index e5c395473eba..8f705fcedb94 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -2929,7 +2929,8 @@ static void skb_update_prio(struct sk_buff *skb)
 	struct netprio_map *map = rcu_dereference_bh(skb->dev->priomap);
 
 	if (!skb->priority && skb->sk && map) {
-		unsigned int prioidx = skb->sk->sk_cgrp_prioidx;
+		unsigned int prioidx =
+			sock_cgroup_prioidx(&skb->sk->sk_cgrp_data);
 
 		if (prioidx < map->priomap_len)
 			skb->priority = map->priomap[prioidx];
diff --git a/net/core/netclassid_cgroup.c b/net/core/netclassid_cgroup.c
index 2e4df84c34a1..e60ded46b3ac 100644
--- a/net/core/netclassid_cgroup.c
+++ b/net/core/netclassid_cgroup.c
@@ -62,8 +62,8 @@ static int update_classid_sock(const void *v, struct file *file, unsigned n)
 	struct socket *sock = sock_from_file(file, &err);
 
 	if (sock)
-		sock->sk->sk_classid = (u32)(unsigned long)v;
-
+		sock_cgroup_set_classid(&sock->sk->sk_cgrp_data,
+					(unsigned long)v);
 	return 0;
 }
 
diff --git a/net/core/netprio_cgroup.c b/net/core/netprio_cgroup.c
index 2b9159b7a28a..de42aa7f6c77 100644
--- a/net/core/netprio_cgroup.c
+++ b/net/core/netprio_cgroup.c
@@ -223,7 +223,8 @@ static int update_netprio(const void *v, struct file *file, unsigned n)
 	int err;
 	struct socket *sock = sock_from_file(file, &err);
 	if (sock)
-		sock->sk->sk_cgrp_prioidx = (u32)(unsigned long)v;
+		sock_cgroup_set_prioidx(&sock->sk->sk_cgrp_data,
+					(unsigned long)v);
 	return 0;
 }
 
diff --git a/net/core/scm.c b/net/core/scm.c
index 8a1741b14302..14596fb37172 100644
--- a/net/core/scm.c
+++ b/net/core/scm.c
@@ -289,8 +289,8 @@ void scm_detach_fds(struct msghdr *msg, struct scm_cookie *scm)
 		/* Bump the usage count and install the file. */
 		sock = sock_from_file(fp[i], &err);
 		if (sock) {
-			sock_update_netprioidx(sock->sk);
-			sock_update_classid(sock->sk);
+			sock_update_netprioidx(&sock->sk->sk_cgrp_data);
+			sock_update_classid(&sock->sk->sk_cgrp_data);
 		}
 		fd_install(new_fd, get_file(fp[i]));
 	}
diff --git a/net/core/sock.c b/net/core/sock.c
index 7965ef487375..947741dc43fa 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -1393,17 +1393,6 @@ static void sk_prot_free(struct proto *prot, struct sock *sk)
 	module_put(owner);
 }
 
-#if IS_ENABLED(CONFIG_CGROUP_NET_PRIO)
-void sock_update_netprioidx(struct sock *sk)
-{
-	if (in_interrupt())
-		return;
-
-	sk->sk_cgrp_prioidx = task_netprioidx(current);
-}
-EXPORT_SYMBOL_GPL(sock_update_netprioidx);
-#endif
-
 /**
  *	sk_alloc - All socket objects are allocated here
  *	@net: the applicable net namespace
@@ -1432,8 +1421,8 @@ struct sock *sk_alloc(struct net *net, int family, gfp_t priority,
 		sock_net_set(sk, net);
 		atomic_set(&sk->sk_wmem_alloc, 1);
 
-		sock_update_classid(sk);
-		sock_update_netprioidx(sk);
+		sock_update_classid(&sk->sk_cgrp_data);
+		sock_update_netprioidx(&sk->sk_cgrp_data);
 	}
 
 	return sk;
diff --git a/net/netfilter/nft_meta.c b/net/netfilter/nft_meta.c
index 9dfaf4d55ee0..1915cab7f32d 100644
--- a/net/netfilter/nft_meta.c
+++ b/net/netfilter/nft_meta.c
@@ -174,7 +174,7 @@ void nft_meta_get_eval(const struct nft_expr *expr,
 		sk = skb_to_full_sk(skb);
 		if (!sk || !sk_fullsock(sk))
 			goto err;
-		*dest = sk->sk_classid;
+		*dest = sock_cgroup_classid(&sk->sk_cgrp_data);
 		break;
 #endif
 	default:
diff --git a/net/netfilter/xt_cgroup.c b/net/netfilter/xt_cgroup.c
index a1d126f29463..54eaeb45ce99 100644
--- a/net/netfilter/xt_cgroup.c
+++ b/net/netfilter/xt_cgroup.c
@@ -42,7 +42,8 @@ cgroup_mt(const struct sk_buff *skb, struct xt_action_param *par)
 	if (skb->sk == NULL || !sk_fullsock(skb->sk))
 		return false;
 
-	return (info->id == skb->sk->sk_classid) ^ info->invert;
+	return (info->id == sock_cgroup_classid(&skb->sk->sk_cgrp_data)) ^
+		info->invert;
 }
 
 static struct xt_match cgroup_mt_reg __read_mostly = {