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>

4 files changed, 57 insertions, 17 deletions

diff --git a/include/linux/cgroup-defs.h b/include/linux/cgroup-defs.h
index 504d8591b6d3..ed128fed0335 100644
--- a/include/linux/cgroup-defs.h
+++ b/include/linux/cgroup-defs.h
@@ -542,4 +542,40 @@ static inline void cgroup_threadgroup_change_end(struct task_struct *tsk) {}
 
 #endif	/* CONFIG_CGROUPS */
 
+#ifdef CONFIG_SOCK_CGROUP_DATA
+
+struct sock_cgroup_data {
+	u16	prioidx;
+	u32	classid;
+};
+
+static inline u16 sock_cgroup_prioidx(struct sock_cgroup_data *skcd)
+{
+	return skcd->prioidx;
+}
+
+static inline u32 sock_cgroup_classid(struct sock_cgroup_data *skcd)
+{
+	return skcd->classid;
+}
+
+static inline void sock_cgroup_set_prioidx(struct sock_cgroup_data *skcd,
+					   u16 prioidx)
+{
+	skcd->prioidx = prioidx;
+}
+
+static inline void sock_cgroup_set_classid(struct sock_cgroup_data *skcd,
+					   u32 classid)
+{
+	skcd->classid = classid;
+}
+
+#else	/* CONFIG_SOCK_CGROUP_DATA */
+
+struct sock_cgroup_data {
+};
+
+#endif	/* CONFIG_SOCK_CGROUP_DATA */
+
 #endif	/* _LINUX_CGROUP_DEFS_H */
diff --git a/include/net/cls_cgroup.h b/include/net/cls_cgroup.h
index ccd6d8bffa4d..c0a92e2c286d 100644
--- a/include/net/cls_cgroup.h
+++ b/include/net/cls_cgroup.h
@@ -41,13 +41,12 @@ static inline u32 task_cls_classid(struct task_struct *p)
 	return classid;
 }
 
-static inline void sock_update_classid(struct sock *sk)
+static inline void sock_update_classid(struct sock_cgroup_data *skcd)
 {
 	u32 classid;
 
 	classid = task_cls_classid(current);
-	if (classid != sk->sk_classid)
-		sk->sk_classid = classid;
+	sock_cgroup_set_classid(skcd, classid);
 }
 
 static inline u32 task_get_classid(const struct sk_buff *skb)
@@ -64,17 +63,17 @@ static inline u32 task_get_classid(const struct sk_buff *skb)
 	 * softirqs always disables bh.
 	 */
 	if (in_serving_softirq()) {
-		/* If there is an sk_classid we'll use that. */
+		/* If there is an sock_cgroup_classid we'll use that. */
 		if (!skb->sk)
 			return 0;
 
-		classid = skb->sk->sk_classid;
+		classid = sock_cgroup_classid(&skb->sk->sk_cgrp_data);
 	}
 
 	return classid;
 }
 #else /* !CONFIG_CGROUP_NET_CLASSID */
-static inline void sock_update_classid(struct sock *sk)
+static inline void sock_update_classid(struct sock_cgroup_data *skcd)
 {
 }
 
diff --git a/include/net/netprio_cgroup.h b/include/net/netprio_cgroup.h
index f2a9597ff53c..604190596cde 100644
--- a/include/net/netprio_cgroup.h
+++ b/include/net/netprio_cgroup.h
@@ -25,8 +25,6 @@ struct netprio_map {
 	u32 priomap[];
 };
 
-void sock_update_netprioidx(struct sock *sk);
-
 static inline u32 task_netprioidx(struct task_struct *p)
 {
 	struct cgroup_subsys_state *css;
@@ -38,13 +36,25 @@ static inline u32 task_netprioidx(struct task_struct *p)
 	rcu_read_unlock();
 	return idx;
 }
+
+static inline void sock_update_netprioidx(struct sock_cgroup_data *skcd)
+{
+	if (in_interrupt())
+		return;
+
+	sock_cgroup_set_prioidx(skcd, task_netprioidx(current));
+}
+
 #else /* !CONFIG_CGROUP_NET_PRIO */
+
 static inline u32 task_netprioidx(struct task_struct *p)
 {
 	return 0;
 }
 
-#define sock_update_netprioidx(sk)
+static inline void sock_update_netprioidx(struct sock_cgroup_data *skcd)
+{
+}
 
 #endif /* CONFIG_CGROUP_NET_PRIO */
 #endif  /* _NET_CLS_CGROUP_H */
diff --git a/include/net/sock.h b/include/net/sock.h
index a95bcf7d6efa..0ca22b014de1 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -59,6 +59,7 @@
 #include <linux/static_key.h>
 #include <linux/sched.h>
 #include <linux/wait.h>
+#include <linux/cgroup-defs.h>
 
 #include <linux/filter.h>
 #include <linux/rculist_nulls.h>
@@ -308,8 +309,7 @@ struct cg_proto;
   *	@sk_send_head: front of stuff to transmit
   *	@sk_security: used by security modules
   *	@sk_mark: generic packet mark
-  *	@sk_cgrp_prioidx: socket group's priority map index
-  *	@sk_classid: this socket's cgroup classid
+  *	@sk_cgrp_data: cgroup data for this cgroup
   *	@sk_cgrp: this socket's cgroup-specific proto data
   *	@sk_write_pending: a write to stream socket waits to start
   *	@sk_state_change: callback to indicate change in the state of the sock
@@ -443,12 +443,7 @@ struct sock {
 #ifdef CONFIG_SECURITY
 	void			*sk_security;
 #endif
-#if IS_ENABLED(CONFIG_CGROUP_NET_PRIO)
-	u16			sk_cgrp_prioidx;
-#endif
-#ifdef CONFIG_CGROUP_NET_CLASSID
-	u32			sk_classid;
-#endif
+	struct sock_cgroup_data	sk_cgrp_data;
 	struct cg_proto		*sk_cgrp;
 	void			(*sk_state_change)(struct sock *sk);
 	void			(*sk_data_ready)(struct sock *sk);