commit 423826a7b104724a16676a75d597a35d3bdb18b8
author Florian Westphal <fw@strlen.de> Mon Jan 09 14:20:46 2017 +0100
committer Steffen Klassert <steffen.klassert@secunet.com> Tue Jan 10 10:57:13 2017 +0100
tree 3b8b9f0e170d5bb26a3a15a8d144718b925834ed
parent 961a9c0a4a9783e47f8cb76134b2303c4872380b

xfrm: avoid rcu sparse warning

xfrm/xfrm_state.c:1973:21: error: incompatible types in comparison expression (different address spaces)

Harmless, but lets fix it to reduce the noise.

While at it, get rid of unneeded NULL check, its never hit:

net/ipv4/xfrm4_state.c: xfrm_state_register_afinfo(&xfrm4_state_afinfo);
net/ipv6/xfrm6_state.c: return xfrm_state_register_afinfo(&xfrm6_state_afinfo);
net/ipv6/xfrm6_state.c: xfrm_state_unregister_afinfo(&xfrm6_state_afinfo);

... are the only callsites.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

net/xfrm/xfrm_state.c

diff --git a/net/xfrm/xfrm_state.c b/net/xfrm/xfrm_state.c
index 6b3366f..57e9578 100644
--- a/net/xfrm/xfrm_state.c
+++ b/net/xfrm/xfrm_state.c
@@ -1932,10 +1932,10 @@ EXPORT_SYMBOL(xfrm_unregister_km);
 int xfrm_state_register_afinfo(struct xfrm_state_afinfo *afinfo)
 {
 	int err = 0;
-	if (unlikely(afinfo == NULL))
-		return -EINVAL;
-	if (unlikely(afinfo->family >= NPROTO))
+
+	if (WARN_ON(afinfo->family >= NPROTO))
 		return -EAFNOSUPPORT;
+
 	spin_lock_bh(&xfrm_state_afinfo_lock);
 	if (unlikely(xfrm_state_afinfo[afinfo->family] != NULL))
 		err = -EEXIST;
@@ -1948,14 +1948,14 @@ EXPORT_SYMBOL(xfrm_state_register_afinfo);
 
 int xfrm_state_unregister_afinfo(struct xfrm_state_afinfo *afinfo)
 {
-	int err = 0;
-	if (unlikely(afinfo == NULL))
-		return -EINVAL;
-	if (unlikely(afinfo->family >= NPROTO))
+	int err = 0, family = afinfo->family;
+
+	if (WARN_ON(family >= NPROTO))
 		return -EAFNOSUPPORT;
+
 	spin_lock_bh(&xfrm_state_afinfo_lock);
 	if (likely(xfrm_state_afinfo[afinfo->family] != NULL)) {
-		if (unlikely(xfrm_state_afinfo[afinfo->family] != afinfo))
+		if (rcu_access_pointer(xfrm_state_afinfo[family]) != afinfo)
 			err = -EINVAL;
 		else
 			RCU_INIT_POINTER(xfrm_state_afinfo[afinfo->family], NULL);