netdev - [PATCH 04/15] xfrm: avoid rcu sparse warning

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Date:   Wed, 1 Feb 2017 09:17:46 +0100
From:   Steffen Klassert <steffen.klassert@...unet.com>
To:     David Miller <davem@...emloft.net>
CC:     Herbert Xu <herbert@...dor.apana.org.au>,
        Steffen Klassert <steffen.klassert@...unet.com>,
        <netdev@...r.kernel.org>
Subject: [PATCH 04/15] xfrm: avoid rcu sparse warning

From: Florian Westphal <fw@...len.de>

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@...len.de>
Signed-off-by: Steffen Klassert <steffen.klassert@...unet.com>
---
 net/xfrm/xfrm_state.c | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

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 @@ int xfrm_unregister_km(struct xfrm_mgr *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 @@ int xfrm_state_register_afinfo(struct xfrm_state_afinfo *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);
-- 
1.9.1