From: Florian Westphal <fw@strlen.de>
Date: Mon, 9 Jan 2017 13:20:49 +0000 (+0100)
Subject: xfrm: state: simplify rcu_read_unlock handling in two spots
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=75cda62d9ca2cd3fab0412d438fcd1bfa0580b3d;p=GitHub%2Fmoto-9609%2Fandroid_kernel_motorola_exynos9610.git

xfrm: state: simplify rcu_read_unlock handling in two spots

Instead of:
  if (foo) {
      unlock();
      return bar();
   }
   unlock();
do:
   unlock();
   if (foo)
       return bar();

This is ok because rcu protected structure is only dereferenced before
the conditional.

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

diff --git a/net/xfrm/xfrm_state.c b/net/xfrm/xfrm_state.c
index b5dad899fb0e..a62097e640b5 100644
--- a/net/xfrm/xfrm_state.c
+++ b/net/xfrm/xfrm_state.c
@@ -231,17 +231,18 @@ retry:
 		return NULL;
 	typemap = afinfo->type_map;
 
-	type = typemap[proto];
+	type = READ_ONCE(typemap[proto]);
 	if (unlikely(type && !try_module_get(type->owner)))
 		type = NULL;
+
+	rcu_read_unlock();
+
 	if (!type && !modload_attempted) {
-		rcu_read_unlock();
 		request_module("xfrm-type-%d-%d", family, proto);
 		modload_attempted = 1;
 		goto retry;
 	}
 
-	rcu_read_unlock();
 	return type;
 }
 
@@ -327,17 +328,17 @@ retry:
 	if (unlikely(afinfo == NULL))
 		return NULL;
 
-	mode = afinfo->mode_map[encap];
+	mode = READ_ONCE(afinfo->mode_map[encap]);
 	if (unlikely(mode && !try_module_get(mode->owner)))
 		mode = NULL;
+
+	rcu_read_unlock();
 	if (!mode && !modload_attempted) {
-		rcu_read_unlock();
 		request_module("xfrm-mode-%d-%d", family, encap);
 		modload_attempted = 1;
 		goto retry;
 	}
 
-	rcu_read_unlock();
 	return mode;
 }