netfilter: x_tables: simplify IS_ERR_OR_NULL to NULL test

Since commit 7926dbfa4bc1 ("netfilter: don't use
mutex_lock_interruptible()"), the function xt_find_table_lock can only
return NULL on an error.  Simplify the call sites and update the
comment before the function.

The semantic patch that change the code is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@@
expression t,e;
@@

t = \(xt_find_table_lock(...)\|
      try_then_request_module(xt_find_table_lock(...),...)\)
... when != t=e
- ! IS_ERR_OR_NULL(t)
+ t

@@
expression t,e;
@@

t = \(xt_find_table_lock(...)\|
      try_then_request_module(xt_find_table_lock(...),...)\)
... when != t=e
- IS_ERR_OR_NULL(t)
+ !t

@@
expression t,e,e1;
@@

t = \(xt_find_table_lock(...)\|
      try_then_request_module(xt_find_table_lock(...),...)\)
... when != t=e
?- t ? PTR_ERR(t) : e1
+ e1
... when any

// </smpl>

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

1 files changed, 10 insertions, 10 deletions

diff --git a/net/ipv6/netfilter/ip6_tables.c b/net/ipv6/netfilter/ip6_tables.c
index 7eac01d5d621..6ff42b8301cc 100644
--- a/net/ipv6/netfilter/ip6_tables.c
+++ b/net/ipv6/netfilter/ip6_tables.c
@@ -1003,7 +1003,7 @@ static int get_info(struct net *net, void __user *user,
 #endif
 	t = try_then_request_module(xt_find_table_lock(net, AF_INET6, name),
 				    "ip6table_%s", name);
-	if (!IS_ERR_OR_NULL(t)) {
+	if (t) {
 		struct ip6t_getinfo info;
 		const struct xt_table_info *private = t->private;
 #ifdef CONFIG_COMPAT
@@ -1033,7 +1033,7 @@ static int get_info(struct net *net, void __user *user,
 		xt_table_unlock(t);
 		module_put(t->me);
 	} else
-		ret = t ? PTR_ERR(t) : -ENOENT;
+		ret = -ENOENT;
 #ifdef CONFIG_COMPAT
 	if (compat)
 		xt_compat_unlock(AF_INET6);
@@ -1059,7 +1059,7 @@ get_entries(struct net *net, struct ip6t_get_entries __user *uptr,
 	get.name[sizeof(get.name) - 1] = '\0';
 
 	t = xt_find_table_lock(net, AF_INET6, get.name);
-	if (!IS_ERR_OR_NULL(t)) {
+	if (t) {
 		struct xt_table_info *private = t->private;
 		if (get.size == private->size)
 			ret = copy_entries_to_user(private->size,
@@ -1070,7 +1070,7 @@ get_entries(struct net *net, struct ip6t_get_entries __user *uptr,
 		module_put(t->me);
 		xt_table_unlock(t);
 	} else
-		ret = t ? PTR_ERR(t) : -ENOENT;
+		ret = -ENOENT;
 
 	return ret;
 }
@@ -1095,8 +1095,8 @@ __do_replace(struct net *net, const char *name, unsigned int valid_hooks,
 
 	t = try_then_request_module(xt_find_table_lock(net, AF_INET6, name),
 				    "ip6table_%s", name);
-	if (IS_ERR_OR_NULL(t)) {
-		ret = t ? PTR_ERR(t) : -ENOENT;
+	if (!t) {
+		ret = -ENOENT;
 		goto free_newinfo_counters_untrans;
 	}
 
@@ -1210,8 +1210,8 @@ do_add_counters(struct net *net, const void __user *user, unsigned int len,
 	if (IS_ERR(paddc))
 		return PTR_ERR(paddc);
 	t = xt_find_table_lock(net, AF_INET6, tmp.name);
-	if (IS_ERR_OR_NULL(t)) {
-		ret = t ? PTR_ERR(t) : -ENOENT;
+	if (!t) {
+		ret = -ENOENT;
 		goto free;
 	}
 
@@ -1647,7 +1647,7 @@ compat_get_entries(struct net *net, struct compat_ip6t_get_entries __user *uptr,
 
 	xt_compat_lock(AF_INET6);
 	t = xt_find_table_lock(net, AF_INET6, get.name);
-	if (!IS_ERR_OR_NULL(t)) {
+	if (t) {
 		const struct xt_table_info *private = t->private;
 		struct xt_table_info info;
 		ret = compat_table_info(private, &info);
@@ -1661,7 +1661,7 @@ compat_get_entries(struct net *net, struct compat_ip6t_get_entries __user *uptr,
 		module_put(t->me);
 		xt_table_unlock(t);
 	} else
-		ret = t ? PTR_ERR(t) : -ENOENT;
+		ret = -ENOENT;
 
 	xt_compat_unlock(AF_INET6);
 	return ret;