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netfilter: x_tables: simplify IS_ERR_OR_NULL to NULL test
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Since commit 7926dbf ("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>
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Julia Lawall authored and Pablo Neira Ayuso committed Nov 13, 2016
1 parent 7e416ad commit eb1a6bd
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Showing 4 changed files with 31 additions and 31 deletions.
20 changes: 10 additions & 10 deletions net/ipv4/netfilter/arp_tables.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -805,7 +805,7 @@ static int get_info(struct net *net, void __user *user,
#endif
t = try_then_request_module(xt_find_table_lock(net, NFPROTO_ARP, name),
"arptable_%s", name);
if (!IS_ERR_OR_NULL(t)) {
if (t) {
struct arpt_getinfo info;
const struct xt_table_info *private = t->private;
#ifdef CONFIG_COMPAT
Expand Down Expand Up @@ -834,7 +834,7 @@ 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(NFPROTO_ARP);
Expand All @@ -859,7 +859,7 @@ static int get_entries(struct net *net, struct arpt_get_entries __user *uptr,
get.name[sizeof(get.name) - 1] = '\0';

t = xt_find_table_lock(net, NFPROTO_ARP, get.name);
if (!IS_ERR_OR_NULL(t)) {
if (t) {
const struct xt_table_info *private = t->private;

if (get.size == private->size)
Expand All @@ -871,7 +871,7 @@ static int get_entries(struct net *net, struct arpt_get_entries __user *uptr,
module_put(t->me);
xt_table_unlock(t);
} else
ret = t ? PTR_ERR(t) : -ENOENT;
ret = -ENOENT;

return ret;
}
Expand All @@ -898,8 +898,8 @@ static int __do_replace(struct net *net, const char *name,

t = try_then_request_module(xt_find_table_lock(net, NFPROTO_ARP, name),
"arptable_%s", name);
if (IS_ERR_OR_NULL(t)) {
ret = t ? PTR_ERR(t) : -ENOENT;
if (!t) {
ret = -ENOENT;
goto free_newinfo_counters_untrans;
}

Expand Down Expand Up @@ -1014,8 +1014,8 @@ static int do_add_counters(struct net *net, const void __user *user,
return PTR_ERR(paddc);

t = xt_find_table_lock(net, NFPROTO_ARP, tmp.name);
if (IS_ERR_OR_NULL(t)) {
ret = t ? PTR_ERR(t) : -ENOENT;
if (!t) {
ret = -ENOENT;
goto free;
}

Expand Down Expand Up @@ -1404,7 +1404,7 @@ static int compat_get_entries(struct net *net,

xt_compat_lock(NFPROTO_ARP);
t = xt_find_table_lock(net, NFPROTO_ARP, get.name);
if (!IS_ERR_OR_NULL(t)) {
if (t) {
const struct xt_table_info *private = t->private;
struct xt_table_info info;

Expand All @@ -1419,7 +1419,7 @@ static int compat_get_entries(struct net *net,
module_put(t->me);
xt_table_unlock(t);
} else
ret = t ? PTR_ERR(t) : -ENOENT;
ret = -ENOENT;

xt_compat_unlock(NFPROTO_ARP);
return ret;
Expand Down
20 changes: 10 additions & 10 deletions net/ipv4/netfilter/ip_tables.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -973,7 +973,7 @@ static int get_info(struct net *net, void __user *user,
#endif
t = try_then_request_module(xt_find_table_lock(net, AF_INET, name),
"iptable_%s", name);
if (!IS_ERR_OR_NULL(t)) {
if (t) {
struct ipt_getinfo info;
const struct xt_table_info *private = t->private;
#ifdef CONFIG_COMPAT
Expand Down Expand Up @@ -1003,7 +1003,7 @@ 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_INET);
Expand All @@ -1028,7 +1028,7 @@ get_entries(struct net *net, struct ipt_get_entries __user *uptr,
get.name[sizeof(get.name) - 1] = '\0';

t = xt_find_table_lock(net, AF_INET, get.name);
if (!IS_ERR_OR_NULL(t)) {
if (t) {
const struct xt_table_info *private = t->private;
if (get.size == private->size)
ret = copy_entries_to_user(private->size,
Expand All @@ -1039,7 +1039,7 @@ get_entries(struct net *net, struct ipt_get_entries __user *uptr,
module_put(t->me);
xt_table_unlock(t);
} else
ret = t ? PTR_ERR(t) : -ENOENT;
ret = -ENOENT;

return ret;
}
Expand All @@ -1064,8 +1064,8 @@ __do_replace(struct net *net, const char *name, unsigned int valid_hooks,

t = try_then_request_module(xt_find_table_lock(net, AF_INET, name),
"iptable_%s", name);
if (IS_ERR_OR_NULL(t)) {
ret = t ? PTR_ERR(t) : -ENOENT;
if (!t) {
ret = -ENOENT;
goto free_newinfo_counters_untrans;
}

Expand Down Expand Up @@ -1180,8 +1180,8 @@ do_add_counters(struct net *net, const void __user *user,
return PTR_ERR(paddc);

t = xt_find_table_lock(net, AF_INET, tmp.name);
if (IS_ERR_OR_NULL(t)) {
ret = t ? PTR_ERR(t) : -ENOENT;
if (!t) {
ret = -ENOENT;
goto free;
}

Expand Down Expand Up @@ -1626,7 +1626,7 @@ compat_get_entries(struct net *net, struct compat_ipt_get_entries __user *uptr,

xt_compat_lock(AF_INET);
t = xt_find_table_lock(net, AF_INET, 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);
Expand All @@ -1640,7 +1640,7 @@ compat_get_entries(struct net *net, struct compat_ipt_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_INET);
return ret;
Expand Down
20 changes: 10 additions & 10 deletions net/ipv6/netfilter/ip6_tables.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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
Expand Down Expand Up @@ -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);
Expand All @@ -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,
Expand All @@ -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;
}
Expand All @@ -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;
}

Expand Down Expand Up @@ -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;
}

Expand Down Expand Up @@ -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);
Expand All @@ -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;
Expand Down
2 changes: 1 addition & 1 deletion net/netfilter/x_tables.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -982,7 +982,7 @@ void xt_free_table_info(struct xt_table_info *info)
}
EXPORT_SYMBOL(xt_free_table_info);

/* Find table by name, grabs mutex & ref. Returns ERR_PTR() on error. */
/* Find table by name, grabs mutex & ref. Returns NULL on error. */
struct xt_table *xt_find_table_lock(struct net *net, u_int8_t af,
const char *name)
{
Expand Down

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