* Re: net/sched/ipt.c
2005-01-06 4:33 net/sched/ipt.c Andrew Morton
@ 2005-01-06 4:46 ` Rusty Russell
0 siblings, 0 replies; 2+ messages in thread
From: Rusty Russell @ 2005-01-06 4:46 UTC (permalink / raw)
To: Andrew Morton; +Cc: netdev
On Wed, 2005-01-05 at 20:33 -0800, Andrew Morton wrote:
> Am I missing something?
>
> *** Warning: "__ipt_mutex_up" [net/sched/ipt.ko] undefined!
> *** Warning: "__ipt_find_target_lock" [net/sched/ipt.ko] undefined!
Patch already sent...
Rusty.
Name: Restore net/sched/ipt.c After iptables Kmod Cleanup
Status: Tested under nfsim
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Thomas Graf points out that I broke net/sched/ipt.c when I removed
__ipt_find_target_lock. In fact, those routines don't need to keep
the lock held, so we can simplify them, and expose an interface
(ipt_find_target) which does module loading correctly for
net/sched/ipt.c.
As Thomas points out, this also gets the module refcounts right.
Index: linux-2.6.10-bk8-Netfilter/net/ipv4/netfilter/ip_tables.c
===================================================================
--- linux-2.6.10-bk8-Netfilter.orig/net/ipv4/netfilter/ip_tables.c 2005-01-06 09:12:01.000000000 +1100
+++ linux-2.6.10-bk8-Netfilter/net/ipv4/netfilter/ip_tables.c 2005-01-06 09:49:10.000000000 +1100
@@ -430,62 +430,63 @@
return NULL;
}
-/* Find match, grabs mutex & ref. Returns ERR_PTR() on error. */
-static inline struct ipt_match *find_match_lock(const char *name, u8 revision)
+/* Find match, grabs ref. Returns ERR_PTR() on error. */
+static inline struct ipt_match *find_match(const char *name, u8 revision)
{
struct ipt_match *m;
- int found = 0;
+ int err = 0;
if (down_interruptible(&ipt_mutex) != 0)
return ERR_PTR(-EINTR);
list_for_each_entry(m, &ipt_match, list) {
if (strcmp(m->name, name) == 0) {
- found = 1;
if (m->revision == revision) {
- if (!try_module_get(m->me))
- found = 0;
- else
+ if (try_module_get(m->me)) {
+ up(&ipt_mutex);
return m;
- }
+ }
+ } else
+ err = -EPROTOTYPE; /* Found something. */
}
}
up(&ipt_mutex);
-
- /* Not found at all? NULL so try_then_request_module loads module. */
- if (!found)
- return NULL;
-
- return ERR_PTR(-EPROTOTYPE);
+ return ERR_PTR(err);
}
-/* Find target, grabs mutex & ref. Returns ERR_PTR() on error. */
-static inline struct ipt_target *find_target_lock(const char *name, u8 revision)
+/* Find target, grabs ref. Returns ERR_PTR() on error. */
+static inline struct ipt_target *find_target(const char *name, u8 revision)
{
struct ipt_target *t;
- int found = 0;
+ int err = 0;
if (down_interruptible(&ipt_mutex) != 0)
return ERR_PTR(-EINTR);
list_for_each_entry(t, &ipt_target, list) {
if (strcmp(t->name, name) == 0) {
- found = 1;
if (t->revision == revision) {
- if (!try_module_get(t->me))
- found = 0;
- else
+ if (try_module_get(t->me)) {
+ up(&ipt_mutex);
return t;
- }
+ }
+ } else
+ err = -EPROTOTYPE; /* Found something. */
}
}
up(&ipt_mutex);
+ return ERR_PTR(err);
+}
- /* Not found at all? NULL so try_then_request_module loads module. */
- if (!found)
- return NULL;
+struct ipt_target *ipt_find_target(const char *name, u8 revision)
+{
+ struct ipt_target *target;
- return ERR_PTR(-EPROTOTYPE);
+ target = try_then_request_module(find_target(name, revision),
+ "ipt_%s", name);
+ if (IS_ERR(target) || !target)
+ return NULL;
+ return target;
}
static int match_revfn(const char *name, u8 revision, int *bestp)
@@ -708,15 +709,14 @@
{
struct ipt_match *match;
- match = try_then_request_module(find_match_lock(m->u.user.name,
- m->u.user.revision),
+ match = try_then_request_module(find_match(m->u.user.name,
+ m->u.user.revision),
"ipt_%s", m->u.user.name);
if (IS_ERR(match) || !match) {
duprintf("check_match: `%s' not found\n", m->u.user.name);
return match ? PTR_ERR(match) : -ENOENT;
}
m->u.kernel.match = match;
- up(&ipt_mutex);
if (m->u.kernel.match->checkentry
&& !m->u.kernel.match->checkentry(name, ip, m->data,
@@ -754,8 +754,8 @@
goto cleanup_matches;
t = ipt_get_target(e);
- target = try_then_request_module(find_target_lock(t->u.user.name,
- t->u.user.revision),
+ target = try_then_request_module(find_target(t->u.user.name,
+ t->u.user.revision),
"ipt_%s", t->u.user.name);
if (IS_ERR(target) || !target) {
duprintf("check_entry: `%s' not found\n", t->u.user.name);
@@ -763,7 +763,6 @@
goto cleanup_matches;
}
t->u.kernel.target = target;
- up(&ipt_mutex);
if (t->u.kernel.target == &ipt_standard_target) {
if (!standard_check(t, size)) {
Index: linux-2.6.10-bk8-Netfilter/net/sched/ipt.c
===================================================================
--- linux-2.6.10-bk8-Netfilter.orig/net/sched/ipt.c 2004-12-28 12:31:11.000000000 +1100
+++ linux-2.6.10-bk8-Netfilter/net/sched/ipt.c 2005-01-06 09:37:01.000000000 +1100
@@ -31,6 +31,7 @@
#include <linux/module.h>
#include <linux/init.h>
#include <linux/proc_fs.h>
+#include <linux/kmod.h>
#include <net/sock.h>
#include <net/pkt_sched.h>
#include <linux/tc_act/tc_ipt.h>
@@ -60,32 +61,23 @@
struct ipt_target *target;
int ret = 0;
struct ipt_entry_target *t = p->t;
- target = __ipt_find_target_lock(t->u.user.name, &ret);
+ target = ipt_find_target(t->u.user.name, t->u.user.revision);
if (!target) {
printk("init_targ: Failed to find %s\n", t->u.user.name);
return -1;
}
DPRINTK("init_targ: found %s\n", target->name);
- /* we really need proper ref counting
- seems to be only needed for modules?? Talk to laforge */
-/* if (target->me)
- __MOD_INC_USE_COUNT(target->me);
-*/
t->u.kernel.target = target;
- __ipt_mutex_up();
-
if (t->u.kernel.target->checkentry
&& !t->u.kernel.target->checkentry(p->tname, NULL, t->data,
t->u.target_size
- sizeof (*t), p->hook)) {
-/* if (t->u.kernel.target->me)
- __MOD_DEC_USE_COUNT(t->u.kernel.target->me);
-*/
DPRINTK("ip_tables: check failed for `%s'.\n",
t->u.kernel.target->name);
+ module_put(t->u.kernel.target->me);
ret = -EINVAL;
}
@@ -235,8 +227,12 @@
{
struct tcf_ipt *p;
p = PRIV(a,ipt);
- if (NULL != p)
+ if (NULL != p) {
+ struct ipt_entry_target *t = p->t;
+ if (t && t->u.kernel.target)
+ module_put(t->u.kernel.target->me);
return tcf_hash_release(p, bind);
+ }
return 0;
}
Index: linux-2.6.10-bk8-Netfilter/include/linux/netfilter_ipv4/ip_tables.h
===================================================================
--- linux-2.6.10-bk8-Netfilter.orig/include/linux/netfilter_ipv4/ip_tables.h 2005-01-06 09:11:56.000000000 +1100
+++ linux-2.6.10-bk8-Netfilter/include/linux/netfilter_ipv4/ip_tables.h 2005-01-06 09:40:03.000000000 +1100
@@ -456,6 +456,9 @@
struct module *me;
};
+/* net/sched/ipt.c: Gimme access to your targets! Gets target->me. */
+extern struct ipt_target *ipt_find_target(const char *name, u8 revision);
+
extern int ipt_register_table(struct ipt_table *table);
extern void ipt_unregister_table(struct ipt_table *table);
extern unsigned int ipt_do_table(struct sk_buff **pskb,
--
A bad analogy is like a leaky screwdriver -- Richard Braakman
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