netfilter: xtables: optimize call flow around xt_entry_foreach

Signed-off-by: Jan Engelhardt <jengelh@medozas.de>
Signed-off-by: Patrick McHardy <kaber@trash.net>

1 files changed, 58 insertions, 122 deletions

diff --git a/net/ipv4/netfilter/arp_tables.c b/net/ipv4/netfilter/arp_tables.c
index f7338869fc4..5fdedeb4621 100644
--- a/net/ipv4/netfilter/arp_tables.c
+++ b/net/ipv4/netfilter/arp_tables.c
@@ -512,8 +512,7 @@ static inline int check_target(struct arpt_entry *e, const char *name)
 }
 
 static inline int
-find_check_entry(struct arpt_entry *e, const char *name, unsigned int size,
-                 unsigned int *i)
+find_check_entry(struct arpt_entry *e, const char *name, unsigned int size)
 {
         struct arpt_entry_target *t;
         struct xt_target *target;
@@ -538,8 +537,6 @@ find_check_entry(struct arpt_entry *e, const char *name, unsigned int size,
         ret = check_target(e, name);
         if (ret)
                 goto err;
-
-        (*i)++;
         return 0;
 err:
         module_put(t->u.kernel.target->me);
@@ -568,8 +565,7 @@ static inline int check_entry_size_and_hooks(struct arpt_entry *e,
                                              const unsigned char *limit,
                                              const unsigned int *hook_entries,
                                              const unsigned int *underflows,
-                                             unsigned int valid_hooks,
-                                             unsigned int *i)
+                                             unsigned int valid_hooks)
 {
         unsigned int h;
 
@@ -606,19 +602,14 @@ static inline int check_entry_size_and_hooks(struct arpt_entry *e,
         /* Clear counters and comefrom */
         e->counters = ((struct xt_counters) { 0, 0 });
         e->comefrom = 0;
-
-        (*i)++;
         return 0;
 }
 
-static inline int cleanup_entry(struct arpt_entry *e, unsigned int *i)
+static inline void cleanup_entry(struct arpt_entry *e)
 {
         struct xt_tgdtor_param par;
         struct arpt_entry_target *t;
 
-        if (i && (*i)-- == 0)
-                return 1;
-
         t = arpt_get_target(e);
         par.target   = t->u.kernel.target;
         par.targinfo = t->data;
@@ -626,7 +617,6 @@ static inline int cleanup_entry(struct arpt_entry *e, unsigned int *i)
         if (par.target->destroy != NULL)
                 par.target->destroy(&par);
         module_put(par.target->me);
-        return 0;
 }
 
 /* Checks and translates the user-supplied table segment (held in
@@ -660,10 +650,10 @@ static int translate_table(const char *name,
         /* Walk through entries, checking offsets. */
         xt_entry_foreach(iter, entry0, newinfo->size) {
                 ret = check_entry_size_and_hooks(iter, newinfo, entry0,
-                      entry0 + size, hook_entries, underflows,
-                      valid_hooks, &i);
+                      entry0 + size, hook_entries, underflows, valid_hooks);
                 if (ret != 0)
                         break;
+                ++i;
         }
         duprintf("translate_table: ARPT_ENTRY_ITERATE gives %d\n", ret);
         if (ret != 0)
@@ -700,15 +690,18 @@ static int translate_table(const char *name,
         /* Finally, each sanity check must pass */
         i = 0;
         xt_entry_foreach(iter, entry0, newinfo->size) {
-                ret = find_check_entry(iter, name, size, &i);
+                ret = find_check_entry(iter, name, size);
                 if (ret != 0)
                         break;
+                ++i;
         }
 
         if (ret != 0) {
-                xt_entry_foreach(iter, entry0, newinfo->size)
-                        if (cleanup_entry(iter, &i) != 0)
+                xt_entry_foreach(iter, entry0, newinfo->size) {
+                        if (i-- == 0)
                                 break;
+                        cleanup_entry(iter);
+                }
                 return ret;
         }
 
@@ -721,27 +714,6 @@ static int translate_table(const char *name,
         return ret;
 }
 
-/* Gets counters. */
-static inline int add_entry_to_counter(const struct arpt_entry *e,
-                                       struct xt_counters total[],
-                                       unsigned int *i)
-{
-        ADD_COUNTER(total[*i], e->counters.bcnt, e->counters.pcnt);
-
-        (*i)++;
-        return 0;
-}
-
-static inline int set_entry_to_counter(const struct arpt_entry *e,
-                                       struct xt_counters total[],
-                                       unsigned int *i)
-{
-        SET_COUNTER(total[*i], e->counters.bcnt, e->counters.pcnt);
-
-        (*i)++;
-        return 0;
-}
-
 static void get_counters(const struct xt_table_info *t,
                          struct xt_counters counters[])
 {
@@ -761,18 +733,22 @@ static void get_counters(const struct xt_table_info *t,
         curcpu = smp_processor_id();
 
         i = 0;
-        xt_entry_foreach(iter, t->entries[curcpu], t->size)
-                if (set_entry_to_counter(iter, counters, &i) != 0)
-                        break;
+        xt_entry_foreach(iter, t->entries[curcpu], t->size) {
+                SET_COUNTER(counters[i], iter->counters.bcnt,
+                        iter->counters.pcnt);
+                ++i;
+        }
 
         for_each_possible_cpu(cpu) {
                 if (cpu == curcpu)
                         continue;
                 i = 0;
                 xt_info_wrlock(cpu);
-                xt_entry_foreach(iter, t->entries[cpu], t->size)
-                        if (add_entry_to_counter(iter, counters, &i) != 0)
-                                break;
+                xt_entry_foreach(iter, t->entries[cpu], t->size) {
+                        ADD_COUNTER(counters[i], iter->counters.bcnt,
+                                iter->counters.pcnt);
+                        ++i;
+                }
                 xt_info_wrunlock(cpu);
         }
         local_bh_enable();
@@ -904,7 +880,7 @@ static int compat_table_info(const struct xt_table_info *info,
 {
         struct arpt_entry *iter;
         void *loc_cpu_entry;
-        int ret = 0;
+        int ret;
 
         if (!newinfo || !info)
                 return -EINVAL;
@@ -916,9 +892,9 @@ static int compat_table_info(const struct xt_table_info *info,
         xt_entry_foreach(iter, loc_cpu_entry, info->size) {
                 ret = compat_calc_entry(iter, info, loc_cpu_entry, newinfo);
                 if (ret != 0)
-                        break;
+                        return ret;
         }
-        return ret;
+        return 0;
 }
 #endif
 
@@ -1078,8 +1054,7 @@ static int __do_replace(struct net *net, const char *name,
         /* Decrease module usage counts and free resource */
         loc_cpu_old_entry = oldinfo->entries[raw_smp_processor_id()];
         xt_entry_foreach(iter, loc_cpu_old_entry, oldinfo->size)
-                if (cleanup_entry(iter, NULL) != 0)
-                        break;
+                cleanup_entry(iter);
 
         xt_free_table_info(oldinfo);
         if (copy_to_user(counters_ptr, counters,
@@ -1142,26 +1117,12 @@ static int do_replace(struct net *net, const void __user *user,
 
  free_newinfo_untrans:
         xt_entry_foreach(iter, loc_cpu_entry, newinfo->size)
-                if (cleanup_entry(iter, NULL) != 0)
-                        break;
+                cleanup_entry(iter);
  free_newinfo:
         xt_free_table_info(newinfo);
         return ret;
 }
 
-/* We're lazy, and add to the first CPU; overflow works its fey magic
- * and everything is OK. */
-static int
-add_counter_to_entry(struct arpt_entry *e,
-                     const struct xt_counters addme[],
-                     unsigned int *i)
-{
-        ADD_COUNTER(e->counters, addme[*i].bcnt, addme[*i].pcnt);
-
-        (*i)++;
-        return 0;
-}
-
 static int do_add_counters(struct net *net, const void __user *user,
                            unsigned int len, int compat)
 {
@@ -1234,9 +1195,10 @@ static int do_add_counters(struct net *net, const void __user *user,
         curcpu = smp_processor_id();
         loc_cpu_entry = private->entries[curcpu];
         xt_info_wrlock(curcpu);
-        xt_entry_foreach(iter, loc_cpu_entry, private->size)
-                if (add_counter_to_entry(iter, paddc, &i) != 0)
-                        break;
+        xt_entry_foreach(iter, loc_cpu_entry, private->size) {
+                ADD_COUNTER(iter->counters, paddc[i].bcnt, paddc[i].pcnt);
+                ++i;
+        }
         xt_info_wrunlock(curcpu);
  unlock_up_free:
         local_bh_enable();
@@ -1249,17 +1211,12 @@ static int do_add_counters(struct net *net, const void __user *user,
 }
 
 #ifdef CONFIG_COMPAT
-static inline int
-compat_release_entry(struct compat_arpt_entry *e, unsigned int *i)
+static inline void compat_release_entry(struct compat_arpt_entry *e)
 {
         struct arpt_entry_target *t;
 
-        if (i && (*i)-- == 0)
-                return 1;
-
         t = compat_arpt_get_target(e);
         module_put(t->u.kernel.target->me);
-        return 0;
 }
 
 static inline int
@@ -1270,7 +1227,6 @@ check_compat_entry_size_and_hooks(struct compat_arpt_entry *e,
                                   const unsigned char *limit,
                                   const unsigned int *hook_entries,
                                   const unsigned int *underflows,
-                                  unsigned int *i,
                                   const char *name)
 {
         struct arpt_entry_target *t;
@@ -1330,8 +1286,6 @@ check_compat_entry_size_and_hooks(struct compat_arpt_entry *e,
         /* Clear counters and comefrom */
         memset(&e->counters, 0, sizeof(e->counters));
         e->comefrom = 0;
-
-        (*i)++;
         return 0;
 
 release_target:
@@ -1375,19 +1329,6 @@ compat_copy_entry_from_user(struct compat_arpt_entry *e, void **dstptr,
         return ret;
 }
 
-static inline int compat_check_entry(struct arpt_entry *e, const char *name,
-                                     unsigned int *i)
-{
-        int ret;
-
-        ret = check_target(e, name);
-        if (ret)
-                return ret;
-
-        (*i)++;
-        return 0;
-}
-
 static int translate_compat_table(const char *name,
                                   unsigned int valid_hooks,
                                   struct xt_table_info **pinfo,
@@ -1423,12 +1364,11 @@ static int translate_compat_table(const char *name,
         xt_entry_foreach(iter0, entry0, total_size) {
                 ret = check_compat_entry_size_and_hooks(iter0, info, &size,
                       entry0, entry0 + total_size, hook_entries, underflows,
-                      &j, name);
+                      name);
                 if (ret != 0)
-                        break;
+                        goto out_unlock;
+                ++j;
         }
-        if (ret != 0)
-                goto out_unlock;
 
         ret = -EINVAL;
         if (j != number) {
@@ -1484,9 +1424,10 @@ static int translate_compat_table(const char *name,
 
         i = 0;
         xt_entry_foreach(iter1, entry1, newinfo->size) {
-                ret = compat_check_entry(iter1, name, &i);
+                ret = check_target(iter1, name);
                 if (ret != 0)
                         break;
+                ++i;
         }
         if (ret) {
                 /*
@@ -1499,12 +1440,15 @@ static int translate_compat_table(const char *name,
                 xt_entry_foreach(iter0, entry0, newinfo->size) {
                         if (skip-- > 0)
                                 continue;
-                        if (compat_release_entry(iter0, &j) != 0)
+                        if (j-- == 0)
                                 break;
+                        compat_release_entry(iter0);
                 }
-                xt_entry_foreach(iter1, entry1, newinfo->size)
-                        if (cleanup_entry(iter1, &i) != 0)
+                xt_entry_foreach(iter1, entry1, newinfo->size) {
+                        if (i-- == 0)
                                 break;
+                        cleanup_entry(iter1);
+                }
                 xt_free_table_info(newinfo);
                 return ret;
         }
@@ -1522,9 +1466,11 @@ static int translate_compat_table(const char *name,
 free_newinfo:
         xt_free_table_info(newinfo);
 out:
-        xt_entry_foreach(iter0, entry0, total_size)
-                if (compat_release_entry(iter0, &j) != 0)
+        xt_entry_foreach(iter0, entry0, total_size) {
+                if (j-- == 0)
                         break;
+                compat_release_entry(iter0);
+        }
         return ret;
 out_unlock:
         xt_compat_flush_offsets(NFPROTO_ARP);
@@ -1590,8 +1536,7 @@ static int compat_do_replace(struct net *net, void __user *user,
 
  free_newinfo_untrans:
         xt_entry_foreach(iter, loc_cpu_entry, newinfo->size)
-                if (cleanup_entry(iter, NULL) != 0)
-                        break;
+                cleanup_entry(iter);
  free_newinfo:
         xt_free_table_info(newinfo);
         return ret;
@@ -1625,7 +1570,7 @@ static int compat_do_arpt_set_ctl(struct sock *sk, int cmd, void __user *user,
 static int compat_copy_entry_to_user(struct arpt_entry *e, void __user **dstptr,
                                      compat_uint_t *size,
                                      struct xt_counters *counters,
-                                     unsigned int *i)
+                                     unsigned int i)
 {
         struct arpt_entry_target *t;
         struct compat_arpt_entry __user *ce;
@@ -1633,14 +1578,12 @@ static int compat_copy_entry_to_user(struct arpt_entry *e, void __user **dstptr,
         compat_uint_t origsize;
         int ret;
 
-        ret = -EFAULT;
         origsize = *size;
         ce = (struct compat_arpt_entry __user *)*dstptr;
-        if (copy_to_user(ce, e, sizeof(struct arpt_entry)))
-                goto out;
-
-        if (copy_to_user(&ce->counters, &counters[*i], sizeof(counters[*i])))
-                goto out;
+        if (copy_to_user(ce, e, sizeof(struct arpt_entry)) != 0 ||
+            copy_to_user(&ce->counters, &counters[i],
+            sizeof(counters[i])) != 0)
+                return -EFAULT;
 
         *dstptr += sizeof(struct compat_arpt_entry);
         *size -= sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
@@ -1650,18 +1593,12 @@ static int compat_copy_entry_to_user(struct arpt_entry *e, void __user **dstptr,
         t = arpt_get_target(e);
         ret = xt_compat_target_to_user(t, dstptr, size);
         if (ret)
-                goto out;
-        ret = -EFAULT;
+                return ret;
         next_offset = e->next_offset - (origsize - *size);
-        if (put_user(target_offset, &ce->target_offset))
-                goto out;
-        if (put_user(next_offset, &ce->next_offset))
-                goto out;
-
-        (*i)++;
+        if (put_user(target_offset, &ce->target_offset) != 0 ||
+            put_user(next_offset, &ce->next_offset) != 0)
+                return -EFAULT;
         return 0;
-out:
-        return ret;
 }
 
 static int compat_copy_entries_to_user(unsigned int total_size,
@@ -1687,7 +1624,7 @@ static int compat_copy_entries_to_user(unsigned int total_size,
         size = total_size;
         xt_entry_foreach(iter, loc_cpu_entry, total_size) {
                 ret = compat_copy_entry_to_user(iter, &pos,
-                      &size, counters, &i);
+                      &size, counters, i++);
                 if (ret != 0)
                         break;
         }
@@ -1893,8 +1830,7 @@ void arpt_unregister_table(struct xt_table *table)
         /* Decrease module usage counts and free resources */
         loc_cpu_entry = private->entries[raw_smp_processor_id()];
         xt_entry_foreach(iter, loc_cpu_entry, private->size)
-                if (cleanup_entry(iter, NULL) != 0)
-                        break;
+                cleanup_entry(iter);
         if (private->number > private->initial_entries)
                 module_put(table_owner);
         xt_free_table_info(private);