[NETFILTER]: x_tables: struct xt_table_info diet
Instead of using a big array of NR_CPUS entries, we can compute the size
needed at runtime, using nr_cpu_ids
This should save some ram (especially on David's machines where NR_CPUS=4096 :
32 KB can be saved per table, and 64KB for dynamically allocated ones (because
of slab/slub alignements) )
In particular, the 'bootstrap' tables are not any more static (in data
section) but on stack as their size is now very small.
This also should reduce the size used on stack in compat functions
(get_info() declares an automatic variable, that could be bigger than kernel
stack size for big NR_CPUS)
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/netfilter/ip_tables.c b/net/ipv4/netfilter/ip_tables.c
index ca23c63..87d3692 100644
--- a/net/ipv4/netfilter/ip_tables.c
+++ b/net/ipv4/netfilter/ip_tables.c
@@ -1090,7 +1090,8 @@
return 0;
}
-static int compat_calc_entry(struct ipt_entry *e, struct xt_table_info *info,
+static int compat_calc_entry(struct ipt_entry *e,
+ const struct xt_table_info *info,
void *base, struct xt_table_info *newinfo)
{
struct ipt_entry_target *t;
@@ -1118,22 +1119,17 @@
return 0;
}
-static int compat_table_info(struct xt_table_info *info,
+static int compat_table_info(const struct xt_table_info *info,
struct xt_table_info *newinfo)
{
void *loc_cpu_entry;
- int i;
if (!newinfo || !info)
return -EINVAL;
- memset(newinfo, 0, sizeof(struct xt_table_info));
- newinfo->size = info->size;
- newinfo->number = info->number;
- for (i = 0; i < NF_INET_NUMHOOKS; i++) {
- newinfo->hook_entry[i] = info->hook_entry[i];
- newinfo->underflow[i] = info->underflow[i];
- }
+ /* we dont care about newinfo->entries[] */
+ memcpy(newinfo, info, offsetof(struct xt_table_info, entries));
+ newinfo->initial_entries = 0;
loc_cpu_entry = info->entries[raw_smp_processor_id()];
return IPT_ENTRY_ITERATE(loc_cpu_entry, info->size,
compat_calc_entry, info, loc_cpu_entry, newinfo);
@@ -1327,8 +1323,7 @@
return -ENOPROTOOPT;
/* overflow check */
- if (tmp.size >= (INT_MAX - sizeof(struct xt_table_info)) / NR_CPUS -
- SMP_CACHE_BYTES)
+ if (tmp.size >= INT_MAX / num_possible_cpus())
return -ENOMEM;
if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
return -ENOMEM;
@@ -1868,8 +1863,7 @@
return -ENOPROTOOPT;
/* overflow check */
- if (tmp.size >= (INT_MAX - sizeof(struct xt_table_info)) / NR_CPUS -
- SMP_CACHE_BYTES)
+ if (tmp.size >= INT_MAX / num_possible_cpus())
return -ENOMEM;
if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
return -ENOMEM;
@@ -2126,7 +2120,7 @@
{
int ret;
struct xt_table_info *newinfo;
- static struct xt_table_info bootstrap
+ struct xt_table_info bootstrap
= { 0, 0, 0, { 0 }, { 0 }, { } };
void *loc_cpu_entry;