[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>

1 files changed, 2 insertions, 3 deletions

diff --git a/net/ipv6/netfilter/ip6_tables.c b/net/ipv6/netfilter/ip6_tables.c
index e1e87eff4686..e60c1b4b1ec8 100644
--- a/net/ipv6/netfilter/ip6_tables.c
+++ b/net/ipv6/netfilter/ip6_tables.c
@@ -1042,8 +1042,7 @@ do_replace(void __user *user, unsigned int len)
                 return -EFAULT;
 
         /* 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;
@@ -1339,7 +1338,7 @@ int ip6t_register_table(struct xt_table *table,
 {
         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;