Gitweb:     
http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=259d4e41f3ec25f22169daece42729f597b89f9a
Commit:     259d4e41f3ec25f22169daece42729f597b89f9a
Parent:     d3c5ee6d545b5372fd525ebe16988a5b6efeceb0
Author:     Eric Dumazet <[EMAIL PROTECTED]>
AuthorDate: Tue Dec 4 23:24:56 2007 -0800
Committer:  David S. Miller <[EMAIL PROTECTED]>
CommitDate: Mon Jan 28 14:55:54 2008 -0800

    [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 <[EMAIL PROTECTED]>
    Signed-off-by: Patrick McHardy <[EMAIL PROTECTED]>
    Signed-off-by: David S. Miller <[EMAIL PROTECTED]>
---
 include/linux/netfilter/x_tables.h |    5 ++++-
 net/ipv4/netfilter/arp_tables.c    |    5 ++---
 net/ipv4/netfilter/ip_tables.c     |   24 +++++++++---------------
 net/ipv6/netfilter/ip6_tables.c    |    5 ++---
 net/netfilter/x_tables.c           |    2 +-
 5 files changed, 18 insertions(+), 23 deletions(-)

diff --git a/include/linux/netfilter/x_tables.h 
b/include/linux/netfilter/x_tables.h
index 9657c4e..e305f2d 100644
--- a/include/linux/netfilter/x_tables.h
+++ b/include/linux/netfilter/x_tables.h
@@ -269,9 +269,12 @@ struct xt_table_info
        unsigned int underflow[NF_INET_NUMHOOKS];
 
        /* ipt_entry tables: one per CPU */
-       char *entries[NR_CPUS];
+       /* Note : this field MUST be the last one, see XT_TABLE_INFO_SZ */
+       char *entries[1];
 };
 
+#define XT_TABLE_INFO_SZ (offsetof(struct xt_table_info, entries) \
+                         + nr_cpu_ids * sizeof(char *))
 extern int xt_register_target(struct xt_target *target);
 extern void xt_unregister_target(struct xt_target *target);
 extern int xt_register_targets(struct xt_target *target, unsigned int n);
diff --git a/net/ipv4/netfilter/arp_tables.c b/net/ipv4/netfilter/arp_tables.c
index 2909c92..a21722d 100644
--- a/net/ipv4/netfilter/arp_tables.c
+++ b/net/ipv4/netfilter/arp_tables.c
@@ -811,8 +811,7 @@ static int do_replace(void __user *user, unsigned int len)
                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;
@@ -1090,7 +1089,7 @@ int arpt_register_table(struct arpt_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;
 
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 @@ compat_calc_match(struct ipt_entry_match *m, int * size)
        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 @@ static int compat_calc_entry(struct ipt_entry *e, 
struct xt_table_info *info,
        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 @@ do_replace(void __user *user, unsigned int len)
                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 @@ compat_do_replace(void __user *user, unsigned int len)
                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 ipt_register_table(struct xt_table *table, const 
struct ipt_replace *repl)
 {
        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;
 
diff --git a/net/ipv6/netfilter/ip6_tables.c b/net/ipv6/netfilter/ip6_tables.c
index e1e87ef..e60c1b4 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;
 
diff --git a/net/netfilter/x_tables.c b/net/netfilter/x_tables.c
index b6160e4..07bb465 100644
--- a/net/netfilter/x_tables.c
+++ b/net/netfilter/x_tables.c
@@ -499,7 +499,7 @@ struct xt_table_info *xt_alloc_table_info(unsigned int size)
        if ((SMP_ALIGN(size) >> PAGE_SHIFT) + 2 > num_physpages)
                return NULL;
 
-       newinfo = kzalloc(sizeof(struct xt_table_info), GFP_KERNEL);
+       newinfo = kzalloc(XT_TABLE_INFO_SZ, GFP_KERNEL);
        if (!newinfo)
                return NULL;
 
-
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