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netfilter: x_tables: remove XT_TABLE_INFO_SZ and a dereference.

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After Florian patches, there is no need for XT_TABLE_INFO_SZ anymore :
Only one copy of table is kept, instead of one copy per cpu.

We also can avoid a dereference if we put table data right after
xt_table_info. It reduces register pressure and helps compiler.

Then, we attempt a kmalloc() if total size is under order-3 allocation,
to reduce TLB pressure, as in many cases, rules fit in 32 KB.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This commit is contained in:
Eric Dumazet 2015-06-15 09:57:30 -07:00 committed by Pablo Neira Ayuso
parent 53b8762727
commit 711bdde6a8
5 changed files with 19 additions and 30 deletions
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5
include/linux/netfilter/x_tables.h
View File

@ -225,12 +225,9 @@ struct xt_table_info {
unsigned int __percpu *stackptr;
void ***jumpstack;
/* Note : this field MUST be the last one, see XT_TABLE_INFO_SZ */
void *entries;
unsigned char entries[0] __aligned(8);
};
#define XT_TABLE_INFO_SZ (offsetof(struct xt_table_info, entries) \
+ nr_cpu_ids * sizeof(char *))
int xt_register_target(struct xt_target *target);
void xt_unregister_target(struct xt_target *target);
int xt_register_targets(struct xt_target *target, unsigned int n);

4
net/ipv4/netfilter/arp_tables.c
View File

@ -256,7 +256,7 @@ unsigned int arpt_do_table(struct sk_buff *skb,
const struct arphdr *arp;
struct arpt_entry *e, *back;
const char *indev, *outdev;
void *table_base;
const void *table_base;
const struct xt_table_info *private;
struct xt_action_param acpar;
unsigned int addend;
@ -868,7 +868,7 @@ static int compat_table_info(const struct xt_table_info *info,
struct xt_table_info *newinfo)
{
struct arpt_entry *iter;
void *loc_cpu_entry;
const void *loc_cpu_entry;
int ret;
if (!newinfo || !info)

4
net/ipv4/netfilter/ip_tables.c
View File

@ -938,7 +938,7 @@ copy_entries_to_user(unsigned int total_size,
struct xt_counters *counters;
const struct xt_table_info *private = table->private;
int ret = 0;
void *loc_cpu_entry;
const void *loc_cpu_entry;
counters = alloc_counters(table);
if (IS_ERR(counters))
@ -1052,7 +1052,7 @@ static int compat_table_info(const struct xt_table_info *info,
struct xt_table_info *newinfo)
{
struct ipt_entry *iter;
void *loc_cpu_entry;
const void *loc_cpu_entry;
int ret;
if (!newinfo || !info)

4
net/ipv6/netfilter/ip6_tables.c
View File

@ -951,7 +951,7 @@ copy_entries_to_user(unsigned int total_size,
struct xt_counters *counters;
const struct xt_table_info *private = table->private;
int ret = 0;
void *loc_cpu_entry;
const void *loc_cpu_entry;
counters = alloc_counters(table);
if (IS_ERR(counters))
@ -1065,7 +1065,7 @@ static int compat_table_info(const struct xt_table_info *info,
struct xt_table_info *newinfo)
{
struct ip6t_entry *iter;
void *loc_cpu_entry;
const void *loc_cpu_entry;
int ret;
if (!newinfo || !info)

32
net/netfilter/x_tables.c
View File

@ -658,29 +658,23 @@ EXPORT_SYMBOL_GPL(xt_compat_target_to_user);
struct xt_table_info *xt_alloc_table_info(unsigned int size)
{
struct xt_table_info *newinfo;
struct xt_table_info *info = NULL;
size_t sz = sizeof(*info) + size;
/* Pedantry: prevent them from hitting BUG() in vmalloc.c --RR */
if ((SMP_ALIGN(size) >> PAGE_SHIFT) + 2 > totalram_pages)
return NULL;
newinfo = kzalloc(XT_TABLE_INFO_SZ, GFP_KERNEL);
if (!newinfo)
return NULL;
newinfo->size = size;
if (size <= PAGE_SIZE)
newinfo->entries = kmalloc(size, GFP_KERNEL);
else
newinfo->entries = vmalloc(size);
if (newinfo->entries == NULL) {
xt_free_table_info(newinfo);
return NULL;
if (sz <= (PAGE_SIZE << PAGE_ALLOC_COSTLY_ORDER))
info = kmalloc(sz, GFP_KERNEL | __GFP_NOWARN | __GFP_NORETRY);
if (!info) {
info = vmalloc(sz);
if (!info)
return NULL;
}
return newinfo;
memset(info, 0, sizeof(*info));
info->size = size;
return info;
}
EXPORT_SYMBOL(xt_alloc_table_info);
@ -688,8 +682,6 @@ void xt_free_table_info(struct xt_table_info *info)
{
int cpu;
kvfree(info->entries);
if (info->jumpstack != NULL) {
for_each_possible_cpu(cpu)
kvfree(info->jumpstack[cpu]);
@ -698,7 +690,7 @@ void xt_free_table_info(struct xt_table_info *info)
free_percpu(info->stackptr);
kfree(info);
kvfree(info);
}
EXPORT_SYMBOL(xt_free_table_info);