From: Eric Dumazet Date: Mon, 15 Jun 2015 16:57:30 +0000 (-0700) Subject: netfilter: x_tables: remove XT_TABLE_INFO_SZ and a dereference. X-Git-Url: http://git.cdn.openwrt.org/?a=commitdiff_plain;h=711bdde6a884354ddae8da2fcb495b2a9364cc90;p=openwrt%2Fstaging%2Fblogic.git netfilter: x_tables: remove XT_TABLE_INFO_SZ and a dereference. 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 Cc: Florian Westphal Signed-off-by: Pablo Neira Ayuso --- diff --git a/include/linux/netfilter/x_tables.h b/include/linux/netfilter/x_tables.h index 9969d79dcde1..95693c4cebdd 100644 --- a/include/linux/netfilter/x_tables.h +++ b/include/linux/netfilter/x_tables.h @@ -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); diff --git a/net/ipv4/netfilter/arp_tables.c b/net/ipv4/netfilter/arp_tables.c index d75c139393fc..95c9b6eece25 100644 --- a/net/ipv4/netfilter/arp_tables.c +++ b/net/ipv4/netfilter/arp_tables.c @@ -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) diff --git a/net/ipv4/netfilter/ip_tables.c b/net/ipv4/netfilter/ip_tables.c index 6151500c2df8..6c72fbb7b49e 100644 --- a/net/ipv4/netfilter/ip_tables.c +++ b/net/ipv4/netfilter/ip_tables.c @@ -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) diff --git a/net/ipv6/netfilter/ip6_tables.c b/net/ipv6/netfilter/ip6_tables.c index 80a7f0d38aa4..3c35ced39b42 100644 --- a/net/ipv6/netfilter/ip6_tables.c +++ b/net/ipv6/netfilter/ip6_tables.c @@ -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) diff --git a/net/netfilter/x_tables.c b/net/netfilter/x_tables.c index 6062ce3e862c..d324fe71260c 100644 --- a/net/netfilter/x_tables.c +++ b/net/netfilter/x_tables.c @@ -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);