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geoip: use rcu to reduce time spinlocks are held

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spin_lock_bh does not look safe (only disables preempt on current
CPU?). Change to spin_lock, that also avoids the management overhead
of spin_lock_bh. to spin_lock to avoid management overhead.

Use rcu in match and destroy function.
This commit is contained in:
Jan Engelhardt
2008-03-18 03:46:56 +01:00
parent 000d813171
commit 52a0ed7f15
1 changed files with 20 additions and 17 deletions
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37
extensions/xt_geoip.c
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@@ -13,6 +13,7 @@
#include <linux/list.h> #include <linux/list.h>
#include <linux/module.h> #include <linux/module.h>
#include <linux/netdevice.h> #include <linux/netdevice.h>
#include <linux/rcupdate.h>
#include <linux/skbuff.h> #include <linux/skbuff.h>
#include <linux/version.h> #include <linux/version.h>
#include <linux/vmalloc.h> #include <linux/vmalloc.h>
@@ -37,7 +38,7 @@ struct geoip_country_kernel {
}; };
static LIST_HEAD(geoip_head); static LIST_HEAD(geoip_head);
static spinlock_t geoip_lock = SPIN_LOCK_UNLOCKED; static DEFINE_SPINLOCK(geoip_lock);
static struct geoip_country_kernel * static struct geoip_country_kernel *
geoip_add_node(const struct geoip_country_user __user *umem_ptr) geoip_add_node(const struct geoip_country_user __user *umem_ptr)
@@ -63,15 +64,16 @@ geoip_add_node(const struct geoip_country_user __user *umem_ptr)
p->count * sizeof(struct geoip_subnet)) != 0) p->count * sizeof(struct geoip_subnet)) != 0)
goto free_s; goto free_s;
spin_lock_bh(&geoip_lock);
p->subnets = s; p->subnets = s;
atomic_set(&p->ref, 1); atomic_set(&p->ref, 1);
INIT_LIST_HEAD(&p->list); INIT_LIST_HEAD(&p->list);
list_add_tail(&p->list, &geoip_head);
spin_unlock_bh(&geoip_lock); spin_lock(&geoip_lock);
list_add_tail_rcu(&p->list, &geoip_head);
spin_unlock(&geoip_lock);
return p; return p;
free_s: free_s:
vfree(s); vfree(s);
free_p: free_p:
@@ -81,18 +83,19 @@ geoip_add_node(const struct geoip_country_user __user *umem_ptr)
static void geoip_try_remove_node(struct geoip_country_kernel *p) static void geoip_try_remove_node(struct geoip_country_kernel *p)
{ {
spin_lock_bh(&geoip_lock); spin_lock(&geoip_lock);
if (!atomic_dec_and_test(&p->ref)) { if (!atomic_dec_and_test(&p->ref)) {
spin_unlock_bh(&geoip_lock); spin_unlock(&geoip_lock);
return; return;
} }
list_del(&p->list);
/* So now am unlinked or the only one alive, right ? /* So now am unlinked or the only one alive, right ?
* What are you waiting ? Free up some memory! * What are you waiting ? Free up some memory!
*/ */
spin_unlock_bh(&geoip_lock); list_del_rcu(&p->list);
spin_unlock(&geoip_lock);
synchronize_rcu();
vfree(p->subnets); vfree(p->subnets);
kfree(p); kfree(p);
return; return;
@@ -101,16 +104,16 @@ static void geoip_try_remove_node(struct geoip_country_kernel *p)
static struct geoip_country_kernel *find_node(u_int16_t cc) static struct geoip_country_kernel *find_node(u_int16_t cc)
{ {
struct geoip_country_kernel *p; struct geoip_country_kernel *p;
spin_lock_bh(&geoip_lock); spin_lock(&geoip_lock);
list_for_each_entry(p, &geoip_head, list) list_for_each_entry_rcu(p, &geoip_head, list)
if (p->cc == cc) { if (p->cc == cc) {
atomic_inc(&p->ref); atomic_inc(&p->ref);
spin_unlock_bh(&geoip_lock); spin_unlock(&geoip_lock);
return p; return p;
} }
spin_unlock_bh(&geoip_lock); spin_unlock(&geoip_lock);
return NULL; return NULL;
} }
@@ -147,7 +150,7 @@ static bool xt_geoip_mt(const struct sk_buff *skb, const struct net_device *in,
else else
ip = ntohl(iph->daddr); ip = ntohl(iph->daddr);
spin_lock_bh(&geoip_lock); rcu_read_lock();
for (i = 0; i < info->count; i++) { for (i = 0; i < info->count; i++) {
if ((node = info->mem[i].kernel) == NULL) { if ((node = info->mem[i].kernel) == NULL) {
printk(KERN_ERR "xt_geoip: what the hell ?? '%c%c' isn't loaded into memory... skip it!\n", printk(KERN_ERR "xt_geoip: what the hell ?? '%c%c' isn't loaded into memory... skip it!\n",
@@ -157,12 +160,12 @@ static bool xt_geoip_mt(const struct sk_buff *skb, const struct net_device *in,
} }
if (geoip_bsearch(node->subnets, ip, 0, node->count)) { if (geoip_bsearch(node->subnets, ip, 0, node->count)) {
spin_unlock_bh(&geoip_lock); rcu_read_unlock();
return (info->flags & XT_GEOIP_INV) ? 0 : 1; return (info->flags & XT_GEOIP_INV) ? 0 : 1;
} }
} }
spin_unlock_bh(&geoip_lock); rcu_read_unlock();
return (info->flags & XT_GEOIP_INV) ? 1 : 0; return (info->flags & XT_GEOIP_INV) ? 1 : 0;
} }