*
* This source is covered by the GNU GPL, the same as all kernel sources.
*
- * Version: $Id: inetpeer.c,v 1.7 2001/09/20 21:22:50 davem Exp $
- *
* Authors: Andrey V. Savochkin <saw@msu.ru>
*/
#include <linux/interrupt.h>
#include <linux/spinlock.h>
#include <linux/random.h>
-#include <linux/sched.h>
#include <linux/timer.h>
#include <linux/time.h>
#include <linux/kernel.h>
#include <linux/net.h>
#include <net/ip.h>
#include <net/inetpeer.h>
+#include <net/secure_seq.h>
/*
* Theory of operations.
* lookups performed with disabled BHs.
*
* Serialisation issues.
- * 1. Nodes may appear in the tree only with the pool write lock held.
- * 2. Nodes may disappear from the tree only with the pool write lock held
+ * 1. Nodes may appear in the tree only with the pool lock held.
+ * 2. Nodes may disappear from the tree only with the pool lock held
* AND reference count being 0.
* 3. Nodes appears and disappears from unused node list only under
* "inet_peer_unused_lock".
* 4. Global variable peer_total is modified under the pool lock.
* 5. struct inet_peer fields modification:
* avl_left, avl_right, avl_parent, avl_height: pool lock
- * unused_next, unused_prevp: unused node list lock
+ * unused: unused node list lock
* refcnt: atomically against modifications on other CPU;
* usually under some other lock to prevent node disappearing
* dtime: unused node list lock
- * v4daddr: unchangeable
- * ip_id_count: idlock
+ * daddr: unchangeable
+ * ip_id_count: atomic value (no lock needed)
*/
-/* Exported for inet_getid inline function. */
-DEFINE_SPINLOCK(inet_peer_idlock);
-
-static kmem_cache_t *peer_cachep __read_mostly;
+static struct kmem_cache *peer_cachep __read_mostly;
#define node_height(x) x->avl_height
-static struct inet_peer peer_fake_node = {
- .avl_left = &peer_fake_node,
- .avl_right = &peer_fake_node,
+
+#define peer_avl_empty ((struct inet_peer *)&peer_fake_node)
+#define peer_avl_empty_rcu ((struct inet_peer __rcu __force *)&peer_fake_node)
+static const struct inet_peer peer_fake_node = {
+ .avl_left = peer_avl_empty_rcu,
+ .avl_right = peer_avl_empty_rcu,
.avl_height = 0
};
-#define peer_avl_empty (&peer_fake_node)
-static struct inet_peer *peer_root = peer_avl_empty;
-static DEFINE_RWLOCK(peer_pool_lock);
+
+struct inet_peer_base {
+ struct inet_peer __rcu *root;
+ spinlock_t lock;
+ int total;
+};
+
+static struct inet_peer_base v4_peers = {
+ .root = peer_avl_empty_rcu,
+ .lock = __SPIN_LOCK_UNLOCKED(v4_peers.lock),
+ .total = 0,
+};
+
+static struct inet_peer_base v6_peers = {
+ .root = peer_avl_empty_rcu,
+ .lock = __SPIN_LOCK_UNLOCKED(v6_peers.lock),
+ .total = 0,
+};
+
#define PEER_MAXDEPTH 40 /* sufficient for about 2^27 nodes */
-static int peer_total;
/* Exported for sysctl_net_ipv4. */
-int inet_peer_threshold = 65536 + 128; /* start to throw entries more
+int inet_peer_threshold __read_mostly = 65536 + 128; /* start to throw entries more
* aggressively at this stage */
-int inet_peer_minttl = 120 * HZ; /* TTL under high load: 120 sec */
-int inet_peer_maxttl = 10 * 60 * HZ; /* usual time to live: 10 min */
-
-static struct inet_peer *inet_peer_unused_head;
-/* Exported for inet_putpeer inline function. */
-struct inet_peer **inet_peer_unused_tailp = &inet_peer_unused_head;
-DEFINE_SPINLOCK(inet_peer_unused_lock);
-#define PEER_MAX_CLEANUP_WORK 30
+int inet_peer_minttl __read_mostly = 120 * HZ; /* TTL under high load: 120 sec */
+int inet_peer_maxttl __read_mostly = 10 * 60 * HZ; /* usual time to live: 10 min */
+int inet_peer_gc_mintime __read_mostly = 10 * HZ;
+int inet_peer_gc_maxtime __read_mostly = 120 * HZ;
+
+static struct {
+ struct list_head list;
+ spinlock_t lock;
+} unused_peers = {
+ .list = LIST_HEAD_INIT(unused_peers.list),
+ .lock = __SPIN_LOCK_UNLOCKED(unused_peers.lock),
+};
static void peer_check_expire(unsigned long dummy);
static DEFINE_TIMER(peer_periodic_timer, peer_check_expire, 0, 0);
-/* Exported for sysctl_net_ipv4. */
-int inet_peer_gc_mintime = 10 * HZ,
- inet_peer_gc_maxtime = 120 * HZ;
/* Called from ip_output.c:ip_init */
void __init inet_initpeers(void)
peer_cachep = kmem_cache_create("inet_peer_cache",
sizeof(struct inet_peer),
- 0, SLAB_HWCACHE_ALIGN|SLAB_PANIC,
- NULL, NULL);
+ 0, SLAB_HWCACHE_ALIGN | SLAB_PANIC,
+ NULL);
/* All the timers, started at system startup tend
to synchronize. Perturb it a bit.
/* Called with or without local BH being disabled. */
static void unlink_from_unused(struct inet_peer *p)
{
- spin_lock_bh(&inet_peer_unused_lock);
- if (p->unused_prevp != NULL) {
- /* On unused list. */
- *p->unused_prevp = p->unused_next;
- if (p->unused_next != NULL)
- p->unused_next->unused_prevp = p->unused_prevp;
- else
- inet_peer_unused_tailp = p->unused_prevp;
- p->unused_prevp = NULL; /* mark it as removed */
+ if (!list_empty(&p->unused)) {
+ spin_lock_bh(&unused_peers.lock);
+ list_del_init(&p->unused);
+ spin_unlock_bh(&unused_peers.lock);
}
- spin_unlock_bh(&inet_peer_unused_lock);
}
-/* Called with local BH disabled and the pool lock held. */
-#define lookup(daddr) \
+static int addr_compare(const struct inetpeer_addr *a,
+ const struct inetpeer_addr *b)
+{
+ int i, n = (a->family == AF_INET ? 1 : 4);
+
+ for (i = 0; i < n; i++) {
+ if (a->a6[i] == b->a6[i])
+ continue;
+ if (a->a6[i] < b->a6[i])
+ return -1;
+ return 1;
+ }
+
+ return 0;
+}
+
+/*
+ * Called with local BH disabled and the pool lock held.
+ */
+#define lookup(_daddr, _stack, _base) \
({ \
- struct inet_peer *u, **v; \
- stackptr = stack; \
- *stackptr++ = &peer_root; \
- for (u = peer_root; u != peer_avl_empty; ) { \
- if (daddr == u->v4daddr) \
+ struct inet_peer *u; \
+ struct inet_peer __rcu **v; \
+ \
+ stackptr = _stack; \
+ *stackptr++ = &_base->root; \
+ for (u = rcu_dereference_protected(_base->root, \
+ lockdep_is_held(&_base->lock)); \
+ u != peer_avl_empty; ) { \
+ int cmp = addr_compare(_daddr, &u->daddr); \
+ if (cmp == 0) \
break; \
- if (daddr < u->v4daddr) \
+ if (cmp == -1) \
v = &u->avl_left; \
else \
v = &u->avl_right; \
*stackptr++ = v; \
- u = *v; \
+ u = rcu_dereference_protected(*v, \
+ lockdep_is_held(&_base->lock)); \
} \
u; \
})
-/* Called with local BH disabled and the pool write lock held. */
-#define lookup_rightempty(start) \
+/*
+ * Called with rcu_read_lock_bh()
+ * Because we hold no lock against a writer, its quite possible we fall
+ * in an endless loop.
+ * But every pointer we follow is guaranteed to be valid thanks to RCU.
+ * We exit from this function if number of links exceeds PEER_MAXDEPTH
+ */
+static struct inet_peer *lookup_rcu_bh(const struct inetpeer_addr *daddr,
+ struct inet_peer_base *base)
+{
+ struct inet_peer *u = rcu_dereference_bh(base->root);
+ int count = 0;
+
+ while (u != peer_avl_empty) {
+ int cmp = addr_compare(daddr, &u->daddr);
+ if (cmp == 0) {
+ /* Before taking a reference, check if this entry was
+ * deleted, unlink_from_pool() sets refcnt=-1 to make
+ * distinction between an unused entry (refcnt=0) and
+ * a freed one.
+ */
+ if (unlikely(!atomic_add_unless(&u->refcnt, 1, -1)))
+ u = NULL;
+ return u;
+ }
+ if (cmp == -1)
+ u = rcu_dereference_bh(u->avl_left);
+ else
+ u = rcu_dereference_bh(u->avl_right);
+ if (unlikely(++count == PEER_MAXDEPTH))
+ break;
+ }
+ return NULL;
+}
+
+/* Called with local BH disabled and the pool lock held. */
+#define lookup_rightempty(start, base) \
({ \
- struct inet_peer *u, **v; \
+ struct inet_peer *u; \
+ struct inet_peer __rcu **v; \
*stackptr++ = &start->avl_left; \
v = &start->avl_left; \
- for (u = *v; u->avl_right != peer_avl_empty; ) { \
+ for (u = rcu_dereference_protected(*v, \
+ lockdep_is_held(&base->lock)); \
+ u->avl_right != peer_avl_empty_rcu; ) { \
v = &u->avl_right; \
*stackptr++ = v; \
- u = *v; \
+ u = rcu_dereference_protected(*v, \
+ lockdep_is_held(&base->lock)); \
} \
u; \
})
-/* Called with local BH disabled and the pool write lock held.
+/* Called with local BH disabled and the pool lock held.
* Variable names are the proof of operation correctness.
- * Look into mm/map_avl.c for more detail description of the ideas. */
-static void peer_avl_rebalance(struct inet_peer **stack[],
- struct inet_peer ***stackend)
+ * Look into mm/map_avl.c for more detail description of the ideas.
+ */
+static void peer_avl_rebalance(struct inet_peer __rcu **stack[],
+ struct inet_peer __rcu ***stackend,
+ struct inet_peer_base *base)
{
- struct inet_peer **nodep, *node, *l, *r;
+ struct inet_peer __rcu **nodep;
+ struct inet_peer *node, *l, *r;
int lh, rh;
while (stackend > stack) {
nodep = *--stackend;
- node = *nodep;
- l = node->avl_left;
- r = node->avl_right;
+ node = rcu_dereference_protected(*nodep,
+ lockdep_is_held(&base->lock));
+ l = rcu_dereference_protected(node->avl_left,
+ lockdep_is_held(&base->lock));
+ r = rcu_dereference_protected(node->avl_right,
+ lockdep_is_held(&base->lock));
lh = node_height(l);
rh = node_height(r);
if (lh > rh + 1) { /* l: RH+2 */
struct inet_peer *ll, *lr, *lrl, *lrr;
int lrh;
- ll = l->avl_left;
- lr = l->avl_right;
+ ll = rcu_dereference_protected(l->avl_left,
+ lockdep_is_held(&base->lock));
+ lr = rcu_dereference_protected(l->avl_right,
+ lockdep_is_held(&base->lock));
lrh = node_height(lr);
if (lrh <= node_height(ll)) { /* ll: RH+1 */
- node->avl_left = lr; /* lr: RH or RH+1 */
- node->avl_right = r; /* r: RH */
+ RCU_INIT_POINTER(node->avl_left, lr); /* lr: RH or RH+1 */
+ RCU_INIT_POINTER(node->avl_right, r); /* r: RH */
node->avl_height = lrh + 1; /* RH+1 or RH+2 */
- l->avl_left = ll; /* ll: RH+1 */
- l->avl_right = node; /* node: RH+1 or RH+2 */
+ RCU_INIT_POINTER(l->avl_left, ll); /* ll: RH+1 */
+ RCU_INIT_POINTER(l->avl_right, node); /* node: RH+1 or RH+2 */
l->avl_height = node->avl_height + 1;
- *nodep = l;
+ RCU_INIT_POINTER(*nodep, l);
} else { /* ll: RH, lr: RH+1 */
- lrl = lr->avl_left; /* lrl: RH or RH-1 */
- lrr = lr->avl_right; /* lrr: RH or RH-1 */
- node->avl_left = lrr; /* lrr: RH or RH-1 */
- node->avl_right = r; /* r: RH */
+ lrl = rcu_dereference_protected(lr->avl_left,
+ lockdep_is_held(&base->lock)); /* lrl: RH or RH-1 */
+ lrr = rcu_dereference_protected(lr->avl_right,
+ lockdep_is_held(&base->lock)); /* lrr: RH or RH-1 */
+ RCU_INIT_POINTER(node->avl_left, lrr); /* lrr: RH or RH-1 */
+ RCU_INIT_POINTER(node->avl_right, r); /* r: RH */
node->avl_height = rh + 1; /* node: RH+1 */
- l->avl_left = ll; /* ll: RH */
- l->avl_right = lrl; /* lrl: RH or RH-1 */
+ RCU_INIT_POINTER(l->avl_left, ll); /* ll: RH */
+ RCU_INIT_POINTER(l->avl_right, lrl); /* lrl: RH or RH-1 */
l->avl_height = rh + 1; /* l: RH+1 */
- lr->avl_left = l; /* l: RH+1 */
- lr->avl_right = node; /* node: RH+1 */
+ RCU_INIT_POINTER(lr->avl_left, l); /* l: RH+1 */
+ RCU_INIT_POINTER(lr->avl_right, node); /* node: RH+1 */
lr->avl_height = rh + 2;
- *nodep = lr;
+ RCU_INIT_POINTER(*nodep, lr);
}
} else if (rh > lh + 1) { /* r: LH+2 */
struct inet_peer *rr, *rl, *rlr, *rll;
int rlh;
- rr = r->avl_right;
- rl = r->avl_left;
+ rr = rcu_dereference_protected(r->avl_right,
+ lockdep_is_held(&base->lock));
+ rl = rcu_dereference_protected(r->avl_left,
+ lockdep_is_held(&base->lock));
rlh = node_height(rl);
if (rlh <= node_height(rr)) { /* rr: LH+1 */
- node->avl_right = rl; /* rl: LH or LH+1 */
- node->avl_left = l; /* l: LH */
+ RCU_INIT_POINTER(node->avl_right, rl); /* rl: LH or LH+1 */
+ RCU_INIT_POINTER(node->avl_left, l); /* l: LH */
node->avl_height = rlh + 1; /* LH+1 or LH+2 */
- r->avl_right = rr; /* rr: LH+1 */
- r->avl_left = node; /* node: LH+1 or LH+2 */
+ RCU_INIT_POINTER(r->avl_right, rr); /* rr: LH+1 */
+ RCU_INIT_POINTER(r->avl_left, node); /* node: LH+1 or LH+2 */
r->avl_height = node->avl_height + 1;
- *nodep = r;
+ RCU_INIT_POINTER(*nodep, r);
} else { /* rr: RH, rl: RH+1 */
- rlr = rl->avl_right; /* rlr: LH or LH-1 */
- rll = rl->avl_left; /* rll: LH or LH-1 */
- node->avl_right = rll; /* rll: LH or LH-1 */
- node->avl_left = l; /* l: LH */
+ rlr = rcu_dereference_protected(rl->avl_right,
+ lockdep_is_held(&base->lock)); /* rlr: LH or LH-1 */
+ rll = rcu_dereference_protected(rl->avl_left,
+ lockdep_is_held(&base->lock)); /* rll: LH or LH-1 */
+ RCU_INIT_POINTER(node->avl_right, rll); /* rll: LH or LH-1 */
+ RCU_INIT_POINTER(node->avl_left, l); /* l: LH */
node->avl_height = lh + 1; /* node: LH+1 */
- r->avl_right = rr; /* rr: LH */
- r->avl_left = rlr; /* rlr: LH or LH-1 */
+ RCU_INIT_POINTER(r->avl_right, rr); /* rr: LH */
+ RCU_INIT_POINTER(r->avl_left, rlr); /* rlr: LH or LH-1 */
r->avl_height = lh + 1; /* r: LH+1 */
- rl->avl_right = r; /* r: LH+1 */
- rl->avl_left = node; /* node: LH+1 */
+ RCU_INIT_POINTER(rl->avl_right, r); /* r: LH+1 */
+ RCU_INIT_POINTER(rl->avl_left, node); /* node: LH+1 */
rl->avl_height = lh + 2;
- *nodep = rl;
+ RCU_INIT_POINTER(*nodep, rl);
}
} else {
node->avl_height = (lh > rh ? lh : rh) + 1;
}
}
-/* Called with local BH disabled and the pool write lock held. */
-#define link_to_pool(n) \
+/* Called with local BH disabled and the pool lock held. */
+#define link_to_pool(n, base) \
do { \
n->avl_height = 1; \
- n->avl_left = peer_avl_empty; \
- n->avl_right = peer_avl_empty; \
- **--stackptr = n; \
- peer_avl_rebalance(stack, stackptr); \
-} while(0)
+ n->avl_left = peer_avl_empty_rcu; \
+ n->avl_right = peer_avl_empty_rcu; \
+ /* lockless readers can catch us now */ \
+ rcu_assign_pointer(**--stackptr, n); \
+ peer_avl_rebalance(stack, stackptr, base); \
+} while (0)
+
+static void inetpeer_free_rcu(struct rcu_head *head)
+{
+ kmem_cache_free(peer_cachep, container_of(head, struct inet_peer, rcu));
+}
/* May be called with local BH enabled. */
-static void unlink_from_pool(struct inet_peer *p)
+static void unlink_from_pool(struct inet_peer *p, struct inet_peer_base *base,
+ struct inet_peer __rcu **stack[PEER_MAXDEPTH])
{
int do_free;
do_free = 0;
- write_lock_bh(&peer_pool_lock);
+ spin_lock_bh(&base->lock);
/* Check the reference counter. It was artificially incremented by 1
- * in cleanup() function to prevent sudden disappearing. If the
- * reference count is still 1 then the node is referenced only as `p'
- * here and from the pool. So under the exclusive pool lock it's safe
- * to remove the node and free it later. */
- if (atomic_read(&p->refcnt) == 1) {
- struct inet_peer **stack[PEER_MAXDEPTH];
- struct inet_peer ***stackptr, ***delp;
- if (lookup(p->v4daddr) != p)
+ * in cleanup() function to prevent sudden disappearing. If we can
+ * atomically (because of lockless readers) take this last reference,
+ * it's safe to remove the node and free it later.
+ * We use refcnt=-1 to alert lockless readers this entry is deleted.
+ */
+ if (atomic_cmpxchg(&p->refcnt, 1, -1) == 1) {
+ struct inet_peer __rcu ***stackptr, ***delp;
+ if (lookup(&p->daddr, stack, base) != p)
BUG();
delp = stackptr - 1; /* *delp[0] == p */
- if (p->avl_left == peer_avl_empty) {
+ if (p->avl_left == peer_avl_empty_rcu) {
*delp[0] = p->avl_right;
--stackptr;
} else {
/* look for a node to insert instead of p */
struct inet_peer *t;
- t = lookup_rightempty(p);
- BUG_ON(*stackptr[-1] != t);
+ t = lookup_rightempty(p, base);
+ BUG_ON(rcu_dereference_protected(*stackptr[-1],
+ lockdep_is_held(&base->lock)) != t);
**--stackptr = t->avl_left;
- /* t is removed, t->v4daddr > x->v4daddr for any
+ /* t is removed, t->daddr > x->daddr for any
* x in p->avl_left subtree.
* Put t in the old place of p. */
- *delp[0] = t;
+ RCU_INIT_POINTER(*delp[0], t);
t->avl_left = p->avl_left;
t->avl_right = p->avl_right;
t->avl_height = p->avl_height;
BUG_ON(delp[1] != &p->avl_left);
delp[1] = &t->avl_left; /* was &p->avl_left */
}
- peer_avl_rebalance(stack, stackptr);
- peer_total--;
+ peer_avl_rebalance(stack, stackptr, base);
+ base->total--;
do_free = 1;
}
- write_unlock_bh(&peer_pool_lock);
+ spin_unlock_bh(&base->lock);
if (do_free)
- kmem_cache_free(peer_cachep, p);
+ call_rcu_bh(&p->rcu, inetpeer_free_rcu);
else
/* The node is used again. Decrease the reference counter
* back. The loop "cleanup -> unlink_from_unused
* -> unlink_from_pool -> putpeer -> link_to_unused
* -> cleanup (for the same node)"
* doesn't really exist because the entry will have a
- * recent deletion time and will not be cleaned again soon. */
+ * recent deletion time and will not be cleaned again soon.
+ */
inet_putpeer(p);
}
+static struct inet_peer_base *family_to_base(int family)
+{
+ return (family == AF_INET ? &v4_peers : &v6_peers);
+}
+
+static struct inet_peer_base *peer_to_base(struct inet_peer *p)
+{
+ return family_to_base(p->daddr.family);
+}
+
/* May be called with local BH enabled. */
-static int cleanup_once(unsigned long ttl)
+static int cleanup_once(unsigned long ttl, struct inet_peer __rcu **stack[PEER_MAXDEPTH])
{
- struct inet_peer *p;
+ struct inet_peer *p = NULL;
/* Remove the first entry from the list of unused nodes. */
- spin_lock_bh(&inet_peer_unused_lock);
- p = inet_peer_unused_head;
- if (p != NULL) {
- if (time_after(p->dtime + ttl, jiffies)) {
+ spin_lock_bh(&unused_peers.lock);
+ if (!list_empty(&unused_peers.list)) {
+ __u32 delta;
+
+ p = list_first_entry(&unused_peers.list, struct inet_peer, unused);
+ delta = (__u32)jiffies - p->dtime;
+
+ if (delta < ttl) {
/* Do not prune fresh entries. */
- spin_unlock_bh(&inet_peer_unused_lock);
+ spin_unlock_bh(&unused_peers.lock);
return -1;
}
- inet_peer_unused_head = p->unused_next;
- if (p->unused_next != NULL)
- p->unused_next->unused_prevp = p->unused_prevp;
- else
- inet_peer_unused_tailp = p->unused_prevp;
- p->unused_prevp = NULL; /* mark as not on the list */
+
+ list_del_init(&p->unused);
+
/* Grab an extra reference to prevent node disappearing
* before unlink_from_pool() call. */
atomic_inc(&p->refcnt);
}
- spin_unlock_bh(&inet_peer_unused_lock);
+ spin_unlock_bh(&unused_peers.lock);
if (p == NULL)
/* It means that the total number of USED entries has
* happen because of entry limits in route cache. */
return -1;
- unlink_from_pool(p);
+ unlink_from_pool(p, peer_to_base(p), stack);
return 0;
}
/* Called with or without local BH being disabled. */
-struct inet_peer *inet_getpeer(__u32 daddr, int create)
+struct inet_peer *inet_getpeer(struct inetpeer_addr *daddr, int create)
{
- struct inet_peer *p, *n;
- struct inet_peer **stack[PEER_MAXDEPTH], ***stackptr;
+ struct inet_peer __rcu **stack[PEER_MAXDEPTH], ***stackptr;
+ struct inet_peer_base *base = family_to_base(daddr->family);
+ struct inet_peer *p;
- /* Look up for the address quickly. */
- read_lock_bh(&peer_pool_lock);
- p = lookup(daddr);
- if (p != peer_avl_empty)
- atomic_inc(&p->refcnt);
- read_unlock_bh(&peer_pool_lock);
+ /* Look up for the address quickly, lockless.
+ * Because of a concurrent writer, we might not find an existing entry.
+ */
+ rcu_read_lock_bh();
+ p = lookup_rcu_bh(daddr, base);
+ rcu_read_unlock_bh();
+
+ if (p) {
+ /* The existing node has been found.
+ * Remove the entry from unused list if it was there.
+ */
+ unlink_from_unused(p);
+ return p;
+ }
+ /* retry an exact lookup, taking the lock before.
+ * At least, nodes should be hot in our cache.
+ */
+ spin_lock_bh(&base->lock);
+ p = lookup(daddr, stack, base);
if (p != peer_avl_empty) {
- /* The existing node has been found. */
+ atomic_inc(&p->refcnt);
+ spin_unlock_bh(&base->lock);
/* Remove the entry from unused list if it was there. */
unlink_from_unused(p);
return p;
}
+ p = create ? kmem_cache_alloc(peer_cachep, GFP_ATOMIC) : NULL;
+ if (p) {
+ p->daddr = *daddr;
+ atomic_set(&p->refcnt, 1);
+ atomic_set(&p->rid, 0);
+ atomic_set(&p->ip_id_count, secure_ip_id(daddr->a4));
+ p->tcp_ts_stamp = 0;
+ INIT_LIST_HEAD(&p->unused);
+
+
+ /* Link the node. */
+ link_to_pool(p, base);
+ base->total++;
+ }
+ spin_unlock_bh(&base->lock);
- if (!create)
- return NULL;
-
- /* Allocate the space outside the locked region. */
- n = kmem_cache_alloc(peer_cachep, GFP_ATOMIC);
- if (n == NULL)
- return NULL;
- n->v4daddr = daddr;
- atomic_set(&n->refcnt, 1);
- atomic_set(&n->rid, 0);
- n->ip_id_count = secure_ip_id(daddr);
- n->tcp_ts_stamp = 0;
-
- write_lock_bh(&peer_pool_lock);
- /* Check if an entry has suddenly appeared. */
- p = lookup(daddr);
- if (p != peer_avl_empty)
- goto out_free;
-
- /* Link the node. */
- link_to_pool(n);
- n->unused_prevp = NULL; /* not on the list */
- peer_total++;
- write_unlock_bh(&peer_pool_lock);
-
- if (peer_total >= inet_peer_threshold)
+ if (base->total >= inet_peer_threshold)
/* Remove one less-recently-used entry. */
- cleanup_once(0);
-
- return n;
-
-out_free:
- /* The appropriate node is already in the pool. */
- atomic_inc(&p->refcnt);
- write_unlock_bh(&peer_pool_lock);
- /* Remove the entry from unused list if it was there. */
- unlink_from_unused(p);
- /* Free preallocated the preallocated node. */
- kmem_cache_free(peer_cachep, n);
+ cleanup_once(0, stack);
+
return p;
}
+static int compute_total(void)
+{
+ return v4_peers.total + v6_peers.total;
+}
+EXPORT_SYMBOL_GPL(inet_getpeer);
+
/* Called with local BH disabled. */
static void peer_check_expire(unsigned long dummy)
{
- int i;
- int ttl;
+ unsigned long now = jiffies;
+ int ttl, total;
+ struct inet_peer __rcu **stack[PEER_MAXDEPTH];
- if (peer_total >= inet_peer_threshold)
+ total = compute_total();
+ if (total >= inet_peer_threshold)
ttl = inet_peer_minttl;
else
ttl = inet_peer_maxttl
- (inet_peer_maxttl - inet_peer_minttl) / HZ *
- peer_total / inet_peer_threshold * HZ;
- for (i = 0; i < PEER_MAX_CLEANUP_WORK && !cleanup_once(ttl); i++);
+ total / inet_peer_threshold * HZ;
+ while (!cleanup_once(ttl, stack)) {
+ if (jiffies != now)
+ break;
+ }
/* Trigger the timer after inet_peer_gc_mintime .. inet_peer_gc_maxtime
* interval depending on the total number of entries (more entries,
* less interval). */
- if (peer_total >= inet_peer_threshold)
+ total = compute_total();
+ if (total >= inet_peer_threshold)
peer_periodic_timer.expires = jiffies + inet_peer_gc_mintime;
else
peer_periodic_timer.expires = jiffies
+ inet_peer_gc_maxtime
- (inet_peer_gc_maxtime - inet_peer_gc_mintime) / HZ *
- peer_total / inet_peer_threshold * HZ;
+ total / inet_peer_threshold * HZ;
add_timer(&peer_periodic_timer);
}
+
+void inet_putpeer(struct inet_peer *p)
+{
+ local_bh_disable();
+
+ if (atomic_dec_and_lock(&p->refcnt, &unused_peers.lock)) {
+ list_add_tail(&p->unused, &unused_peers.list);
+ p->dtime = (__u32)jiffies;
+ spin_unlock(&unused_peers.lock);
+ }
+
+ local_bh_enable();
+}
+EXPORT_SYMBOL_GPL(inet_putpeer);
projects / linux-flexiantxendom0-natty.git / blobdiff