inetpeer: Abstract out the tree root accesses.
Instead of directly accessing "peer", change to code to operate using a "struct inet_peer_base *" pointer. This will facilitate the addition of a seperate tree for ipv6 peer entries. Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David S. Miller
parent
c20ec76157
commit
98158f5a85
1 changed files with 69 additions and 50 deletions
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@ -79,13 +79,13 @@ static const struct inet_peer peer_fake_node = {
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.avl_height = 0
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};
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static struct {
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static struct inet_peer_base {
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struct inet_peer __rcu *root;
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spinlock_t lock;
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int total;
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} peers = {
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} v4_peers = {
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.root = peer_avl_empty_rcu,
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.lock = __SPIN_LOCK_UNLOCKED(peers.lock),
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.lock = __SPIN_LOCK_UNLOCKED(v4_peers.lock),
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.total = 0,
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};
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#define PEER_MAXDEPTH 40 /* sufficient for about 2^27 nodes */
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@ -155,15 +155,15 @@ static void unlink_from_unused(struct inet_peer *p)
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/*
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* Called with local BH disabled and the pool lock held.
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*/
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#define lookup(_daddr, _stack) \
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#define lookup(_daddr, _stack, _base) \
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({ \
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struct inet_peer *u; \
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struct inet_peer __rcu **v; \
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\
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stackptr = _stack; \
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*stackptr++ = &peers.root; \
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for (u = rcu_dereference_protected(peers.root, \
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lockdep_is_held(&peers.lock)); \
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*stackptr++ = &_base->root; \
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for (u = rcu_dereference_protected(_base->root, \
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lockdep_is_held(&_base->lock)); \
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u != peer_avl_empty; ) { \
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if (_daddr == u->v4daddr) \
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break; \
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@ -173,7 +173,7 @@ static void unlink_from_unused(struct inet_peer *p)
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v = &u->avl_right; \
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*stackptr++ = v; \
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u = rcu_dereference_protected(*v, \
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lockdep_is_held(&peers.lock)); \
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lockdep_is_held(&_base->lock)); \
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} \
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u; \
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})
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@ -185,9 +185,9 @@ static void unlink_from_unused(struct inet_peer *p)
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* But every pointer we follow is guaranteed to be valid thanks to RCU.
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* We exit from this function if number of links exceeds PEER_MAXDEPTH
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*/
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static struct inet_peer *lookup_rcu_bh(__be32 daddr)
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static struct inet_peer *lookup_rcu_bh(__be32 daddr, struct inet_peer_base *base)
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{
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struct inet_peer *u = rcu_dereference_bh(peers.root);
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struct inet_peer *u = rcu_dereference_bh(base->root);
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int count = 0;
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while (u != peer_avl_empty) {
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@ -212,19 +212,19 @@ static struct inet_peer *lookup_rcu_bh(__be32 daddr)
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}
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/* Called with local BH disabled and the pool lock held. */
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#define lookup_rightempty(start) \
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#define lookup_rightempty(start, base) \
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({ \
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struct inet_peer *u; \
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struct inet_peer __rcu **v; \
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*stackptr++ = &start->avl_left; \
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v = &start->avl_left; \
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for (u = rcu_dereference_protected(*v, \
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lockdep_is_held(&peers.lock)); \
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lockdep_is_held(&base->lock)); \
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u->avl_right != peer_avl_empty_rcu; ) { \
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v = &u->avl_right; \
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*stackptr++ = v; \
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u = rcu_dereference_protected(*v, \
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lockdep_is_held(&peers.lock)); \
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lockdep_is_held(&base->lock)); \
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} \
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u; \
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})
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@ -234,7 +234,8 @@ static struct inet_peer *lookup_rcu_bh(__be32 daddr)
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* Look into mm/map_avl.c for more detail description of the ideas.
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*/
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static void peer_avl_rebalance(struct inet_peer __rcu **stack[],
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struct inet_peer __rcu ***stackend)
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struct inet_peer __rcu ***stackend,
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struct inet_peer_base *base)
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{
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struct inet_peer __rcu **nodep;
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struct inet_peer *node, *l, *r;
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@ -243,20 +244,20 @@ static void peer_avl_rebalance(struct inet_peer __rcu **stack[],
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while (stackend > stack) {
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nodep = *--stackend;
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node = rcu_dereference_protected(*nodep,
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lockdep_is_held(&peers.lock));
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lockdep_is_held(&base->lock));
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l = rcu_dereference_protected(node->avl_left,
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lockdep_is_held(&peers.lock));
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lockdep_is_held(&base->lock));
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r = rcu_dereference_protected(node->avl_right,
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lockdep_is_held(&peers.lock));
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lockdep_is_held(&base->lock));
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lh = node_height(l);
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rh = node_height(r);
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if (lh > rh + 1) { /* l: RH+2 */
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struct inet_peer *ll, *lr, *lrl, *lrr;
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int lrh;
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ll = rcu_dereference_protected(l->avl_left,
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lockdep_is_held(&peers.lock));
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lockdep_is_held(&base->lock));
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lr = rcu_dereference_protected(l->avl_right,
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lockdep_is_held(&peers.lock));
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lockdep_is_held(&base->lock));
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lrh = node_height(lr);
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if (lrh <= node_height(ll)) { /* ll: RH+1 */
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RCU_INIT_POINTER(node->avl_left, lr); /* lr: RH or RH+1 */
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@ -268,9 +269,9 @@ static void peer_avl_rebalance(struct inet_peer __rcu **stack[],
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RCU_INIT_POINTER(*nodep, l);
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} else { /* ll: RH, lr: RH+1 */
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lrl = rcu_dereference_protected(lr->avl_left,
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lockdep_is_held(&peers.lock)); /* lrl: RH or RH-1 */
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lockdep_is_held(&base->lock)); /* lrl: RH or RH-1 */
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lrr = rcu_dereference_protected(lr->avl_right,
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lockdep_is_held(&peers.lock)); /* lrr: RH or RH-1 */
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lockdep_is_held(&base->lock)); /* lrr: RH or RH-1 */
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RCU_INIT_POINTER(node->avl_left, lrr); /* lrr: RH or RH-1 */
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RCU_INIT_POINTER(node->avl_right, r); /* r: RH */
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node->avl_height = rh + 1; /* node: RH+1 */
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@ -286,9 +287,9 @@ static void peer_avl_rebalance(struct inet_peer __rcu **stack[],
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struct inet_peer *rr, *rl, *rlr, *rll;
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int rlh;
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rr = rcu_dereference_protected(r->avl_right,
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lockdep_is_held(&peers.lock));
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lockdep_is_held(&base->lock));
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rl = rcu_dereference_protected(r->avl_left,
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lockdep_is_held(&peers.lock));
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lockdep_is_held(&base->lock));
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rlh = node_height(rl);
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if (rlh <= node_height(rr)) { /* rr: LH+1 */
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RCU_INIT_POINTER(node->avl_right, rl); /* rl: LH or LH+1 */
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@ -300,9 +301,9 @@ static void peer_avl_rebalance(struct inet_peer __rcu **stack[],
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RCU_INIT_POINTER(*nodep, r);
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} else { /* rr: RH, rl: RH+1 */
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rlr = rcu_dereference_protected(rl->avl_right,
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lockdep_is_held(&peers.lock)); /* rlr: LH or LH-1 */
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lockdep_is_held(&base->lock)); /* rlr: LH or LH-1 */
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rll = rcu_dereference_protected(rl->avl_left,
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lockdep_is_held(&peers.lock)); /* rll: LH or LH-1 */
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lockdep_is_held(&base->lock)); /* rll: LH or LH-1 */
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RCU_INIT_POINTER(node->avl_right, rll); /* rll: LH or LH-1 */
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RCU_INIT_POINTER(node->avl_left, l); /* l: LH */
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node->avl_height = lh + 1; /* node: LH+1 */
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@ -321,14 +322,14 @@ static void peer_avl_rebalance(struct inet_peer __rcu **stack[],
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}
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/* Called with local BH disabled and the pool lock held. */
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#define link_to_pool(n) \
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#define link_to_pool(n, base) \
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do { \
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n->avl_height = 1; \
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n->avl_left = peer_avl_empty_rcu; \
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n->avl_right = peer_avl_empty_rcu; \
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/* lockless readers can catch us now */ \
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rcu_assign_pointer(**--stackptr, n); \
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peer_avl_rebalance(stack, stackptr); \
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peer_avl_rebalance(stack, stackptr, base); \
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} while (0)
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static void inetpeer_free_rcu(struct rcu_head *head)
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@ -337,13 +338,13 @@ static void inetpeer_free_rcu(struct rcu_head *head)
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}
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/* May be called with local BH enabled. */
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static void unlink_from_pool(struct inet_peer *p)
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static void unlink_from_pool(struct inet_peer *p, struct inet_peer_base *base)
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{
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int do_free;
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do_free = 0;
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spin_lock_bh(&peers.lock);
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spin_lock_bh(&base->lock);
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/* Check the reference counter. It was artificially incremented by 1
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* in cleanup() function to prevent sudden disappearing. If we can
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* atomically (because of lockless readers) take this last reference,
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@ -353,7 +354,7 @@ static void unlink_from_pool(struct inet_peer *p)
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if (atomic_cmpxchg(&p->refcnt, 1, -1) == 1) {
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struct inet_peer __rcu **stack[PEER_MAXDEPTH];
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struct inet_peer __rcu ***stackptr, ***delp;
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if (lookup(p->v4daddr, stack) != p)
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if (lookup(p->v4daddr, stack, base) != p)
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BUG();
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delp = stackptr - 1; /* *delp[0] == p */
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if (p->avl_left == peer_avl_empty_rcu) {
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@ -362,9 +363,9 @@ static void unlink_from_pool(struct inet_peer *p)
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} else {
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/* look for a node to insert instead of p */
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struct inet_peer *t;
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t = lookup_rightempty(p);
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t = lookup_rightempty(p, base);
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BUG_ON(rcu_dereference_protected(*stackptr[-1],
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lockdep_is_held(&peers.lock)) != t);
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lockdep_is_held(&base->lock)) != t);
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**--stackptr = t->avl_left;
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/* t is removed, t->v4daddr > x->v4daddr for any
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* x in p->avl_left subtree.
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@ -376,11 +377,11 @@ static void unlink_from_pool(struct inet_peer *p)
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BUG_ON(delp[1] != &p->avl_left);
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delp[1] = &t->avl_left; /* was &p->avl_left */
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}
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peer_avl_rebalance(stack, stackptr);
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peers.total--;
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peer_avl_rebalance(stack, stackptr, base);
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base->total--;
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do_free = 1;
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}
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spin_unlock_bh(&peers.lock);
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spin_unlock_bh(&base->lock);
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if (do_free)
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call_rcu_bh(&p->rcu, inetpeer_free_rcu);
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@ -395,6 +396,11 @@ static void unlink_from_pool(struct inet_peer *p)
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inet_putpeer(p);
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}
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static struct inet_peer_base *peer_to_base(struct inet_peer *p)
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{
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return &v4_peers;
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}
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/* May be called with local BH enabled. */
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static int cleanup_once(unsigned long ttl)
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{
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@ -428,21 +434,27 @@ static int cleanup_once(unsigned long ttl)
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* happen because of entry limits in route cache. */
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return -1;
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unlink_from_pool(p);
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unlink_from_pool(p, peer_to_base(p));
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return 0;
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}
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static struct inet_peer_base *family_to_base(int family)
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{
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return &v4_peers;
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}
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/* Called with or without local BH being disabled. */
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struct inet_peer *inet_getpeer(__be32 daddr, int create)
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{
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struct inet_peer *p;
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struct inet_peer __rcu **stack[PEER_MAXDEPTH], ***stackptr;
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struct inet_peer_base *base = family_to_base(AF_INET);
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struct inet_peer *p;
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/* Look up for the address quickly, lockless.
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* Because of a concurrent writer, we might not find an existing entry.
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*/
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rcu_read_lock_bh();
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p = lookup_rcu_bh(daddr);
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p = lookup_rcu_bh(daddr, base);
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rcu_read_unlock_bh();
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if (p) {
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@ -456,11 +468,11 @@ struct inet_peer *inet_getpeer(__be32 daddr, int create)
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/* retry an exact lookup, taking the lock before.
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* At least, nodes should be hot in our cache.
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*/
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spin_lock_bh(&peers.lock);
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p = lookup(daddr, stack);
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spin_lock_bh(&base->lock);
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p = lookup(daddr, stack, base);
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if (p != peer_avl_empty) {
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atomic_inc(&p->refcnt);
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spin_unlock_bh(&peers.lock);
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spin_unlock_bh(&base->lock);
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/* Remove the entry from unused list if it was there. */
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unlink_from_unused(p);
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return p;
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@ -476,30 +488,36 @@ struct inet_peer *inet_getpeer(__be32 daddr, int create)
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/* Link the node. */
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link_to_pool(p);
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peers.total++;
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link_to_pool(p, base);
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base->total++;
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}
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spin_unlock_bh(&peers.lock);
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spin_unlock_bh(&base->lock);
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if (peers.total >= inet_peer_threshold)
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if (base->total >= inet_peer_threshold)
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/* Remove one less-recently-used entry. */
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cleanup_once(0);
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return p;
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}
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static int compute_total(void)
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{
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return v4_peers.total;
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}
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/* Called with local BH disabled. */
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static void peer_check_expire(unsigned long dummy)
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{
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unsigned long now = jiffies;
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int ttl;
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int ttl, total;
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if (peers.total >= inet_peer_threshold)
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total = compute_total();
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if (total >= inet_peer_threshold)
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ttl = inet_peer_minttl;
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else
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ttl = inet_peer_maxttl
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- (inet_peer_maxttl - inet_peer_minttl) / HZ *
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peers.total / inet_peer_threshold * HZ;
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total / inet_peer_threshold * HZ;
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while (!cleanup_once(ttl)) {
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if (jiffies != now)
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break;
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@ -508,13 +526,14 @@ static void peer_check_expire(unsigned long dummy)
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/* Trigger the timer after inet_peer_gc_mintime .. inet_peer_gc_maxtime
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* interval depending on the total number of entries (more entries,
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* less interval). */
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if (peers.total >= inet_peer_threshold)
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total = compute_total();
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if (total >= inet_peer_threshold)
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peer_periodic_timer.expires = jiffies + inet_peer_gc_mintime;
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else
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peer_periodic_timer.expires = jiffies
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+ inet_peer_gc_maxtime
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- (inet_peer_gc_maxtime - inet_peer_gc_mintime) / HZ *
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peers.total / inet_peer_threshold * HZ;
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total / inet_peer_threshold * HZ;
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add_timer(&peer_periodic_timer);
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}
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