diff options
| -rw-r--r-- | include/net/inetpeer.h | 2 | ||||
| -rw-r--r-- | net/ipv4/inetpeer.c | 138 |
2 files changed, 81 insertions, 59 deletions
diff --git a/include/net/inetpeer.h b/include/net/inetpeer.h index 417d0c894f29..fe239bfe5f7f 100644 --- a/include/net/inetpeer.h +++ b/include/net/inetpeer.h @@ -15,7 +15,7 @@ struct inet_peer { /* group together avl_left,avl_right,v4daddr to speedup lookups */ - struct inet_peer *avl_left, *avl_right; + struct inet_peer __rcu *avl_left, *avl_right; __be32 v4daddr; /* peer's address */ __u32 avl_height; struct list_head unused; diff --git a/net/ipv4/inetpeer.c b/net/ipv4/inetpeer.c index 9ffa24b9a804..9e94d7cf4f8a 100644 --- a/net/ipv4/inetpeer.c +++ b/net/ipv4/inetpeer.c @@ -72,18 +72,19 @@ static struct kmem_cache *peer_cachep __read_mostly; #define node_height(x) x->avl_height #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, - .avl_right = peer_avl_empty, + .avl_left = peer_avl_empty_rcu, + .avl_right = peer_avl_empty_rcu, .avl_height = 0 }; static struct { - struct inet_peer *root; + struct inet_peer __rcu *root; spinlock_t lock; int total; } peers = { - .root = peer_avl_empty, + .root = peer_avl_empty_rcu, .lock = __SPIN_LOCK_UNLOCKED(peers.lock), .total = 0, }; @@ -156,11 +157,14 @@ static void unlink_from_unused(struct inet_peer *p) */ #define lookup(_daddr, _stack) \ ({ \ - struct inet_peer *u, **v; \ + struct inet_peer *u; \ + struct inet_peer __rcu **v; \ \ stackptr = _stack; \ *stackptr++ = &peers.root; \ - for (u = peers.root; u != peer_avl_empty; ) { \ + for (u = rcu_dereference_protected(peers.root, \ + lockdep_is_held(&peers.lock)); \ + u != peer_avl_empty; ) { \ if (_daddr == u->v4daddr) \ break; \ if ((__force __u32)_daddr < (__force __u32)u->v4daddr) \ @@ -168,7 +172,8 @@ static void unlink_from_unused(struct inet_peer *p) else \ v = &u->avl_right; \ *stackptr++ = v; \ - u = *v; \ + u = rcu_dereference_protected(*v, \ + lockdep_is_held(&peers.lock)); \ } \ u; \ }) @@ -209,13 +214,17 @@ static struct inet_peer *lookup_rcu_bh(__be32 daddr) /* Called with local BH disabled and the pool lock held. */ #define lookup_rightempty(start) \ ({ \ - 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(&peers.lock)); \ + u->avl_right != peer_avl_empty_rcu; ) { \ v = &u->avl_right; \ *stackptr++ = v; \ - u = *v; \ + u = rcu_dereference_protected(*v, \ + lockdep_is_held(&peers.lock)); \ } \ u; \ }) @@ -224,74 +233,86 @@ static struct inet_peer *lookup_rcu_bh(__be32 daddr) * 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) +static void peer_avl_rebalance(struct inet_peer __rcu **stack[], + struct inet_peer __rcu ***stackend) { - 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(&peers.lock)); + l = rcu_dereference_protected(node->avl_left, + lockdep_is_held(&peers.lock)); + r = rcu_dereference_protected(node->avl_right, + lockdep_is_held(&peers.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(&peers.lock)); + lr = rcu_dereference_protected(l->avl_right, + lockdep_is_held(&peers.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(&peers.lock)); /* lrl: RH or RH-1 */ + lrr = rcu_dereference_protected(lr->avl_right, + lockdep_is_held(&peers.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(&peers.lock)); + rl = rcu_dereference_protected(r->avl_left, + lockdep_is_held(&peers.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(&peers.lock)); /* rlr: LH or LH-1 */ + rll = rcu_dereference_protected(rl->avl_left, + lockdep_is_held(&peers.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; @@ -303,10 +324,10 @@ static void peer_avl_rebalance(struct inet_peer **stack[], #define link_to_pool(n) \ do { \ n->avl_height = 1; \ - n->avl_left = peer_avl_empty; \ - n->avl_right = peer_avl_empty; \ - smp_wmb(); /* lockless readers can catch us now */ \ - **--stackptr = n; \ + 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); \ } while (0) @@ -330,24 +351,25 @@ static void unlink_from_pool(struct inet_peer *p) * We use refcnt=-1 to alert lockless readers this entry is deleted. */ if (atomic_cmpxchg(&p->refcnt, 1, -1) == 1) { - struct inet_peer **stack[PEER_MAXDEPTH]; - struct inet_peer ***stackptr, ***delp; + struct inet_peer __rcu **stack[PEER_MAXDEPTH]; + struct inet_peer __rcu ***stackptr, ***delp; if (lookup(p->v4daddr, stack) != 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); + BUG_ON(rcu_dereference_protected(*stackptr[-1], + lockdep_is_held(&peers.lock)) != t); **--stackptr = t->avl_left; /* t is removed, t->v4daddr > x->v4daddr 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; @@ -414,7 +436,7 @@ static int cleanup_once(unsigned long ttl) struct inet_peer *inet_getpeer(__be32 daddr, int create) { struct inet_peer *p; - struct inet_peer **stack[PEER_MAXDEPTH], ***stackptr; + struct inet_peer __rcu **stack[PEER_MAXDEPTH], ***stackptr; /* Look up for the address quickly, lockless. * Because of a concurrent writer, we might not find an existing entry. |