From d3aedd5ebd4b0b925b0bcda548066803e1318499 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?YOSHIFUJI=20Hideaki=20/=20=E5=90=89=E8=97=A4=E8=8B=B1?= =?UTF-8?q?=E6=98=8E?= Date: Wed, 30 Jan 2013 09:27:47 +0000 Subject: [PATCH] ipv6 flowlabel: Convert hash list to RCU. Signed-off-by: YOSHIFUJI Hideaki Signed-off-by: David S. Miller --- include/net/ipv6.h | 1 + net/ipv6/ip6_flowlabel.c | 94 +++++++++++++++++++++++----------------- 2 files changed, 55 insertions(+), 40 deletions(-) diff --git a/include/net/ipv6.h b/include/net/ipv6.h index dc30b60975ef..1d457161def2 100644 --- a/include/net/ipv6.h +++ b/include/net/ipv6.h @@ -222,6 +222,7 @@ struct ip6_flowlabel { struct in6_addr dst; struct ipv6_txoptions *opt; unsigned long linger; + struct rcu_head rcu; u8 share; union { struct pid *pid; diff --git a/net/ipv6/ip6_flowlabel.c b/net/ipv6/ip6_flowlabel.c index 5d767f1b8780..da156015d827 100644 --- a/net/ipv6/ip6_flowlabel.c +++ b/net/ipv6/ip6_flowlabel.c @@ -51,25 +51,33 @@ #define FL_HASH(l) (ntohl(l)&FL_HASH_MASK) static atomic_t fl_size = ATOMIC_INIT(0); -static struct ip6_flowlabel *fl_ht[FL_HASH_MASK+1]; +static struct ip6_flowlabel __rcu *fl_ht[FL_HASH_MASK+1]; static void ip6_fl_gc(unsigned long dummy); static DEFINE_TIMER(ip6_fl_gc_timer, ip6_fl_gc, 0, 0); /* FL hash table lock: it protects only of GC */ -static DEFINE_RWLOCK(ip6_fl_lock); +static DEFINE_SPINLOCK(ip6_fl_lock); /* Big socket sock */ static DEFINE_RWLOCK(ip6_sk_fl_lock); +#define for_each_fl_rcu(hash, fl) \ + for (fl = rcu_dereference(fl_ht[(hash)]); \ + fl != NULL; \ + fl = rcu_dereference(fl->next)) +#define for_each_fl_continue_rcu(fl) \ + for (fl = rcu_dereference(fl->next); \ + fl != NULL; \ + fl = rcu_dereference(fl->next)) static inline struct ip6_flowlabel *__fl_lookup(struct net *net, __be32 label) { struct ip6_flowlabel *fl; - for (fl=fl_ht[FL_HASH(label)]; fl; fl = fl->next) { + for_each_fl_rcu(FL_HASH(label), fl) { if (fl->label == label && net_eq(fl->fl_net, net)) return fl; } @@ -80,11 +88,11 @@ static struct ip6_flowlabel *fl_lookup(struct net *net, __be32 label) { struct ip6_flowlabel *fl; - read_lock_bh(&ip6_fl_lock); + rcu_read_lock_bh(); fl = __fl_lookup(net, label); - if (fl) - atomic_inc(&fl->users); - read_unlock_bh(&ip6_fl_lock); + if (fl && !atomic_inc_not_zero(&fl->users)) + fl = NULL; + rcu_read_unlock_bh(); return fl; } @@ -96,13 +104,13 @@ static void fl_free(struct ip6_flowlabel *fl) put_pid(fl->owner.pid); release_net(fl->fl_net); kfree(fl->opt); + kfree_rcu(fl, rcu); } - kfree(fl); } static void fl_release(struct ip6_flowlabel *fl) { - write_lock_bh(&ip6_fl_lock); + spin_lock_bh(&ip6_fl_lock); fl->lastuse = jiffies; if (atomic_dec_and_test(&fl->users)) { @@ -119,7 +127,7 @@ static void fl_release(struct ip6_flowlabel *fl) time_after(ip6_fl_gc_timer.expires, ttd)) mod_timer(&ip6_fl_gc_timer, ttd); } - write_unlock_bh(&ip6_fl_lock); + spin_unlock_bh(&ip6_fl_lock); } static void ip6_fl_gc(unsigned long dummy) @@ -128,12 +136,13 @@ static void ip6_fl_gc(unsigned long dummy) unsigned long now = jiffies; unsigned long sched = 0; - write_lock(&ip6_fl_lock); + spin_lock(&ip6_fl_lock); for (i=0; i<=FL_HASH_MASK; i++) { struct ip6_flowlabel *fl, **flp; flp = &fl_ht[i]; - while ((fl=*flp) != NULL) { + while ((fl = rcu_dereference_protected(*flp, + lockdep_is_held(&ip6_fl_lock))) != NULL) { if (atomic_read(&fl->users) == 0) { unsigned long ttd = fl->lastuse + fl->linger; if (time_after(ttd, fl->expires)) @@ -156,18 +165,19 @@ static void ip6_fl_gc(unsigned long dummy) if (sched) { mod_timer(&ip6_fl_gc_timer, sched); } - write_unlock(&ip6_fl_lock); + spin_unlock(&ip6_fl_lock); } static void __net_exit ip6_fl_purge(struct net *net) { int i; - write_lock(&ip6_fl_lock); + spin_lock(&ip6_fl_lock); for (i = 0; i <= FL_HASH_MASK; i++) { struct ip6_flowlabel *fl, **flp; flp = &fl_ht[i]; - while ((fl = *flp) != NULL) { + while ((fl = rcu_dereference_protected(*flp, + lockdep_is_held(&ip6_fl_lock))) != NULL) { if (net_eq(fl->fl_net, net) && atomic_read(&fl->users) == 0) { *flp = fl->next; @@ -178,7 +188,7 @@ static void __net_exit ip6_fl_purge(struct net *net) flp = &fl->next; } } - write_unlock(&ip6_fl_lock); + spin_unlock(&ip6_fl_lock); } static struct ip6_flowlabel *fl_intern(struct net *net, @@ -188,7 +198,7 @@ static struct ip6_flowlabel *fl_intern(struct net *net, fl->label = label & IPV6_FLOWLABEL_MASK; - write_lock_bh(&ip6_fl_lock); + spin_lock_bh(&ip6_fl_lock); if (label == 0) { for (;;) { fl->label = htonl(net_random())&IPV6_FLOWLABEL_MASK; @@ -210,16 +220,16 @@ static struct ip6_flowlabel *fl_intern(struct net *net, lfl = __fl_lookup(net, fl->label); if (lfl != NULL) { atomic_inc(&lfl->users); - write_unlock_bh(&ip6_fl_lock); + spin_unlock_bh(&ip6_fl_lock); return lfl; } } fl->lastuse = jiffies; fl->next = fl_ht[FL_HASH(fl->label)]; - fl_ht[FL_HASH(fl->label)] = fl; + rcu_assign_pointer(fl_ht[FL_HASH(fl->label)], fl); atomic_inc(&fl_size); - write_unlock_bh(&ip6_fl_lock); + spin_unlock_bh(&ip6_fl_lock); return NULL; } @@ -650,13 +660,13 @@ static struct ip6_flowlabel *ip6fl_get_first(struct seq_file *seq) struct net *net = seq_file_net(seq); for (state->bucket = 0; state->bucket <= FL_HASH_MASK; ++state->bucket) { - fl = fl_ht[state->bucket]; - - while (fl && !net_eq(fl->fl_net, net)) - fl = fl->next; - if (fl) - break; + for_each_fl_rcu(state->bucket, fl) { + if (net_eq(fl->fl_net, net)) + goto out; + } } + fl = NULL; +out: return fl; } @@ -665,18 +675,22 @@ static struct ip6_flowlabel *ip6fl_get_next(struct seq_file *seq, struct ip6_flo struct ip6fl_iter_state *state = ip6fl_seq_private(seq); struct net *net = seq_file_net(seq); - fl = fl->next; + for_each_fl_continue_rcu(fl) { + if (net_eq(fl->fl_net, net)) + goto out; + } + try_again: - while (fl && !net_eq(fl->fl_net, net)) - fl = fl->next; - - while (!fl) { - if (++state->bucket <= FL_HASH_MASK) { - fl = fl_ht[state->bucket]; - goto try_again; - } else - break; + if (++state->bucket <= FL_HASH_MASK) { + for_each_fl_rcu(state->bucket, fl) { + if (net_eq(fl->fl_net, net)) + goto out; + } + goto try_again; } + fl = NULL; + +out: return fl; } @@ -690,9 +704,9 @@ static struct ip6_flowlabel *ip6fl_get_idx(struct seq_file *seq, loff_t pos) } static void *ip6fl_seq_start(struct seq_file *seq, loff_t *pos) - __acquires(ip6_fl_lock) + __acquires(RCU) { - read_lock_bh(&ip6_fl_lock); + rcu_read_lock_bh(); return *pos ? ip6fl_get_idx(seq, *pos - 1) : SEQ_START_TOKEN; } @@ -709,9 +723,9 @@ static void *ip6fl_seq_next(struct seq_file *seq, void *v, loff_t *pos) } static void ip6fl_seq_stop(struct seq_file *seq, void *v) - __releases(ip6_fl_lock) + __releases(RCU) { - read_unlock_bh(&ip6_fl_lock); + rcu_read_unlock_bh(); } static int ip6fl_seq_show(struct seq_file *seq, void *v) -- GitLab