diff options
| -rw-r--r-- | net/ipv6/ip6_flowlabel.c | 34 |
1 files changed, 25 insertions, 9 deletions
diff --git a/net/ipv6/ip6_flowlabel.c b/net/ipv6/ip6_flowlabel.c index f40a08669db0..e55ae1a1f560 100644 --- a/net/ipv6/ip6_flowlabel.c +++ b/net/ipv6/ip6_flowlabel.c @@ -154,8 +154,10 @@ static void ip6_fl_gc(unsigned long dummy) write_unlock(&ip6_fl_lock); } -static int fl_intern(struct ip6_flowlabel *fl, __be32 label) +static struct ip6_flowlabel *fl_intern(struct ip6_flowlabel *fl, __be32 label) { + struct ip6_flowlabel *lfl; + fl->label = label & IPV6_FLOWLABEL_MASK; write_lock_bh(&ip6_fl_lock); @@ -163,12 +165,26 @@ static int fl_intern(struct ip6_flowlabel *fl, __be32 label) for (;;) { fl->label = htonl(net_random())&IPV6_FLOWLABEL_MASK; if (fl->label) { - struct ip6_flowlabel *lfl; lfl = __fl_lookup(fl->label); if (lfl == NULL) break; } } + } else { + /* + * we dropper the ip6_fl_lock, so this entry could reappear + * and we need to recheck with it. + * + * OTOH no need to search the active socket first, like it is + * done in ipv6_flowlabel_opt - sock is locked, so new entry + * with the same label can only appear on another sock + */ + lfl = __fl_lookup(fl->label); + if (lfl != NULL) { + atomic_inc(&lfl->users); + write_unlock_bh(&ip6_fl_lock); + return lfl; + } } fl->lastuse = jiffies; @@ -176,7 +192,7 @@ static int fl_intern(struct ip6_flowlabel *fl, __be32 label) fl_ht[FL_HASH(fl->label)] = fl; atomic_inc(&fl_size); write_unlock_bh(&ip6_fl_lock); - return 0; + return NULL; } @@ -429,7 +445,8 @@ int ipv6_flowlabel_opt(struct sock *sk, char __user *optval, int optlen) struct in6_flowlabel_req freq; struct ipv6_fl_socklist *sfl1=NULL; struct ipv6_fl_socklist *sfl, **sflp; - struct ip6_flowlabel *fl; + struct ip6_flowlabel *fl, *fl1 = NULL; + if (optlen < sizeof(freq)) return -EINVAL; @@ -485,8 +502,6 @@ int ipv6_flowlabel_opt(struct sock *sk, char __user *optval, int optlen) sfl1 = kmalloc(sizeof(*sfl1), GFP_KERNEL); if (freq.flr_label) { - struct ip6_flowlabel *fl1 = NULL; - err = -EEXIST; read_lock_bh(&ip6_sk_fl_lock); for (sfl = np->ipv6_fl_list; sfl; sfl = sfl->next) { @@ -505,6 +520,7 @@ int ipv6_flowlabel_opt(struct sock *sk, char __user *optval, int optlen) if (fl1 == NULL) fl1 = fl_lookup(freq.flr_label); if (fl1) { +recheck: err = -EEXIST; if (freq.flr_flags&IPV6_FL_F_EXCL) goto release; @@ -543,9 +559,9 @@ release: if (sfl1 == NULL || (err = mem_check(sk)) != 0) goto done; - err = fl_intern(fl, freq.flr_label); - if (err) - goto done; + fl1 = fl_intern(fl, freq.flr_label); + if (fl1 != NULL) + goto recheck; if (!freq.flr_label) { if (copy_to_user(&((struct in6_flowlabel_req __user *) optval)->flr_label, |