ipv6: addrconf: cleanup locking in ipv6_add_addr
ipv6_add_addr is called in process context with rtnl lock held (e.g., manual config of an address) or during softirq processing (e.g., autoconf and address from a router advertisement). Currently, ipv6_add_addr calls rcu_read_lock_bh shortly after entry and does not call unlock until exit, minus the call around the address validator notifier. Similarly, addrconf_hash_lock is taken after the validator notifier and held until exit. This forces the allocation of inet6_ifaddr to always be atomic. Refactor ipv6_add_addr as follows: 1. add an input boolean to discriminate the call path (process context or softirq). This new flag controls whether the alloc can be done with GFP_KERNEL or GFP_ATOMIC. 2. Move the rcu_read_lock_bh and unlock calls only around functions that do rcu updates. 3. Remove the in6_dev_hold and put added by3ad7d2468f("Ipvlan should return an error when an address is already in use."). This was done presumably because rcu_read_unlock_bh needs to be called before calling the validator. Since rcu_read_lock is not needed before the validator runs revert the hold and put added by3ad7d2468fand only do the hold when setting ifp->idev. 4. move duplicate address check and insertion of new address in the global address hash into a helper. The helper is called after an ifa is allocated and filled in. This allows the ifa for manually configured addresses to be done with GFP_KERNEL and reduces the overall amount of time with rcu_read_lock held and hash table spinlock held. Signed-off-by: David Ahern <dsahern@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David Ahern
David S. Miller
Родитель
6b1f8edaba
Коммит
f3d9832e56
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@ -957,18 +957,43 @@ static u32 inet6_addr_hash(const struct in6_addr *addr)
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return hash_32(ipv6_addr_hash(addr), IN6_ADDR_HSIZE_SHIFT);
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}
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static int ipv6_add_addr_hash(struct net_device *dev, struct inet6_ifaddr *ifa)
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{
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unsigned int hash;
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int err = 0;
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spin_lock(&addrconf_hash_lock);
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/* Ignore adding duplicate addresses on an interface */
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if (ipv6_chk_same_addr(dev_net(dev), &ifa->addr, dev)) {
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ADBG("ipv6_add_addr: already assigned\n");
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err = -EEXIST;
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goto out;
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}
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/* Add to big hash table */
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hash = inet6_addr_hash(&ifa->addr);
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hlist_add_head_rcu(&ifa->addr_lst, &inet6_addr_lst[hash]);
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out:
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spin_unlock(&addrconf_hash_lock);
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return err;
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}
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/* On success it returns ifp with increased reference count */
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static struct inet6_ifaddr *
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ipv6_add_addr(struct inet6_dev *idev, const struct in6_addr *addr,
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const struct in6_addr *peer_addr, int pfxlen,
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int scope, u32 flags, u32 valid_lft, u32 prefered_lft)
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int scope, u32 flags, u32 valid_lft, u32 prefered_lft,
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bool can_block)
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{
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gfp_t gfp_flags = can_block ? GFP_KERNEL : GFP_ATOMIC;
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struct net *net = dev_net(idev->dev);
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struct inet6_ifaddr *ifa = NULL;
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struct rt6_info *rt;
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struct rt6_info *rt = NULL;
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struct in6_validator_info i6vi;
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unsigned int hash;
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int err = 0;
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int addr_type = ipv6_addr_type(addr);
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@ -978,42 +1003,24 @@ ipv6_add_addr(struct inet6_dev *idev, const struct in6_addr *addr,
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addr_type & IPV6_ADDR_LOOPBACK))
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return ERR_PTR(-EADDRNOTAVAIL);
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rcu_read_lock_bh();
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in6_dev_hold(idev);
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if (idev->dead) {
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err = -ENODEV; /*XXX*/
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goto out2;
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goto out;
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}
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if (idev->cnf.disable_ipv6) {
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err = -EACCES;
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goto out2;
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goto out;
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}
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i6vi.i6vi_addr = *addr;
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i6vi.i6vi_dev = idev;
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rcu_read_unlock_bh();
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err = inet6addr_validator_notifier_call_chain(NETDEV_UP, &i6vi);
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rcu_read_lock_bh();
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err = notifier_to_errno(err);
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if (err)
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goto out2;
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spin_lock(&addrconf_hash_lock);
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/* Ignore adding duplicate addresses on an interface */
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if (ipv6_chk_same_addr(dev_net(idev->dev), addr, idev->dev)) {
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ADBG("ipv6_add_addr: already assigned\n");
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err = -EEXIST;
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if (err < 0)
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goto out;
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}
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ifa = kzalloc(sizeof(struct inet6_ifaddr), GFP_ATOMIC);
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ifa = kzalloc(sizeof(*ifa), gfp_flags);
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if (!ifa) {
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ADBG("ipv6_add_addr: malloc failed\n");
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err = -ENOBUFS;
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@ -1023,6 +1030,7 @@ ipv6_add_addr(struct inet6_dev *idev, const struct in6_addr *addr,
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rt = addrconf_dst_alloc(idev, addr, false);
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if (IS_ERR(rt)) {
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err = PTR_ERR(rt);
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rt = NULL;
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goto out;
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}
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@ -1053,16 +1061,21 @@ ipv6_add_addr(struct inet6_dev *idev, const struct in6_addr *addr,
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ifa->rt = rt;
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ifa->idev = idev;
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in6_dev_hold(idev);
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/* For caller */
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refcount_set(&ifa->refcnt, 1);
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/* Add to big hash table */
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hash = inet6_addr_hash(addr);
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rcu_read_lock_bh();
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hlist_add_head_rcu(&ifa->addr_lst, &inet6_addr_lst[hash]);
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spin_unlock(&addrconf_hash_lock);
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err = ipv6_add_addr_hash(idev->dev, ifa);
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if (err < 0) {
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rcu_read_unlock_bh();
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goto out;
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}
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write_lock(&idev->lock);
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/* Add to inet6_dev unicast addr list. */
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ipv6_link_dev_addr(idev, ifa);
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@ -1073,21 +1086,23 @@ ipv6_add_addr(struct inet6_dev *idev, const struct in6_addr *addr,
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in6_ifa_hold(ifa);
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write_unlock(&idev->lock);
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out2:
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rcu_read_unlock_bh();
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if (likely(err == 0))
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inet6addr_notifier_call_chain(NETDEV_UP, ifa);
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else {
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kfree(ifa);
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in6_dev_put(idev);
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inet6addr_notifier_call_chain(NETDEV_UP, ifa);
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out:
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if (unlikely(err < 0)) {
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if (rt)
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ip6_rt_put(rt);
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if (ifa) {
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if (ifa->idev)
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in6_dev_put(ifa->idev);
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kfree(ifa);
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}
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ifa = ERR_PTR(err);
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}
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return ifa;
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out:
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spin_unlock(&addrconf_hash_lock);
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goto out2;
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}
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enum cleanup_prefix_rt_t {
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@ -1334,7 +1349,7 @@ retry:
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ift = ipv6_add_addr(idev, &addr, NULL, tmp_plen,
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ipv6_addr_scope(&addr), addr_flags,
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tmp_valid_lft, tmp_prefered_lft);
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tmp_valid_lft, tmp_prefered_lft, true);
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if (IS_ERR(ift)) {
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in6_ifa_put(ifp);
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in6_dev_put(idev);
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@ -2018,7 +2033,7 @@ void addrconf_dad_failure(struct inet6_ifaddr *ifp)
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ifp2 = ipv6_add_addr(idev, &new_addr, NULL, pfxlen,
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scope, flags, valid_lft,
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preferred_lft);
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preferred_lft, false);
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if (IS_ERR(ifp2))
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goto lock_errdad;
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@ -2476,7 +2491,7 @@ int addrconf_prefix_rcv_add_addr(struct net *net, struct net_device *dev,
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pinfo->prefix_len,
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addr_type&IPV6_ADDR_SCOPE_MASK,
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addr_flags, valid_lft,
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prefered_lft);
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prefered_lft, false);
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if (IS_ERR_OR_NULL(ifp))
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return -1;
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@ -2845,7 +2860,7 @@ static int inet6_addr_add(struct net *net, int ifindex,
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}
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ifp = ipv6_add_addr(idev, pfx, peer_pfx, plen, scope, ifa_flags,
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valid_lft, prefered_lft);
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valid_lft, prefered_lft, true);
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if (!IS_ERR(ifp)) {
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if (!(ifa_flags & IFA_F_NOPREFIXROUTE)) {
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@ -2960,7 +2975,8 @@ static void add_addr(struct inet6_dev *idev, const struct in6_addr *addr,
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ifp = ipv6_add_addr(idev, addr, NULL, plen,
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scope, IFA_F_PERMANENT,
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INFINITY_LIFE_TIME, INFINITY_LIFE_TIME);
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INFINITY_LIFE_TIME, INFINITY_LIFE_TIME,
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true);
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if (!IS_ERR(ifp)) {
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spin_lock_bh(&ifp->lock);
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ifp->flags &= ~IFA_F_TENTATIVE;
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@ -3060,7 +3076,7 @@ void addrconf_add_linklocal(struct inet6_dev *idev,
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#endif
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ifp = ipv6_add_addr(idev, addr, NULL, 64, IFA_LINK, addr_flags,
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INFINITY_LIFE_TIME, INFINITY_LIFE_TIME);
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INFINITY_LIFE_TIME, INFINITY_LIFE_TIME, true);
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if (!IS_ERR(ifp)) {
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addrconf_prefix_route(&ifp->addr, ifp->prefix_len, idev->dev, 0, 0);
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addrconf_dad_start(ifp);
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