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Commit fc766e4c authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
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decnet: RCU conversion and get rid of dev_base_lock 

While tracking dev_base_lock users, I found decnet used it in
dnet_select_source(), but for a wrong purpose:

Writers only hold RTNL, not dev_base_lock, so readers must use RCU if
they cannot use RTNL.

Adds an rcu_head in struct dn_ifaddr and handle proper RCU management.

Adds __rcu annotation in dn_route as well.
Signed-off-by: default avatarEric Dumazet <eric.dumazet@gmail.com>
Acked-by: default avatarSteven Whitehouse <swhiteho@redhat.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent e4a7b93b
Expand all Hide whitespace changes
Inline Side-by-side
Showing with 127 additions and 88 deletions
include/linux/netdevice.h
View file @ fc766e4c
......@@ -951,7 +951,7 @@ struct net_device {
#endif
void *atalk_ptr; /* AppleTalk link */
struct in_device __rcu *ip_ptr; /* IPv4 specific data */
void *dn_ptr; /* DECnet specific data */
struct dn_dev __rcu *dn_ptr; /* DECnet specific data */
struct inet6_dev __rcu *ip6_ptr; /* IPv6 specific data */
void *ec_ptr; /* Econet specific data */
void *ax25_ptr; /* AX.25 specific data */
......
include/net/dn_dev.h
View file @ fc766e4c
......@@ -5,13 +5,14 @@
struct dn_dev;
struct dn_ifaddr {
struct dn_ifaddr *ifa_next;
struct dn_ifaddr __rcu *ifa_next;
struct dn_dev *ifa_dev;
__le16 ifa_local;
__le16 ifa_address;
__u8 ifa_flags;
__u8 ifa_scope;
char ifa_label[IFNAMSIZ];
struct rcu_head rcu;
};
#define DN_DEV_S_RU 0 /* Run - working normally */
......@@ -83,7 +84,7 @@ struct dn_dev_parms {
struct dn_dev {
struct dn_ifaddr *ifa_list;
struct dn_ifaddr __rcu *ifa_list;
struct net_device *dev;
struct dn_dev_parms parms;
char use_long;
......@@ -171,19 +172,27 @@ extern int unregister_dnaddr_notifier(struct notifier_block *nb);
static inline int dn_dev_islocal(struct net_device *dev, __le16 addr)
{
struct dn_dev *dn_db = dev->dn_ptr;
struct dn_dev *dn_db;
struct dn_ifaddr *ifa;
int res = 0;
rcu_read_lock();
dn_db = rcu_dereference(dev->dn_ptr);
if (dn_db == NULL) {
printk(KERN_DEBUG "dn_dev_islocal: Called for non DECnet device\n");
return 0;
goto out;
}
for(ifa = dn_db->ifa_list; ifa; ifa = ifa->ifa_next)
if ((addr ^ ifa->ifa_local) == 0)
return 1;
return 0;
for (ifa = rcu_dereference(dn_db->ifa_list);
ifa != NULL;
ifa = rcu_dereference(ifa->ifa_next))
if ((addr ^ ifa->ifa_local) == 0) {
res = 1;
break;
}
out:
rcu_read_unlock();
return res;
}
#endif /* _NET_DN_DEV_H */
include/net/dst.h
View file @ fc766e4c
......@@ -94,10 +94,10 @@ struct dst_entry {
int __use;
unsigned long lastuse;
union {
struct dst_entry *next;
struct rtable __rcu *rt_next;
struct rt6_info *rt6_next;
struct dn_route *dn_next;
struct dst_entry *next;
struct rtable __rcu *rt_next;
struct rt6_info *rt6_next;
struct dn_route __rcu *dn_next;
};
};
......
net/decnet/af_decnet.c
View file @ fc766e4c
......@@ -1848,7 +1848,7 @@ unsigned dn_mss_from_pmtu(struct net_device *dev, int mtu)
{
unsigned mss = 230 - DN_MAX_NSP_DATA_HEADER;
if (dev) {
struct dn_dev *dn_db = dev->dn_ptr;
struct dn_dev *dn_db = rcu_dereference_raw(dev->dn_ptr);
mtu -= LL_RESERVED_SPACE(dev);
if (dn_db->use_long)
mtu -= 21;
......
net/decnet/dn_dev.c
View file @ fc766e4c
This diff is collapsed.
net/decnet/dn_fib.c
View file @ fc766e4c
......@@ -610,10 +610,12 @@ static void dn_fib_del_ifaddr(struct dn_ifaddr *ifa)
/* Scan device list */
rcu_read_lock();
for_each_netdev_rcu(&init_net, dev) {
dn_db = dev->dn_ptr;
dn_db = rcu_dereference(dev->dn_ptr);
if (dn_db == NULL)
continue;
for(ifa2 = dn_db->ifa_list; ifa2; ifa2 = ifa2->ifa_next) {
for (ifa2 = rcu_dereference(dn_db->ifa_list);
ifa2 != NULL;
ifa2 = rcu_dereference(ifa2->ifa_next)) {
if (ifa2->ifa_local == ifa->ifa_local) {
found_it = 1;
break;
......
net/decnet/dn_neigh.c
View file @ fc766e4c
......@@ -391,7 +391,7 @@ int dn_neigh_router_hello(struct sk_buff *skb)
write_lock(&neigh->lock);
neigh->used = jiffies;
dn_db = (struct dn_dev *)neigh->dev->dn_ptr;
dn_db = rcu_dereference(neigh->dev->dn_ptr);
if (!(neigh->nud_state & NUD_PERMANENT)) {
neigh->updated = jiffies;
......
net/decnet/dn_route.c
View file @ fc766e4c
......@@ -93,7 +93,7 @@
struct dn_rt_hash_bucket
{
struct dn_route *chain;
struct dn_route __rcu *chain;
spinlock_t lock;
};
......@@ -157,15 +157,17 @@ static inline void dnrt_drop(struct dn_route *rt)
static void dn_dst_check_expire(unsigned long dummy)
{
int i;
struct dn_route *rt, **rtp;
struct dn_route *rt;
struct dn_route __rcu **rtp;
unsigned long now = jiffies;
unsigned long expire = 120 * HZ;
for(i = 0; i <= dn_rt_hash_mask; i++) {
for (i = 0; i <= dn_rt_hash_mask; i++) {
rtp = &dn_rt_hash_table[i].chain;
spin_lock(&dn_rt_hash_table[i].lock);
while((rt=*rtp) != NULL) {
while ((rt = rcu_dereference_protected(*rtp,
lockdep_is_held(&dn_rt_hash_table[i].lock))) != NULL) {
if (atomic_read(&rt->dst.__refcnt) ||
(now - rt->dst.lastuse) < expire) {
rtp = &rt->dst.dn_next;
......@@ -186,17 +188,19 @@ static void dn_dst_check_expire(unsigned long dummy)
static int dn_dst_gc(struct dst_ops *ops)
{
struct dn_route *rt, **rtp;
struct dn_route *rt;
struct dn_route __rcu **rtp;
int i;
unsigned long now = jiffies;
unsigned long expire = 10 * HZ;
for(i = 0; i <= dn_rt_hash_mask; i++) {
for (i = 0; i <= dn_rt_hash_mask; i++) {
spin_lock_bh(&dn_rt_hash_table[i].lock);
rtp = &dn_rt_hash_table[i].chain;
while((rt=*rtp) != NULL) {
while ((rt = rcu_dereference_protected(*rtp,
lockdep_is_held(&dn_rt_hash_table[i].lock))) != NULL) {
if (atomic_read(&rt->dst.__refcnt) ||
(now - rt->dst.lastuse) < expire) {
rtp = &rt->dst.dn_next;
......@@ -227,7 +231,7 @@ static void dn_dst_update_pmtu(struct dst_entry *dst, u32 mtu)
{
u32 min_mtu = 230;
struct dn_dev *dn = dst->neighbour ?
(struct dn_dev *)dst->neighbour->dev->dn_ptr : NULL;
rcu_dereference_raw(dst->neighbour->dev->dn_ptr) : NULL;
if (dn && dn->use_long == 0)
min_mtu -= 6;
......@@ -277,13 +281,15 @@ static inline int compare_keys(struct flowi *fl1, struct flowi *fl2)
static int dn_insert_route(struct dn_route *rt, unsigned hash, struct dn_route **rp)
{
struct dn_route *rth, **rthp;
struct dn_route *rth;
struct dn_route __rcu **rthp;
unsigned long now = jiffies;
rthp = &dn_rt_hash_table[hash].chain;
spin_lock_bh(&dn_rt_hash_table[hash].lock);
while((rth = *rthp) != NULL) {
while ((rth = rcu_dereference_protected(*rthp,
lockdep_is_held(&dn_rt_hash_table[hash].lock))) != NULL) {
if (compare_keys(&rth->fl, &rt->fl)) {
/* Put it first */
*rthp = rth->dst.dn_next;
......@@ -315,15 +321,15 @@ static void dn_run_flush(unsigned long dummy)
int i;
struct dn_route *rt, *next;
for(i = 0; i < dn_rt_hash_mask; i++) {
for (i = 0; i < dn_rt_hash_mask; i++) {
spin_lock_bh(&dn_rt_hash_table[i].lock);
if ((rt = xchg(&dn_rt_hash_table[i].chain, NULL)) == NULL)
if ((rt = xchg((struct dn_route **)&dn_rt_hash_table[i].chain, NULL)) == NULL)
goto nothing_to_declare;
for(; rt; rt=next) {
next = rt->dst.dn_next;
rt->dst.dn_next = NULL;
for(; rt; rt = next) {
next = rcu_dereference_raw(rt->dst.dn_next);
RCU_INIT_POINTER(rt->dst.dn_next, NULL);
dst_free((struct dst_entry *)rt);
}
......@@ -458,15 +464,16 @@ static int dn_return_long(struct sk_buff *skb)
*/
static int dn_route_rx_packet(struct sk_buff *skb)
{
struct dn_skb_cb *cb = DN_SKB_CB(skb);
struct dn_skb_cb *cb;
int err;
if ((err = dn_route_input(skb)) == 0)
return dst_input(skb);
cb = DN_SKB_CB(skb);
if (decnet_debug_level & 4) {
char *devname = skb->dev ? skb->dev->name : "???";
struct dn_skb_cb *cb = DN_SKB_CB(skb);
printk(KERN_DEBUG
"DECnet: dn_route_rx_packet: rt_flags=0x%02x dev=%s len=%d src=0x%04hx dst=0x%04hx err=%d type=%d\n",
(int)cb->rt_flags, devname, skb->len,
......@@ -573,7 +580,7 @@ int dn_route_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type
struct dn_skb_cb *cb;
unsigned char flags = 0;
__u16 len = le16_to_cpu(*(__le16 *)skb->data);
struct dn_dev *dn = (struct dn_dev *)dev->dn_ptr;
struct dn_dev *dn = rcu_dereference(dev->dn_ptr);
unsigned char padlen = 0;
if (!net_eq(dev_net(dev), &init_net))
......@@ -728,7 +735,7 @@ static int dn_forward(struct sk_buff *skb)
{
struct dn_skb_cb *cb = DN_SKB_CB(skb);
struct dst_entry *dst = skb_dst(skb);
struct dn_dev *dn_db = dst->dev->dn_ptr;
struct dn_dev *dn_db = rcu_dereference(dst->dev->dn_ptr);
struct dn_route *rt;
struct neighbour *neigh = dst->neighbour;
int header_len;
......@@ -835,13 +842,16 @@ static inline int dn_match_addr(__le16 addr1, __le16 addr2)
static __le16 dnet_select_source(const struct net_device *dev, __le16 daddr, int scope)
{
__le16 saddr = 0;
struct dn_dev *dn_db = dev->dn_ptr;
struct dn_dev *dn_db;
struct dn_ifaddr *ifa;
int best_match = 0;
int ret;
read_lock(&dev_base_lock);
for(ifa = dn_db->ifa_list; ifa; ifa = ifa->ifa_next) {
rcu_read_lock();
dn_db = rcu_dereference(dev->dn_ptr);
for (ifa = rcu_dereference(dn_db->ifa_list);
ifa != NULL;
ifa = rcu_dereference(ifa->ifa_next)) {
if (ifa->ifa_scope > scope)
continue;
if (!daddr) {
......@@ -854,7 +864,7 @@ static __le16 dnet_select_source(const struct net_device *dev, __le16 daddr, int
if (best_match == 0)
saddr = ifa->ifa_local;
}
read_unlock(&dev_base_lock);
rcu_read_unlock();
return saddr;
}
......@@ -1020,7 +1030,7 @@ static int dn_route_output_slow(struct dst_entry **pprt, const struct flowi *old
err = -ENODEV;
if (dev_out == NULL)
goto out;
dn_db = dev_out->dn_ptr;
dn_db = rcu_dereference_raw(dev_out->dn_ptr);
/* Possible improvement - check all devices for local addr */
if (dn_dev_islocal(dev_out, fl.fld_dst)) {
dev_put(dev_out);
......@@ -1233,7 +1243,7 @@ static int dn_route_input_slow(struct sk_buff *skb)
dev_hold(in_dev);
if ((dn_db = in_dev->dn_ptr) == NULL)
if ((dn_db = rcu_dereference(in_dev->dn_ptr)) == NULL)
goto out;
/* Zero source addresses are not allowed */
......@@ -1677,15 +1687,15 @@ static struct dn_route *dn_rt_cache_get_next(struct seq_file *seq, struct dn_rou
{
struct dn_rt_cache_iter_state *s = seq->private;
rt = rt->dst.dn_next;
while(!rt) {
rt = rcu_dereference_bh(rt->dst.dn_next);
while (!rt) {
rcu_read_unlock_bh();
if (--s->bucket < 0)
break;
rcu_read_lock_bh();
rt = dn_rt_hash_table[s->bucket].chain;
rt = rcu_dereference_bh(dn_rt_hash_table[s->bucket].chain);
}
return rcu_dereference_bh(rt);
return rt;
}
static void *dn_rt_cache_seq_start(struct seq_file *seq, loff_t *pos)
......
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