[SCTP]: Handle address add/delete events in a more efficient way.

Currently in SCTP, we maintain a local address list by rebuilding the whole
list from the device list whenever we get a address add/delete event.

This patch fixes it by only adding/deleting the address for which we
receive the event.

Also removed the sctp_local_addr_lock() which is no longer needed as we
now use list_for_each_safe() to traverse this list. This fixes the bugs
in sctp_copy_laddrs_xxx() routines where we do copy_to_user() while
holding this lock.

Signed-off-by: Sridhar Samudrala <sri@us.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 10 insertions, 24 deletions

diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index 1e8132b8c4d9..fa29eae83e91 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -3821,10 +3821,9 @@ static int sctp_getsockopt_local_addrs_num_old(struct sock *sk, int len,
         sctp_assoc_t id;
         struct sctp_bind_addr *bp;
         struct sctp_association *asoc;
-        struct list_head *pos;
+        struct list_head *pos, *temp;
         struct sctp_sockaddr_entry *addr;
         rwlock_t *addr_lock;
-        unsigned long flags;
         int cnt = 0;
 
         if (len != sizeof(sctp_assoc_t))
@@ -3859,8 +3858,7 @@ static int sctp_getsockopt_local_addrs_num_old(struct sock *sk, int len,
                 addr = list_entry(bp->address_list.next,
                                   struct sctp_sockaddr_entry, list);
                 if (sctp_is_any(&addr->a)) {
-                        sctp_spin_lock_irqsave(&sctp_local_addr_lock, flags);
-                        list_for_each(pos, &sctp_local_addr_list) {
+                        list_for_each_safe(pos, temp, &sctp_local_addr_list) {
                                 addr = list_entry(pos,
                                                   struct sctp_sockaddr_entry,
                                                   list);
@@ -3869,8 +3867,6 @@ static int sctp_getsockopt_local_addrs_num_old(struct sock *sk, int len,
                                         continue;
                                 cnt++;
                         }
-                        sctp_spin_unlock_irqrestore(&sctp_local_addr_lock,
-                                                    flags);
                 } else {
                         cnt = 1;
                 }
@@ -3892,15 +3888,13 @@ done:
 static int sctp_copy_laddrs_to_user_old(struct sock *sk, __u16 port, int max_addrs,
                                         void __user *to)
 {
-        struct list_head *pos;
+        struct list_head *pos, *next;
         struct sctp_sockaddr_entry *addr;
-        unsigned long flags;
         union sctp_addr temp;
         int cnt = 0;
         int addrlen;
 
-        sctp_spin_lock_irqsave(&sctp_local_addr_lock, flags);
-        list_for_each(pos, &sctp_local_addr_list) {
+        list_for_each_safe(pos, next, &sctp_local_addr_list) {
                 addr = list_entry(pos, struct sctp_sockaddr_entry, list);
                 if ((PF_INET == sk->sk_family) && 
                     (AF_INET6 == addr->a.sa.sa_family))
@@ -3909,16 +3903,13 @@ static int sctp_copy_laddrs_to_user_old(struct sock *sk, __u16 port, int max_add
                 sctp_get_pf_specific(sk->sk_family)->addr_v4map(sctp_sk(sk),
                                                                 &temp);
                 addrlen = sctp_get_af_specific(temp.sa.sa_family)->sockaddr_len;
-                if (copy_to_user(to, &temp, addrlen)) {
-                        sctp_spin_unlock_irqrestore(&sctp_local_addr_lock,
-                                                    flags);
+                if (copy_to_user(to, &temp, addrlen))
                         return -EFAULT;
-                }
+
                 to += addrlen;
                 cnt ++;
                 if (cnt >= max_addrs) break;
         }
-        sctp_spin_unlock_irqrestore(&sctp_local_addr_lock, flags);
 
         return cnt;
 }
@@ -3926,15 +3917,13 @@ static int sctp_copy_laddrs_to_user_old(struct sock *sk, __u16 port, int max_add
 static int sctp_copy_laddrs_to_user(struct sock *sk, __u16 port,
                                     void __user **to, size_t space_left)
 {
-        struct list_head *pos;
+        struct list_head *pos, *next;
         struct sctp_sockaddr_entry *addr;
-        unsigned long flags;
         union sctp_addr temp;
         int cnt = 0;
         int addrlen;
 
-        sctp_spin_lock_irqsave(&sctp_local_addr_lock, flags);
-        list_for_each(pos, &sctp_local_addr_list) {
+        list_for_each_safe(pos, next, &sctp_local_addr_list) {
                 addr = list_entry(pos, struct sctp_sockaddr_entry, list);
                 if ((PF_INET == sk->sk_family) && 
                     (AF_INET6 == addr->a.sa.sa_family))
@@ -3945,16 +3934,13 @@ static int sctp_copy_laddrs_to_user(struct sock *sk, __u16 port,
                 addrlen = sctp_get_af_specific(temp.sa.sa_family)->sockaddr_len;
                 if(space_left<addrlen)
                         return -ENOMEM;
-                if (copy_to_user(*to, &temp, addrlen)) {
-                        sctp_spin_unlock_irqrestore(&sctp_local_addr_lock,
-                                                    flags);
+                if (copy_to_user(*to, &temp, addrlen))
                         return -EFAULT;
-                }
+
                 *to += addrlen;
                 cnt ++;
                 space_left -= addrlen;
         }
-        sctp_spin_unlock_irqrestore(&sctp_local_addr_lock, flags);
 
         return cnt;
 }