tcp: annotate sk->sk_wmem_queued lockless reads

[linux-2.6-block.git] / net / core / sock.c

diff --git a/net/core/sock.c b/net/core/sock.c
index 07863edbe6fc4842e47ebebf00bc21bc406d9264..a515392ba84b67b2bf5400e0cfb7c3454fa87af8 100644 (file)
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -522,7 +522,7 @@ int __sk_receive_skb(struct sock *sk, struct sk_buff *skb,
                rc = sk_backlog_rcv(sk, skb);
 
                mutex_release(&sk->sk_lock.dep_map, 1, _RET_IP_);
-       } else if (sk_add_backlog(sk, skb, sk->sk_rcvbuf)) {
+       } else if (sk_add_backlog(sk, skb, READ_ONCE(sk->sk_rcvbuf))) {
                bh_unlock_sock(sk);
                atomic_inc(&sk->sk_drops);
                goto discard_and_relse;
@@ -785,7 +785,8 @@ set_sndbuf:
                 */
                val = min_t(int, val, INT_MAX / 2);
                sk->sk_userlocks |= SOCK_SNDBUF_LOCK;
-               sk->sk_sndbuf = max_t(int, val * 2, SOCK_MIN_SNDBUF);
+               WRITE_ONCE(sk->sk_sndbuf,
+                          max_t(int, val * 2, SOCK_MIN_SNDBUF));
                /* Wake up sending tasks if we upped the value. */
                sk->sk_write_space(sk);
                break;
@@ -831,7 +832,8 @@ set_rcvbuf:
                 * returning the value we actually used in getsockopt
                 * is the most desirable behavior.
                 */
-               sk->sk_rcvbuf = max_t(int, val * 2, SOCK_MIN_RCVBUF);
+               WRITE_ONCE(sk->sk_rcvbuf,
+                          max_t(int, val * 2, SOCK_MIN_RCVBUF));
                break;
 
        case SO_RCVBUFFORCE:
@@ -974,7 +976,7 @@ set_rcvbuf:
                if (sock->ops->set_rcvlowat)
                        ret = sock->ops->set_rcvlowat(sk, val);
                else
-                       sk->sk_rcvlowat = val ? : 1;
+                       WRITE_ONCE(sk->sk_rcvlowat, val ? : 1);
                break;
 
        case SO_RCVTIMEO_OLD:
@@ -1700,8 +1702,6 @@ static void __sk_destruct(struct rcu_head *head)
                sk_filter_uncharge(sk, filter);
                RCU_INIT_POINTER(sk->sk_filter, NULL);
        }
-       if (rcu_access_pointer(sk->sk_reuseport_cb))
-               reuseport_detach_sock(sk);
 
        sock_disable_timestamp(sk, SK_FLAGS_TIMESTAMP);
 
@@ -1728,7 +1728,14 @@ static void __sk_destruct(struct rcu_head *head)
 
 void sk_destruct(struct sock *sk)
 {
-       if (sock_flag(sk, SOCK_RCU_FREE))
+       bool use_call_rcu = sock_flag(sk, SOCK_RCU_FREE);
+
+       if (rcu_access_pointer(sk->sk_reuseport_cb)) {
+               reuseport_detach_sock(sk);
+               use_call_rcu = true;
+       }
+
+       if (use_call_rcu)
                call_rcu(&sk->sk_rcu, __sk_destruct);
        else
                __sk_destruct(&sk->sk_rcu);
@@ -2083,8 +2090,10 @@ EXPORT_SYMBOL(sock_i_ino);
 struct sk_buff *sock_wmalloc(struct sock *sk, unsigned long size, int force,
                             gfp_t priority)
 {
-       if (force || refcount_read(&sk->sk_wmem_alloc) < sk->sk_sndbuf) {
+       if (force ||
+           refcount_read(&sk->sk_wmem_alloc) < READ_ONCE(sk->sk_sndbuf)) {
                struct sk_buff *skb = alloc_skb(size, priority);
+
                if (skb) {
                        skb_set_owner_w(skb, sk);
                        return skb;
@@ -2185,7 +2194,7 @@ static long sock_wait_for_wmem(struct sock *sk, long timeo)
                        break;
                set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
                prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
-               if (refcount_read(&sk->sk_wmem_alloc) < sk->sk_sndbuf)
+               if (refcount_read(&sk->sk_wmem_alloc) < READ_ONCE(sk->sk_sndbuf))
                        break;
                if (sk->sk_shutdown & SEND_SHUTDOWN)
                        break;
@@ -2220,7 +2229,7 @@ struct sk_buff *sock_alloc_send_pskb(struct sock *sk, unsigned long header_len,
                if (sk->sk_shutdown & SEND_SHUTDOWN)
                        goto failure;
 
-               if (sk_wmem_alloc_get(sk) < sk->sk_sndbuf)
+               if (sk_wmem_alloc_get(sk) < READ_ONCE(sk->sk_sndbuf))
                        break;
 
                sk_set_bit(SOCKWQ_ASYNC_NOSPACE, sk);
@@ -2329,8 +2338,8 @@ static void sk_leave_memory_pressure(struct sock *sk)
        } else {
                unsigned long *memory_pressure = sk->sk_prot->memory_pressure;
 
-               if (memory_pressure && *memory_pressure)
-                       *memory_pressure = 0;
+               if (memory_pressure && READ_ONCE(*memory_pressure))
+                       WRITE_ONCE(*memory_pressure, 0);
        }
 }
 
@@ -2801,7 +2810,7 @@ static void sock_def_write_space(struct sock *sk)
        /* Do not wake up a writer until he can make "significant"
         * progress.  --DaveM
         */
-       if ((refcount_read(&sk->sk_wmem_alloc) << 1) <= sk->sk_sndbuf) {
+       if ((refcount_read(&sk->sk_wmem_alloc) << 1) <= READ_ONCE(sk->sk_sndbuf)) {
                wq = rcu_dereference(sk->sk_wq);
                if (skwq_has_sleeper(wq))
                        wake_up_interruptible_sync_poll(&wq->wait, EPOLLOUT |
@@ -3199,13 +3208,13 @@ void sk_get_meminfo(const struct sock *sk, u32 *mem)
        memset(mem, 0, sizeof(*mem) * SK_MEMINFO_VARS);
 
        mem[SK_MEMINFO_RMEM_ALLOC] = sk_rmem_alloc_get(sk);
-       mem[SK_MEMINFO_RCVBUF] = sk->sk_rcvbuf;
+       mem[SK_MEMINFO_RCVBUF] = READ_ONCE(sk->sk_rcvbuf);
        mem[SK_MEMINFO_WMEM_ALLOC] = sk_wmem_alloc_get(sk);
-       mem[SK_MEMINFO_SNDBUF] = sk->sk_sndbuf;
+       mem[SK_MEMINFO_SNDBUF] = READ_ONCE(sk->sk_sndbuf);
        mem[SK_MEMINFO_FWD_ALLOC] = sk->sk_forward_alloc;
-       mem[SK_MEMINFO_WMEM_QUEUED] = sk->sk_wmem_queued;
+       mem[SK_MEMINFO_WMEM_QUEUED] = READ_ONCE(sk->sk_wmem_queued);
        mem[SK_MEMINFO_OPTMEM] = atomic_read(&sk->sk_omem_alloc);
-       mem[SK_MEMINFO_BACKLOG] = sk->sk_backlog.len;
+       mem[SK_MEMINFO_BACKLOG] = READ_ONCE(sk->sk_backlog.len);
        mem[SK_MEMINFO_DROPS] = atomic_read(&sk->sk_drops);
 }
 
@@ -3492,7 +3501,7 @@ static long sock_prot_memory_allocated(struct proto *proto)
        return proto->memory_allocated != NULL ? proto_memory_allocated(proto) : -1L;
 }
 
-static char *sock_prot_memory_pressure(struct proto *proto)
+static const char *sock_prot_memory_pressure(struct proto *proto)
 {
        return proto->memory_pressure != NULL ?
        proto_memory_pressure(proto) ? "yes" : "no" : "NI";