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authorEric Dumazet <edumazet@google.com>2019-10-10 20:17:46 -0700
committerDavid S. Miller <davem@davemloft.net>2019-10-13 10:13:08 -0700
commitab4e846a82d0ae00176de19f2db3c5c64f8eb5f2 (patch)
tree7be26ef02ab2f2979be9a3cdeb36ed1bafc51354 /include/net/sock.h
parenttcp: annotate sk->sk_sndbuf lockless reads (diff)
downloadlinux-dev-ab4e846a82d0ae00176de19f2db3c5c64f8eb5f2.tar.xz
linux-dev-ab4e846a82d0ae00176de19f2db3c5c64f8eb5f2.zip
tcp: annotate sk->sk_wmem_queued lockless reads
For the sake of tcp_poll(), there are few places where we fetch sk->sk_wmem_queued while this field can change from IRQ or other cpu. We need to add READ_ONCE() annotations, and also make sure write sides use corresponding WRITE_ONCE() to avoid store-tearing. sk_wmem_queued_add() helper is added so that we can in the future convert to ADD_ONCE() or equivalent if/when available. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/net/sock.h')
-rw-r--r--include/net/sock.h15
1 files changed, 10 insertions, 5 deletions
diff --git a/include/net/sock.h b/include/net/sock.h
index 3d1e7502333e..f69b58bff7e5 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -878,12 +878,17 @@ static inline bool sk_acceptq_is_full(const struct sock *sk)
*/
static inline int sk_stream_min_wspace(const struct sock *sk)
{
- return sk->sk_wmem_queued >> 1;
+ return READ_ONCE(sk->sk_wmem_queued) >> 1;
}
static inline int sk_stream_wspace(const struct sock *sk)
{
- return READ_ONCE(sk->sk_sndbuf) - sk->sk_wmem_queued;
+ return READ_ONCE(sk->sk_sndbuf) - READ_ONCE(sk->sk_wmem_queued);
+}
+
+static inline void sk_wmem_queued_add(struct sock *sk, int val)
+{
+ WRITE_ONCE(sk->sk_wmem_queued, sk->sk_wmem_queued + val);
}
void sk_stream_write_space(struct sock *sk);
@@ -1207,7 +1212,7 @@ static inline void sk_refcnt_debug_release(const struct sock *sk)
static inline bool __sk_stream_memory_free(const struct sock *sk, int wake)
{
- if (sk->sk_wmem_queued >= READ_ONCE(sk->sk_sndbuf))
+ if (READ_ONCE(sk->sk_wmem_queued) >= READ_ONCE(sk->sk_sndbuf))
return false;
return sk->sk_prot->stream_memory_free ?
@@ -1467,7 +1472,7 @@ DECLARE_STATIC_KEY_FALSE(tcp_tx_skb_cache_key);
static inline void sk_wmem_free_skb(struct sock *sk, struct sk_buff *skb)
{
sock_set_flag(sk, SOCK_QUEUE_SHRUNK);
- sk->sk_wmem_queued -= skb->truesize;
+ sk_wmem_queued_add(sk, -skb->truesize);
sk_mem_uncharge(sk, skb->truesize);
if (static_branch_unlikely(&tcp_tx_skb_cache_key) &&
!sk->sk_tx_skb_cache && !skb_cloned(skb)) {
@@ -2014,7 +2019,7 @@ static inline int skb_copy_to_page_nocache(struct sock *sk, struct iov_iter *fro
skb->len += copy;
skb->data_len += copy;
skb->truesize += copy;
- sk->sk_wmem_queued += copy;
+ sk_wmem_queued_add(sk, copy);
sk_mem_charge(sk, copy);
return 0;
}