diff options
| author | Eric Dumazet <edumazet@google.com> | 2019-10-11 06:17:46 +0300 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2019-10-13 20:13:08 +0300 |
| commit | ab4e846a82d0ae00176de19f2db3c5c64f8eb5f2 (patch) | |
| tree | 7be26ef02ab2f2979be9a3cdeb36ed1bafc51354 /include | |
| parent | e292f05e0df73f9fcc93329663936e1ded97a988 (diff) | |
| download | linux-ab4e846a82d0ae00176de19f2db3c5c64f8eb5f2.tar.xz | |
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')
| -rw-r--r-- | include/net/sock.h | 15 | ||||
| -rw-r--r-- | include/trace/events/sock.h | 2 |
2 files changed, 11 insertions, 6 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; } diff --git a/include/trace/events/sock.h b/include/trace/events/sock.h index f720c32e7dfd..51fe9f6719eb 100644 --- a/include/trace/events/sock.h +++ b/include/trace/events/sock.h @@ -115,7 +115,7 @@ TRACE_EVENT(sock_exceed_buf_limit, __entry->rmem_alloc = atomic_read(&sk->sk_rmem_alloc); __entry->sysctl_wmem = sk_get_wmem0(sk, prot); __entry->wmem_alloc = refcount_read(&sk->sk_wmem_alloc); - __entry->wmem_queued = sk->sk_wmem_queued; + __entry->wmem_queued = READ_ONCE(sk->sk_wmem_queued); __entry->kind = kind; ), |