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authorEric Dumazet <edumazet@google.com>2019-10-10 20:17:45 -0700
committerDavid S. Miller <davem@davemloft.net>2019-10-13 10:13:08 -0700
commite292f05e0df73f9fcc93329663936e1ded97a988 (patch)
tree441d2a07b24a8dc89e22f14b373ccbcdf6377b34 /include
parenttcp: annotate sk->sk_rcvbuf lockless reads (diff)
downloadlinux-dev-e292f05e0df73f9fcc93329663936e1ded97a988.tar.xz
linux-dev-e292f05e0df73f9fcc93329663936e1ded97a988.zip
tcp: annotate sk->sk_sndbuf lockless reads
For the sake of tcp_poll(), there are few places where we fetch sk->sk_sndbuf 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. Note that other transports probably need similar fixes. 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.h18
1 files changed, 11 insertions, 7 deletions
diff --git a/include/net/sock.h b/include/net/sock.h
index 79f54e1f8827..3d1e7502333e 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -883,7 +883,7 @@ static inline int sk_stream_min_wspace(const struct sock *sk)
static inline int sk_stream_wspace(const struct sock *sk)
{
- return sk->sk_sndbuf - sk->sk_wmem_queued;
+ return READ_ONCE(sk->sk_sndbuf) - sk->sk_wmem_queued;
}
void sk_stream_write_space(struct sock *sk);
@@ -1207,7 +1207,7 @@ 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 >= sk->sk_sndbuf)
+ if (sk->sk_wmem_queued >= READ_ONCE(sk->sk_sndbuf))
return false;
return sk->sk_prot->stream_memory_free ?
@@ -2220,10 +2220,14 @@ static inline void sk_wake_async(const struct sock *sk, int how, int band)
static inline void sk_stream_moderate_sndbuf(struct sock *sk)
{
- if (!(sk->sk_userlocks & SOCK_SNDBUF_LOCK)) {
- sk->sk_sndbuf = min(sk->sk_sndbuf, sk->sk_wmem_queued >> 1);
- sk->sk_sndbuf = max_t(u32, sk->sk_sndbuf, SOCK_MIN_SNDBUF);
- }
+ u32 val;
+
+ if (sk->sk_userlocks & SOCK_SNDBUF_LOCK)
+ return;
+
+ val = min(sk->sk_sndbuf, sk->sk_wmem_queued >> 1);
+
+ WRITE_ONCE(sk->sk_sndbuf, max_t(u32, val, SOCK_MIN_SNDBUF));
}
struct sk_buff *sk_stream_alloc_skb(struct sock *sk, int size, gfp_t gfp,
@@ -2251,7 +2255,7 @@ bool sk_page_frag_refill(struct sock *sk, struct page_frag *pfrag);
*/
static inline bool sock_writeable(const struct sock *sk)
{
- return refcount_read(&sk->sk_wmem_alloc) < (sk->sk_sndbuf >> 1);
+ return refcount_read(&sk->sk_wmem_alloc) < (READ_ONCE(sk->sk_sndbuf) >> 1);
}
static inline gfp_t gfp_any(void)