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authorEric Dumazet <edumazet@google.com>2015-09-25 17:39:22 +0300
committerDavid S. Miller <davem@davemloft.net>2015-09-25 23:00:39 +0300
commit802885fc0400d0166a6b65d1844b61696aecbb10 (patch)
tree7f6e6d083adf632704d496642eab95ad3c969e93
parent0f935dbedc49a5044ebff08b47eef35a2f2bbe92 (diff)
downloadlinux-802885fc0400d0166a6b65d1844b61696aecbb10.tar.xz
dccp: constify dccp_make_response() socket argument
Like tcp_make_synack() the only time we might change the socket is when calling sock_wmalloc(), which is using atomic operation to update sk->sk_wmem_alloc Also use MAX_DCCP_HEADER as both IPv4/IPv6 use this value for max_header. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--net/dccp/dccp.h2
-rw-r--r--net/dccp/output.c17
2 files changed, 12 insertions, 7 deletions
diff --git a/net/dccp/dccp.h b/net/dccp/dccp.h
index bebc735f5afc..31e96df500d1 100644
--- a/net/dccp/dccp.h
+++ b/net/dccp/dccp.h
@@ -293,7 +293,7 @@ int dccp_init_sock(struct sock *sk, const __u8 ctl_sock_initialized);
void dccp_destroy_sock(struct sock *sk);
void dccp_close(struct sock *sk, long timeout);
-struct sk_buff *dccp_make_response(struct sock *sk, struct dst_entry *dst,
+struct sk_buff *dccp_make_response(const struct sock *sk, struct dst_entry *dst,
struct request_sock *req);
int dccp_connect(struct sock *sk);
diff --git a/net/dccp/output.c b/net/dccp/output.c
index 0248e8a3460c..4ce912e691d0 100644
--- a/net/dccp/output.c
+++ b/net/dccp/output.c
@@ -390,7 +390,7 @@ int dccp_retransmit_skb(struct sock *sk)
return dccp_transmit_skb(sk, skb_clone(sk->sk_send_head, GFP_ATOMIC));
}
-struct sk_buff *dccp_make_response(struct sock *sk, struct dst_entry *dst,
+struct sk_buff *dccp_make_response(const struct sock *sk, struct dst_entry *dst,
struct request_sock *req)
{
struct dccp_hdr *dh;
@@ -398,13 +398,18 @@ struct sk_buff *dccp_make_response(struct sock *sk, struct dst_entry *dst,
const u32 dccp_header_size = sizeof(struct dccp_hdr) +
sizeof(struct dccp_hdr_ext) +
sizeof(struct dccp_hdr_response);
- struct sk_buff *skb = sock_wmalloc(sk, sk->sk_prot->max_header, 1,
- GFP_ATOMIC);
- if (skb == NULL)
+ struct sk_buff *skb;
+
+ /* sk is marked const to clearly express we dont hold socket lock.
+ * sock_wmalloc() will atomically change sk->sk_wmem_alloc,
+ * it is safe to promote sk to non const.
+ */
+ skb = sock_wmalloc((struct sock *)sk, MAX_DCCP_HEADER, 1,
+ GFP_ATOMIC);
+ if (!skb)
return NULL;
- /* Reserve space for headers. */
- skb_reserve(skb, sk->sk_prot->max_header);
+ skb_reserve(skb, MAX_DCCP_HEADER);
skb_dst_set(skb, dst_clone(dst));