From 802885fc0400d0166a6b65d1844b61696aecbb10 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Fri, 25 Sep 2015 07:39:22 -0700 Subject: [PATCH] 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 Signed-off-by: David S. Miller --- net/dccp/dccp.h | 2 +- net/dccp/output.c | 17 +++++++++++------ 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)); -- 2.20.1