diff options
| author | David S. Miller <davem@davemloft.net> | 2015-09-25 13:00:40 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2015-09-25 13:00:40 -0700 |
| commit | 4d54d86546f62c7c4a0fe3b36a64c5e3b98ce1a9 (patch) | |
| tree | bd48e072bacebb47bc6cd4ebb3483e9bd9da21b0 /net/dccp/output.c | |
| parent | 6ea29da1d04f56e167ec8cc5ed15e927997d9d67 (diff) | |
| parent | 1b70e977cef6ce7e7411c9bbec21f9adc8e29097 (diff) | |
Merge branch 'listener-sock-const'
Eric Dumazet says:
====================
dccp/tcp: constify listener sock
Another patch bomb to prepare lockless TCP/DCCP LISTEN handling.
SYNACK retransmits are built and sent without listener socket
being locked. Soon, initial SYNACK packets will have same property.
This series makes sure we did not something wrong with this model,
by adding a const qualifier in all the paths taken from synack building
and transmit, for IPv4/IPv6 and TCP/dccp.
The only potential problem was the rewrite of ecn bits for connections
with DCTCP as congestion module, but this was a very minor one.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/dccp/output.c')
| -rw-r--r-- | net/dccp/output.c | 17 |
1 files changed, 11 insertions, 6 deletions
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)); |