Commit 99519122 authored by Xin Long's avatar Xin Long Committed by David S. Miller
Browse files

sctp: define sctp_packet_gso_append to build GSO frames 



Now sctp GSO uses skb_gro_receive() to append the data into head
skb frag_list. However it actually only needs very few code from
skb_gro_receive(). Besides, NAPI_GRO_CB has to be set while most
of its members are not needed here.

This patch is to add sctp_packet_gso_append() to build GSO frames
instead of skb_gro_receive(), and it would avoid many unnecessary
checks and make the code clearer.

Note that sctp will use page frags instead of frag_list to build
GSO frames in another patch. But it may take time, as sctp's GSO
frames may have different size. skb_segment() can only split it
into the frags with the same size, which would break the border
of sctp chunks.

Signed-off-by: default avatarXin Long <lucien.xin@gmail.com>
Reviewed-by: default avatarMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Acked-by: default avatarNeil Horman <nhorman@tuxdriver.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 60d061e3

include/net/sctp/structs.h

+5 −0
Original line number Diff line number Diff line
@@ -1133,6 +1133,11 @@ struct sctp_input_cb { 
};

#define SCTP_INPUT_CB(__skb)	((struct sctp_input_cb *)&((__skb)->cb[0]))



struct sctp_output_cb {

	struct sk_buff *last;

};

#define SCTP_OUTPUT_CB(__skb)	((struct sctp_output_cb *)&((__skb)->cb[0]))



static inline const struct sk_buff *sctp_gso_headskb(const struct sk_buff *skb)

{

	const struct sctp_chunk *chunk = SCTP_INPUT_CB(skb)->chunk;

net/sctp/output.c

+18 −10
Original line number Diff line number Diff line
@@ -409,6 +409,21 @@ static void sctp_packet_set_owner_w(struct sk_buff *skb, struct sock *sk) 
	refcount_inc(&sk->sk_wmem_alloc);

}



static void sctp_packet_gso_append(struct sk_buff *head, struct sk_buff *skb)

{

	if (SCTP_OUTPUT_CB(head)->last == head)

		skb_shinfo(head)->frag_list = skb;

	else

		SCTP_OUTPUT_CB(head)->last->next = skb;

	SCTP_OUTPUT_CB(head)->last = skb;



	head->truesize += skb->truesize;

	head->data_len += skb->len;

	head->len += skb->len;



	__skb_header_release(skb);

}



static int sctp_packet_pack(struct sctp_packet *packet,

			    struct sk_buff *head, int gso, gfp_t gfp)

{
@@ -422,7 +437,7 @@ static int sctp_packet_pack(struct sctp_packet *packet, 


	if (gso) {

		skb_shinfo(head)->gso_type = sk->sk_gso_type;

		NAPI_GRO_CB(head)->last = head;

		SCTP_OUTPUT_CB(head)->last = head;

	} else {

		nskb = head;

		pkt_size = packet->size;
@@ -503,15 +518,8 @@ merge: 
					 &packet->chunk_list);

		}



		if (gso) {

			if (skb_gro_receive(&head, nskb)) {

				kfree_skb(nskb);

				return 0;

			}

			if (WARN_ON_ONCE(skb_shinfo(head)->gso_segs >=

					 sk->sk_gso_max_segs))

				return 0;

		}

		if (gso)

			sctp_packet_gso_append(head, nskb);



		pkt_count++;

	} while (!list_empty(&packet->chunk_list));

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