Commit b796d04b authored by Paolo Abeni's avatar Paolo Abeni Committed by Jakub Kicinski
Browse files

tcp: factor out tcp_build_frag() 



Will be needed by the next patch, as MPTCP needs to handle
directly the error/memory-allocation-needed path.

No functional changes intended.

Additionally let MPTCP code access the tcp_remove_empty_skb()
helper.

Signed-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent c0a645a7

include/net/tcp.h

+3 −0
Original line number Diff line number Diff line
@@ -322,6 +322,7 @@ void tcp_shutdown(struct sock *sk, int how); 
int tcp_v4_early_demux(struct sk_buff *skb);

int tcp_v4_rcv(struct sk_buff *skb);



void tcp_remove_empty_skb(struct sock *sk, struct sk_buff *skb);

int tcp_v4_tw_remember_stamp(struct inet_timewait_sock *tw);

int tcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t size);

int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size);
@@ -329,6 +330,8 @@ int tcp_sendpage(struct sock *sk, struct page *page, int offset, size_t size, 
		 int flags);

int tcp_sendpage_locked(struct sock *sk, struct page *page, int offset,

			size_t size, int flags);

struct sk_buff *tcp_build_frag(struct sock *sk, int size_goal, int flags,

			       struct page *page, int offset, size_t *size);

ssize_t do_tcp_sendpages(struct sock *sk, struct page *page, int offset,

		 size_t size, int flags);

int tcp_send_mss(struct sock *sk, int *size_goal, int flags);

net/ipv4/tcp.c

+67 −52
Original line number Diff line number Diff line
@@ -954,7 +954,7 @@ int tcp_send_mss(struct sock *sk, int *size_goal, int flags) 
 * importantly be able to generate EPOLLOUT for Edge Trigger epoll()

 * users.

 */

static void tcp_remove_empty_skb(struct sock *sk, struct sk_buff *skb)

void tcp_remove_empty_skb(struct sock *sk, struct sk_buff *skb)

{

	if (skb && !skb->len) {

		tcp_unlink_write_queue(skb, sk);
@@ -964,55 +964,24 @@ static void tcp_remove_empty_skb(struct sock *sk, struct sk_buff *skb) 
	}

}



ssize_t do_tcp_sendpages(struct sock *sk, struct page *page, int offset,

			 size_t size, int flags)

struct sk_buff *tcp_build_frag(struct sock *sk, int size_goal, int flags,

			       struct page *page, int offset, size_t *size)

{

	struct tcp_sock *tp = tcp_sk(sk);

	int mss_now, size_goal;

	int err;

	ssize_t copied;

	long timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);



	if (IS_ENABLED(CONFIG_DEBUG_VM) &&

	    WARN_ONCE(!sendpage_ok(page),

		      "page must not be a Slab one and have page_count > 0"))

		return -EINVAL;



	/* Wait for a connection to finish. One exception is TCP Fast Open

	 * (passive side) where data is allowed to be sent before a connection

	 * is fully established.

	 */

	if (((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) &&

	    !tcp_passive_fastopen(sk)) {

		err = sk_stream_wait_connect(sk, &timeo);

		if (err != 0)

			goto out_err;

	}



	sk_clear_bit(SOCKWQ_ASYNC_NOSPACE, sk);



	mss_now = tcp_send_mss(sk, &size_goal, flags);

	copied = 0;



	err = -EPIPE;

	if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))

		goto out_err;



	while (size > 0) {

	struct sk_buff *skb = tcp_write_queue_tail(sk);

		int copy, i;

	struct tcp_sock *tp = tcp_sk(sk);

	bool can_coalesce;

	int copy, i;



	if (!skb || (copy = size_goal - skb->len) <= 0 ||

	    !tcp_skb_can_collapse_to(skb)) {

new_segment:

		if (!sk_stream_memory_free(sk))

				goto wait_for_space;

			return NULL;



		skb = sk_stream_alloc_skb(sk, 0, sk->sk_allocation,

					  tcp_rtx_and_write_queues_empty(sk));

		if (!skb)

				goto wait_for_space;

			return NULL;



#ifdef CONFIG_TLS_DEVICE

		skb->decrypted = !!(flags & MSG_SENDPAGE_DECRYPTED);
@@ -1021,8 +990,8 @@ new_segment: 
		copy = size_goal;

	}



		if (copy > size)

			copy = size;

	if (copy > *size)

		copy = *size;



	i = skb_shinfo(skb)->nr_frags;

	can_coalesce = skb_can_coalesce(skb, i, page, offset);
@@ -1031,7 +1000,7 @@ new_segment: 
		goto new_segment;

	}

	if (!sk_wmem_schedule(sk, copy))

			goto wait_for_space;

		return NULL;



	if (can_coalesce) {

		skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
@@ -1053,6 +1022,52 @@ new_segment: 
	TCP_SKB_CB(skb)->end_seq += copy;

	tcp_skb_pcount_set(skb, 0);



	*size = copy;

	return skb;

}



ssize_t do_tcp_sendpages(struct sock *sk, struct page *page, int offset,

			 size_t size, int flags)

{

	struct tcp_sock *tp = tcp_sk(sk);

	int mss_now, size_goal;

	int err;

	ssize_t copied;

	long timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);



	if (IS_ENABLED(CONFIG_DEBUG_VM) &&

	    WARN_ONCE(!sendpage_ok(page),

		      "page must not be a Slab one and have page_count > 0"))

		return -EINVAL;



	/* Wait for a connection to finish. One exception is TCP Fast Open

	 * (passive side) where data is allowed to be sent before a connection

	 * is fully established.

	 */

	if (((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) &&

	    !tcp_passive_fastopen(sk)) {

		err = sk_stream_wait_connect(sk, &timeo);

		if (err != 0)

			goto out_err;

	}



	sk_clear_bit(SOCKWQ_ASYNC_NOSPACE, sk);



	mss_now = tcp_send_mss(sk, &size_goal, flags);

	copied = 0;



	err = -EPIPE;

	if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))

		goto out_err;



	while (size > 0) {

		struct sk_buff *skb;

		size_t copy = size;



		skb = tcp_build_frag(sk, size_goal, flags, page, offset, &copy);

		if (!skb)

			goto wait_for_space;



		if (!copied)

			TCP_SKB_CB(skb)->tcp_flags &= ~TCPHDR_PSH;

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