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Message-Id: <8fcb0ad6f324008ccadfd1811d91b3145bbf95fd.1605175834.git.pabeni@redhat.com>
Date: Thu, 12 Nov 2020 11:47:59 +0100
From: Paolo Abeni <pabeni@...hat.com>
To: netdev@...r.kernel.org
Cc: Eric Dumazet <edumazet@...gle.com>, mptcp@...ts.01.org,
Jakub Kicinski <kuba@...nel.org>
Subject: [PATCH net-next 01/13] 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: Paolo Abeni <pabeni@...hat.com>
---
include/net/tcp.h | 3 ++
net/ipv4/tcp.c | 119 ++++++++++++++++++++++++++--------------------
2 files changed, 70 insertions(+), 52 deletions(-)
diff --git a/include/net/tcp.h b/include/net/tcp.h
index 4aba0f069b05..374d0a2acc4b 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -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);
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index b2bc3d7fe9e8..391705aaa80e 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -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);
@@ -964,6 +964,68 @@ static void tcp_remove_empty_skb(struct sock *sk, struct sk_buff *skb)
}
}
+struct sk_buff *tcp_build_frag(struct sock *sk, int size_goal, int flags,
+ struct page *page, int offset, size_t *size)
+{
+ struct sk_buff *skb = tcp_write_queue_tail(sk);
+ 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))
+ return NULL;
+
+ skb = sk_stream_alloc_skb(sk, 0, sk->sk_allocation,
+ tcp_rtx_and_write_queues_empty(sk));
+ if (!skb)
+ return NULL;
+
+#ifdef CONFIG_TLS_DEVICE
+ skb->decrypted = !!(flags & MSG_SENDPAGE_DECRYPTED);
+#endif
+ skb_entail(sk, skb);
+ copy = size_goal;
+ }
+
+ if (copy > *size)
+ copy = *size;
+
+ i = skb_shinfo(skb)->nr_frags;
+ can_coalesce = skb_can_coalesce(skb, i, page, offset);
+ if (!can_coalesce && i >= sysctl_max_skb_frags) {
+ tcp_mark_push(tp, skb);
+ goto new_segment;
+ }
+ if (!sk_wmem_schedule(sk, copy))
+ return NULL;
+
+ if (can_coalesce) {
+ skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
+ } else {
+ get_page(page);
+ skb_fill_page_desc(skb, i, page, offset, copy);
+ }
+
+ if (!(flags & MSG_NO_SHARED_FRAGS))
+ skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG;
+
+ skb->len += copy;
+ skb->data_len += copy;
+ skb->truesize += copy;
+ sk_wmem_queued_add(sk, copy);
+ sk_mem_charge(sk, copy);
+ skb->ip_summed = CHECKSUM_PARTIAL;
+ WRITE_ONCE(tp->write_seq, tp->write_seq + copy);
+ 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)
{
@@ -999,60 +1061,13 @@ ssize_t do_tcp_sendpages(struct sock *sk, struct page *page, int offset,
goto out_err;
while (size > 0) {
- struct sk_buff *skb = tcp_write_queue_tail(sk);
- int copy, i;
- bool can_coalesce;
-
- 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;
-
- skb = sk_stream_alloc_skb(sk, 0, sk->sk_allocation,
- tcp_rtx_and_write_queues_empty(sk));
- if (!skb)
- goto wait_for_space;
-
-#ifdef CONFIG_TLS_DEVICE
- skb->decrypted = !!(flags & MSG_SENDPAGE_DECRYPTED);
-#endif
- skb_entail(sk, skb);
- copy = size_goal;
- }
+ struct sk_buff *skb;
+ size_t copy = size;
- if (copy > size)
- copy = size;
-
- i = skb_shinfo(skb)->nr_frags;
- can_coalesce = skb_can_coalesce(skb, i, page, offset);
- if (!can_coalesce && i >= sysctl_max_skb_frags) {
- tcp_mark_push(tp, skb);
- goto new_segment;
- }
- if (!sk_wmem_schedule(sk, copy))
+ skb = tcp_build_frag(sk, size_goal, flags, page, offset, ©);
+ if (!skb)
goto wait_for_space;
- if (can_coalesce) {
- skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
- } else {
- get_page(page);
- skb_fill_page_desc(skb, i, page, offset, copy);
- }
-
- if (!(flags & MSG_NO_SHARED_FRAGS))
- skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG;
-
- skb->len += copy;
- skb->data_len += copy;
- skb->truesize += copy;
- sk_wmem_queued_add(sk, copy);
- sk_mem_charge(sk, copy);
- skb->ip_summed = CHECKSUM_PARTIAL;
- WRITE_ONCE(tp->write_seq, tp->write_seq + copy);
- TCP_SKB_CB(skb)->end_seq += copy;
- tcp_skb_pcount_set(skb, 0);
-
if (!copied)
TCP_SKB_CB(skb)->tcp_flags &= ~TCPHDR_PSH;
--
2.26.2
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