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Date: Thu, 11 Feb 2021 15:30:41 -0800
From: Mat Martineau <mathew.j.martineau@...ux.intel.com>
To: netdev@...r.kernel.org
Cc: Paolo Abeni <pabeni@...hat.com>, davem@...emloft.net,
kuba@...nel.org, mptcp@...ts.01.org, matthieu.baerts@...sares.net,
Mat Martineau <mathew.j.martineau@...ux.intel.com>
Subject: [PATCH net 5/6] mptcp: better msk receive window updates
From: Paolo Abeni <pabeni@...hat.com>
Move mptcp_cleanup_rbuf() related checks inside the mentioned
helper and extend them to mirror TCP checks more closely.
Additionally drop the 'rmem_pending' hack, since commit 879526030c8b
("mptcp: protect the rx path with the msk socket spinlock") we
can use instead 'rmem_released'.
Fixes: ea4ca586b16f ("mptcp: refine MPTCP-level ack scheduling")
Signed-off-by: Paolo Abeni <pabeni@...hat.com>
Signed-off-by: Mat Martineau <mathew.j.martineau@...ux.intel.com>
---
net/mptcp/options.c | 7 ++++---
net/mptcp/protocol.c | 38 ++++++++++++++++++++++----------------
net/mptcp/protocol.h | 3 +--
3 files changed, 27 insertions(+), 21 deletions(-)
diff --git a/net/mptcp/options.c b/net/mptcp/options.c
index e0d21c0607e5..82a37cc26776 100644
--- a/net/mptcp/options.c
+++ b/net/mptcp/options.c
@@ -498,8 +498,8 @@ static bool mptcp_established_options_dss(struct sock *sk, struct sk_buff *skb,
{
struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
struct mptcp_sock *msk = mptcp_sk(subflow->conn);
+ u64 snd_data_fin_enable, ack_seq;
unsigned int dss_size = 0;
- u64 snd_data_fin_enable;
struct mptcp_ext *mpext;
unsigned int ack_size;
bool ret = false;
@@ -531,13 +531,14 @@ static bool mptcp_established_options_dss(struct sock *sk, struct sk_buff *skb,
return ret;
}
+ ack_seq = READ_ONCE(msk->ack_seq);
if (READ_ONCE(msk->use_64bit_ack)) {
ack_size = TCPOLEN_MPTCP_DSS_ACK64;
- opts->ext_copy.data_ack = READ_ONCE(msk->ack_seq);
+ opts->ext_copy.data_ack = ack_seq;
opts->ext_copy.ack64 = 1;
} else {
ack_size = TCPOLEN_MPTCP_DSS_ACK32;
- opts->ext_copy.data_ack32 = (uint32_t)READ_ONCE(msk->ack_seq);
+ opts->ext_copy.data_ack32 = (uint32_t)ack_seq;
opts->ext_copy.ack64 = 0;
}
opts->ext_copy.use_ack = 1;
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index c11fcf6f5faf..0dbf5cbd7e56 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -457,7 +457,18 @@ static bool mptcp_subflow_cleanup_rbuf(struct sock *ssk)
static void mptcp_cleanup_rbuf(struct mptcp_sock *msk)
{
struct sock *ack_hint = READ_ONCE(msk->ack_hint);
+ int old_space = READ_ONCE(msk->old_wspace);
struct mptcp_subflow_context *subflow;
+ struct sock *sk = (struct sock *)msk;
+ bool cleanup;
+
+ /* this is a simple superset of what tcp_cleanup_rbuf() implements
+ * so that we don't have to acquire the ssk socket lock most of the time
+ * to do actually nothing
+ */
+ cleanup = __mptcp_space(sk) - old_space >= max(0, old_space);
+ if (!cleanup)
+ return;
/* if the hinted ssk is still active, try to use it */
if (likely(ack_hint)) {
@@ -1865,7 +1876,7 @@ static void __mptcp_splice_receive_queue(struct sock *sk)
skb_queue_splice_tail_init(&sk->sk_receive_queue, &msk->receive_queue);
}
-static bool __mptcp_move_skbs(struct mptcp_sock *msk, unsigned int rcv)
+static bool __mptcp_move_skbs(struct mptcp_sock *msk)
{
struct sock *sk = (struct sock *)msk;
unsigned int moved = 0;
@@ -1885,13 +1896,10 @@ static bool __mptcp_move_skbs(struct mptcp_sock *msk, unsigned int rcv)
slowpath = lock_sock_fast(ssk);
mptcp_data_lock(sk);
+ __mptcp_update_rmem(sk);
done = __mptcp_move_skbs_from_subflow(msk, ssk, &moved);
mptcp_data_unlock(sk);
- if (moved && rcv) {
- WRITE_ONCE(msk->rmem_pending, min(rcv, moved));
- tcp_cleanup_rbuf(ssk, 1);
- WRITE_ONCE(msk->rmem_pending, 0);
- }
+ tcp_cleanup_rbuf(ssk, moved);
unlock_sock_fast(ssk, slowpath);
} while (!done);
@@ -1904,6 +1912,7 @@ static bool __mptcp_move_skbs(struct mptcp_sock *msk, unsigned int rcv)
ret |= __mptcp_ofo_queue(msk);
__mptcp_splice_receive_queue(sk);
mptcp_data_unlock(sk);
+ mptcp_cleanup_rbuf(msk);
}
if (ret)
mptcp_check_data_fin((struct sock *)msk);
@@ -1933,7 +1942,7 @@ static int mptcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
target = sock_rcvlowat(sk, flags & MSG_WAITALL, len);
while (copied < len) {
- int bytes_read, old_space;
+ int bytes_read;
bytes_read = __mptcp_recvmsg_mskq(msk, msg, len - copied);
if (unlikely(bytes_read < 0)) {
@@ -1944,14 +1953,11 @@ static int mptcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
copied += bytes_read;
- if (skb_queue_empty(&msk->receive_queue) &&
- __mptcp_move_skbs(msk, len - copied))
- continue;
-
/* be sure to advertise window change */
- old_space = READ_ONCE(msk->old_wspace);
- if ((tcp_space(sk) - old_space) >= old_space)
- mptcp_cleanup_rbuf(msk);
+ mptcp_cleanup_rbuf(msk);
+
+ if (skb_queue_empty(&msk->receive_queue) && __mptcp_move_skbs(msk))
+ continue;
/* only the master socket status is relevant here. The exit
* conditions mirror closely tcp_recvmsg()
@@ -1979,7 +1985,7 @@ static int mptcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
/* race breaker: the shutdown could be after the
* previous receive queue check
*/
- if (__mptcp_move_skbs(msk, len - copied))
+ if (__mptcp_move_skbs(msk))
continue;
break;
}
@@ -2012,7 +2018,7 @@ static int mptcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
/* .. race-breaker: ssk might have gotten new data
* after last __mptcp_move_skbs() returned false.
*/
- if (unlikely(__mptcp_move_skbs(msk, 0)))
+ if (unlikely(__mptcp_move_skbs(msk)))
set_bit(MPTCP_DATA_READY, &msk->flags);
} else if (unlikely(!test_bit(MPTCP_DATA_READY, &msk->flags))) {
/* data to read but mptcp_wait_data() cleared DATA_READY */
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index 6a164add5b6f..8d9f0ff10cb8 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -234,7 +234,6 @@ struct mptcp_sock {
u64 wnd_end;
unsigned long timer_ival;
u32 token;
- int rmem_pending;
int rmem_released;
unsigned long flags;
bool can_ack;
@@ -293,7 +292,7 @@ static inline struct mptcp_sock *mptcp_sk(const struct sock *sk)
static inline int __mptcp_space(const struct sock *sk)
{
- return tcp_space(sk) + READ_ONCE(mptcp_sk(sk)->rmem_pending);
+ return tcp_space(sk) + READ_ONCE(mptcp_sk(sk)->rmem_released);
}
static inline struct mptcp_data_frag *mptcp_send_head(const struct sock *sk)
--
2.30.1
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