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Date: Tue, 21 Jan 2020 16:56:25 -0800
From: Christoph Paasch <cpaasch@...le.com>
To: netdev@...r.kernel.org
Cc: mptcp@...ts.01.org, Florian Westphal <fw@...len.de>,
Peter Krystad <peter.krystad@...ux.intel.com>
Subject: [PATCH net-next v3 11/19] mptcp: add subflow write space signalling
and mptcp_poll
From: Florian Westphal <fw@...len.de>
Add new SEND_SPACE flag to indicate that a subflow has enough space to
accept more data for transmission.
It gets cleared at the end of mptcp_sendmsg() in case ssk has run
below the free watermark.
It is (re-set) from the wspace callback.
This allows us to use msk->flags to determine the poll mask.
Co-developed-by: Peter Krystad <peter.krystad@...ux.intel.com>
Signed-off-by: Peter Krystad <peter.krystad@...ux.intel.com>
Signed-off-by: Florian Westphal <fw@...len.de>
Signed-off-by: Christoph Paasch <cpaasch@...le.com>
---
net/mptcp/protocol.c | 53 ++++++++++++++++++++++++++++++++++++++++++++
net/mptcp/protocol.h | 1 +
net/mptcp/subflow.c | 3 +++
3 files changed, 57 insertions(+)
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index 71250149180b..408efbe34753 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -176,6 +176,23 @@ static int mptcp_sendmsg_frag(struct sock *sk, struct sock *ssk,
return ret;
}
+static void ssk_check_wmem(struct mptcp_sock *msk, struct sock *ssk)
+{
+ struct socket *sock;
+
+ if (likely(sk_stream_is_writeable(ssk)))
+ return;
+
+ sock = READ_ONCE(ssk->sk_socket);
+
+ if (sock) {
+ clear_bit(MPTCP_SEND_SPACE, &msk->flags);
+ smp_mb__after_atomic();
+ /* set NOSPACE only after clearing SEND_SPACE flag */
+ set_bit(SOCK_NOSPACE, &sock->flags);
+ }
+}
+
static int mptcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
{
struct mptcp_sock *msk = mptcp_sk(sk);
@@ -219,6 +236,7 @@ static int mptcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
if (copied > 0)
ret = copied;
+ ssk_check_wmem(msk, ssk);
release_sock(ssk);
release_sock(sk);
return ret;
@@ -315,6 +333,7 @@ static int mptcp_init_sock(struct sock *sk)
struct mptcp_sock *msk = mptcp_sk(sk);
INIT_LIST_HEAD(&msk->conn_list);
+ __set_bit(MPTCP_SEND_SPACE, &msk->flags);
return 0;
}
@@ -576,6 +595,13 @@ static void mptcp_sock_graft(struct sock *sk, struct socket *parent)
write_unlock_bh(&sk->sk_callback_lock);
}
+static bool mptcp_memory_free(const struct sock *sk, int wake)
+{
+ struct mptcp_sock *msk = mptcp_sk(sk);
+
+ return wake ? test_bit(MPTCP_SEND_SPACE, &msk->flags) : true;
+}
+
static struct proto mptcp_prot = {
.name = "MPTCP",
.owner = THIS_MODULE,
@@ -591,6 +617,7 @@ static struct proto mptcp_prot = {
.hash = inet_hash,
.unhash = inet_unhash,
.get_port = mptcp_get_port,
+ .stream_memory_free = mptcp_memory_free,
.obj_size = sizeof(struct mptcp_sock),
.no_autobind = true,
};
@@ -767,8 +794,34 @@ static int mptcp_stream_accept(struct socket *sock, struct socket *newsock,
static __poll_t mptcp_poll(struct file *file, struct socket *sock,
struct poll_table_struct *wait)
{
+ const struct mptcp_sock *msk;
+ struct sock *sk = sock->sk;
+ struct socket *ssock;
__poll_t mask = 0;
+ msk = mptcp_sk(sk);
+ lock_sock(sk);
+ ssock = __mptcp_nmpc_socket(msk);
+ if (ssock) {
+ mask = ssock->ops->poll(file, ssock, wait);
+ release_sock(sk);
+ return mask;
+ }
+
+ release_sock(sk);
+ sock_poll_wait(file, sock, wait);
+ lock_sock(sk);
+
+ if (test_bit(MPTCP_DATA_READY, &msk->flags))
+ mask = EPOLLIN | EPOLLRDNORM;
+ if (sk_stream_is_writeable(sk) &&
+ test_bit(MPTCP_SEND_SPACE, &msk->flags))
+ mask |= EPOLLOUT | EPOLLWRNORM;
+ if (sk->sk_shutdown & RCV_SHUTDOWN)
+ mask |= EPOLLIN | EPOLLRDNORM | EPOLLRDHUP;
+
+ release_sock(sk);
+
return mask;
}
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index c6d8217e24d4..59a83eb64d37 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -56,6 +56,7 @@
/* MPTCP socket flags */
#define MPTCP_DATA_READY BIT(0)
+#define MPTCP_SEND_SPACE BIT(1)
/* MPTCP connection sock */
struct mptcp_sock {
diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c
index 528351e26371..9fb3eb87a20f 100644
--- a/net/mptcp/subflow.c
+++ b/net/mptcp/subflow.c
@@ -529,6 +529,9 @@ static void subflow_write_space(struct sock *sk)
sk_stream_write_space(sk);
if (parent && sk_stream_is_writeable(sk)) {
+ set_bit(MPTCP_SEND_SPACE, &mptcp_sk(parent)->flags);
+ smp_mb__after_atomic();
+ /* set SEND_SPACE before sk_stream_write_space clears NOSPACE */
sk_stream_write_space(parent);
}
}
--
2.23.0
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