* [PATCH net-next 1/2] mptcp: create msk early
2020-03-12 15:13 [PATCH net-next 0/2] mptcp: simplify mptcp_accept() Paolo Abeni
@ 2020-03-12 15:13 ` Paolo Abeni
2020-03-12 15:13 ` [PATCH net-next 2/2] mptcp: drop unneeded checks Paolo Abeni
2020-03-13 14:09 ` [PATCH net-next 0/2] mptcp: simplify mptcp_accept() Paolo Abeni
2 siblings, 0 replies; 4+ messages in thread
From: Paolo Abeni @ 2020-03-12 15:13 UTC (permalink / raw)
To: netdev; +Cc: davem, Mat Martineau
This change move the mptcp socket allocation from mptcp_accept() to
subflow_syn_recv_sock(), so that subflow->conn is now always set
for the non fallback scenario.
It allows cleaning up a bit mptcp_accept() reducing the additional
locking and will allow fourther cleanup in later patch
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
---
net/mptcp/protocol.c | 83 ++++++++++++++++++++++++--------------------
net/mptcp/protocol.h | 4 +--
net/mptcp/subflow.c | 32 +++++++++++------
net/mptcp/token.c | 31 ++---------------
4 files changed, 70 insertions(+), 80 deletions(-)
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index c0cef07f4382..04c3caed92df 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -820,9 +820,12 @@ static struct ipv6_pinfo *mptcp_inet6_sk(const struct sock *sk)
}
#endif
-static struct sock *mptcp_sk_clone_lock(const struct sock *sk)
+struct sock *mptcp_sk_clone(const struct sock *sk, struct request_sock *req)
{
+ struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req);
struct sock *nsk = sk_clone_lock(sk, GFP_ATOMIC);
+ struct mptcp_sock *msk;
+ u64 ack_seq;
if (!nsk)
return NULL;
@@ -832,6 +835,36 @@ static struct sock *mptcp_sk_clone_lock(const struct sock *sk)
inet_sk(nsk)->pinet6 = mptcp_inet6_sk(nsk);
#endif
+ __mptcp_init_sock(nsk);
+
+ msk = mptcp_sk(nsk);
+ msk->local_key = subflow_req->local_key;
+ msk->token = subflow_req->token;
+ msk->subflow = NULL;
+
+ if (unlikely(mptcp_token_new_accept(subflow_req->token, nsk))) {
+ bh_unlock_sock(nsk);
+
+ /* we can't call into mptcp_close() here - possible BH context
+ * free the sock directly
+ */
+ nsk->sk_prot->destroy(nsk);
+ sk_free(nsk);
+ return NULL;
+ }
+
+ msk->write_seq = subflow_req->idsn + 1;
+ if (subflow_req->remote_key_valid) {
+ msk->can_ack = true;
+ msk->remote_key = subflow_req->remote_key;
+ mptcp_crypto_key_sha(msk->remote_key, NULL, &ack_seq);
+ ack_seq++;
+ msk->ack_seq = ack_seq;
+ }
+ bh_unlock_sock(nsk);
+
+ /* keep a single reference */
+ __sock_put(nsk);
return nsk;
}
@@ -859,40 +892,26 @@ static struct sock *mptcp_accept(struct sock *sk, int flags, int *err,
struct mptcp_subflow_context *subflow;
struct sock *new_mptcp_sock;
struct sock *ssk = newsk;
- u64 ack_seq;
subflow = mptcp_subflow_ctx(newsk);
- lock_sock(sk);
+ new_mptcp_sock = subflow->conn;
- local_bh_disable();
- new_mptcp_sock = mptcp_sk_clone_lock(sk);
- if (!new_mptcp_sock) {
- *err = -ENOBUFS;
- local_bh_enable();
- release_sock(sk);
- mptcp_subflow_shutdown(newsk, SHUT_RDWR + 1, 0, 0);
- tcp_close(newsk, 0);
- return NULL;
+ /* is_mptcp should be false if subflow->conn is missing, see
+ * subflow_syn_recv_sock()
+ */
+ if (WARN_ON_ONCE(!new_mptcp_sock)) {
+ tcp_sk(newsk)->is_mptcp = 0;
+ return newsk;
}
- __mptcp_init_sock(new_mptcp_sock);
+ /* acquire the 2nd reference for the owning socket */
+ sock_hold(new_mptcp_sock);
+ local_bh_disable();
+ bh_lock_sock(new_mptcp_sock);
msk = mptcp_sk(new_mptcp_sock);
- msk->local_key = subflow->local_key;
- msk->token = subflow->token;
- msk->subflow = NULL;
msk->first = newsk;
- mptcp_token_update_accept(newsk, new_mptcp_sock);
-
- msk->write_seq = subflow->idsn + 1;
- if (subflow->can_ack) {
- msk->can_ack = true;
- msk->remote_key = subflow->remote_key;
- mptcp_crypto_key_sha(msk->remote_key, NULL, &ack_seq);
- ack_seq++;
- msk->ack_seq = ack_seq;
- }
newsk = new_mptcp_sock;
mptcp_copy_inaddrs(newsk, ssk);
list_add(&subflow->node, &msk->conn_list);
@@ -903,18 +922,6 @@ static struct sock *mptcp_accept(struct sock *sk, int flags, int *err,
inet_sk_state_store(new_mptcp_sock, TCP_SYN_RECV);
bh_unlock_sock(new_mptcp_sock);
local_bh_enable();
- release_sock(sk);
-
- /* the subflow can already receive packet, avoid racing with
- * the receive path and process the pending ones
- */
- lock_sock(ssk);
- subflow->rel_write_seq = 1;
- subflow->tcp_sock = ssk;
- subflow->conn = new_mptcp_sock;
- if (unlikely(!skb_queue_empty(&ssk->sk_receive_queue)))
- mptcp_subflow_data_available(ssk);
- release_sock(ssk);
}
return newsk;
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index 313558fa8185..9baf6fcba914 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -193,6 +193,7 @@ void mptcp_proto_init(void);
int mptcp_proto_v6_init(void);
#endif
+struct sock *mptcp_sk_clone(const struct sock *sk, struct request_sock *req);
void mptcp_get_options(const struct sk_buff *skb,
struct tcp_options_received *opt_rx);
@@ -202,8 +203,7 @@ void mptcp_data_ready(struct sock *sk, struct sock *ssk);
int mptcp_token_new_request(struct request_sock *req);
void mptcp_token_destroy_request(u32 token);
int mptcp_token_new_connect(struct sock *sk);
-int mptcp_token_new_accept(u32 token);
-void mptcp_token_update_accept(struct sock *sk, struct sock *conn);
+int mptcp_token_new_accept(u32 token, struct sock *conn);
void mptcp_token_destroy(u32 token);
void mptcp_crypto_key_sha(u64 key, u32 *token, u64 *idsn);
diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c
index 0de2a44bdaa0..047b088e4617 100644
--- a/net/mptcp/subflow.c
+++ b/net/mptcp/subflow.c
@@ -182,6 +182,7 @@ static struct sock *subflow_syn_recv_sock(const struct sock *sk,
struct mptcp_subflow_context *listener = mptcp_subflow_ctx(sk);
struct mptcp_subflow_request_sock *subflow_req;
struct tcp_options_received opt_rx;
+ struct sock *new_msk = NULL;
struct sock *child;
pr_debug("listener=%p, req=%p, conn=%p", listener, req, listener->conn);
@@ -197,7 +198,7 @@ static struct sock *subflow_syn_recv_sock(const struct sock *sk,
* out-of-order pkt, which will not carry the MP_CAPABLE
* opt even on mptcp enabled paths
*/
- goto create_child;
+ goto create_msk;
}
opt_rx.mptcp.mp_capable = 0;
@@ -207,7 +208,13 @@ static struct sock *subflow_syn_recv_sock(const struct sock *sk,
subflow_req->remote_key_valid = 1;
} else {
subflow_req->mp_capable = 0;
+ goto create_child;
}
+
+create_msk:
+ new_msk = mptcp_sk_clone(listener->conn, req);
+ if (!new_msk)
+ subflow_req->mp_capable = 0;
}
create_child:
@@ -221,22 +228,22 @@ static struct sock *subflow_syn_recv_sock(const struct sock *sk,
* handshake
*/
if (!ctx)
- return child;
+ goto out;
if (ctx->mp_capable) {
- if (mptcp_token_new_accept(ctx->token))
- goto close_child;
+ /* new mpc subflow takes ownership of the newly
+ * created mptcp socket
+ */
+ ctx->conn = new_msk;
+ new_msk = NULL;
}
}
+out:
+ /* dispose of the left over mptcp master, if any */
+ if (unlikely(new_msk))
+ sock_put(new_msk);
return child;
-
-close_child:
- pr_debug("closing child socket");
- tcp_send_active_reset(child, GFP_ATOMIC);
- inet_csk_prepare_forced_close(child);
- tcp_done(child);
- return NULL;
}
static struct inet_connection_sock_af_ops subflow_specific;
@@ -793,6 +800,9 @@ static void subflow_ulp_clone(const struct request_sock *req,
new_ctx->tcp_data_ready = old_ctx->tcp_data_ready;
new_ctx->tcp_state_change = old_ctx->tcp_state_change;
new_ctx->tcp_write_space = old_ctx->tcp_write_space;
+ new_ctx->rel_write_seq = 1;
+ new_ctx->tcp_sock = newsk;
+
new_ctx->mp_capable = 1;
new_ctx->fourth_ack = subflow_req->remote_key_valid;
new_ctx->can_ack = subflow_req->remote_key_valid;
diff --git a/net/mptcp/token.c b/net/mptcp/token.c
index 84d887806090..b71b53c0ac8d 100644
--- a/net/mptcp/token.c
+++ b/net/mptcp/token.c
@@ -128,45 +128,18 @@ int mptcp_token_new_connect(struct sock *sk)
*
* Called when a SYN packet creates a new logical connection, i.e.
* is not a join request.
- *
- * We don't have an mptcp socket yet at that point.
- * This is paired with mptcp_token_update_accept, called on accept().
*/
-int mptcp_token_new_accept(u32 token)
+int mptcp_token_new_accept(u32 token, struct sock *conn)
{
int err;
spin_lock_bh(&token_tree_lock);
- err = radix_tree_insert(&token_tree, token, &token_used);
+ err = radix_tree_insert(&token_tree, token, conn);
spin_unlock_bh(&token_tree_lock);
return err;
}
-/**
- * mptcp_token_update_accept - update token to map to mptcp socket
- * @conn: the new struct mptcp_sock
- * @sk: the initial subflow for this mptcp socket
- *
- * Called when the first mptcp socket is created on accept to
- * refresh the dummy mapping (done to reserve the token) with
- * the mptcp_socket structure that wasn't allocated before.
- */
-void mptcp_token_update_accept(struct sock *sk, struct sock *conn)
-{
- struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
- void __rcu **slot;
-
- spin_lock_bh(&token_tree_lock);
- slot = radix_tree_lookup_slot(&token_tree, subflow->token);
- WARN_ON_ONCE(!slot);
- if (slot) {
- WARN_ON_ONCE(rcu_access_pointer(*slot) != &token_used);
- radix_tree_replace_slot(&token_tree, slot, conn);
- }
- spin_unlock_bh(&token_tree_lock);
-}
-
/**
* mptcp_token_destroy_request - remove mptcp connection/token
* @token - token of mptcp connection to remove
--
2.21.1
^ permalink raw reply related [flat|nested] 4+ messages in thread* [PATCH net-next 2/2] mptcp: drop unneeded checks
2020-03-12 15:13 [PATCH net-next 0/2] mptcp: simplify mptcp_accept() Paolo Abeni
2020-03-12 15:13 ` [PATCH net-next 1/2] mptcp: create msk early Paolo Abeni
@ 2020-03-12 15:13 ` Paolo Abeni
2020-03-13 14:09 ` [PATCH net-next 0/2] mptcp: simplify mptcp_accept() Paolo Abeni
2 siblings, 0 replies; 4+ messages in thread
From: Paolo Abeni @ 2020-03-12 15:13 UTC (permalink / raw)
To: netdev; +Cc: davem, Mat Martineau
After the previous patch subflow->conn is always != NULL and
is never changed. We can drop a bunch of now unneeded checks
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
---
net/mptcp/options.c | 2 +-
net/mptcp/subflow.c | 18 +++++++-----------
2 files changed, 8 insertions(+), 12 deletions(-)
diff --git a/net/mptcp/options.c b/net/mptcp/options.c
index b9a8305bd934..eb6cd0accf99 100644
--- a/net/mptcp/options.c
+++ b/net/mptcp/options.c
@@ -362,7 +362,7 @@ static bool mptcp_established_options_dss(struct sock *sk, struct sk_buff *skb,
opts->ext_copy.use_ack = 0;
msk = mptcp_sk(subflow->conn);
- if (!msk || !READ_ONCE(msk->can_ack)) {
+ if (!READ_ONCE(msk->can_ack)) {
*size = ALIGN(dss_size, 4);
return ret;
}
diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c
index 047b088e4617..8434c7f5f712 100644
--- a/net/mptcp/subflow.c
+++ b/net/mptcp/subflow.c
@@ -112,7 +112,7 @@ static void subflow_finish_connect(struct sock *sk, const struct sk_buff *skb)
subflow->icsk_af_ops->sk_rx_dst_set(sk, skb);
- if (subflow->conn && !subflow->conn_finished) {
+ if (!subflow->conn_finished) {
pr_debug("subflow=%p, remote_key=%llu", mptcp_subflow_ctx(sk),
subflow->remote_key);
mptcp_finish_connect(sk);
@@ -439,9 +439,6 @@ static bool subflow_check_data_avail(struct sock *ssk)
if (subflow->data_avail)
return true;
- if (!subflow->conn)
- return false;
-
msk = mptcp_sk(subflow->conn);
for (;;) {
u32 map_remaining;
@@ -561,11 +558,10 @@ static void subflow_data_ready(struct sock *sk)
struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
struct sock *parent = subflow->conn;
- if (!parent || !subflow->mp_capable) {
+ if (!subflow->mp_capable) {
subflow->tcp_data_ready(sk);
- if (parent)
- parent->sk_data_ready(parent);
+ parent->sk_data_ready(parent);
return;
}
@@ -579,7 +575,7 @@ static void subflow_write_space(struct sock *sk)
struct sock *parent = subflow->conn;
sk_stream_write_space(sk);
- if (parent && sk_stream_is_writeable(sk)) {
+ if (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 */
@@ -694,7 +690,7 @@ static bool subflow_is_done(const struct sock *sk)
static void subflow_state_change(struct sock *sk)
{
struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
- struct sock *parent = READ_ONCE(subflow->conn);
+ struct sock *parent = subflow->conn;
__subflow_state_change(sk);
@@ -702,10 +698,10 @@ static void subflow_state_change(struct sock *sk)
* a fin packet carrying a DSS can be unnoticed if we don't trigger
* the data available machinery here.
*/
- if (parent && subflow->mp_capable && mptcp_subflow_data_available(sk))
+ if (subflow->mp_capable && mptcp_subflow_data_available(sk))
mptcp_data_ready(parent, sk);
- if (parent && !(parent->sk_shutdown & RCV_SHUTDOWN) &&
+ if (!(parent->sk_shutdown & RCV_SHUTDOWN) &&
!subflow->rx_eof && subflow_is_done(sk)) {
subflow->rx_eof = 1;
parent->sk_shutdown |= RCV_SHUTDOWN;
--
2.21.1
^ permalink raw reply related [flat|nested] 4+ messages in thread