mptcp: avoid atomic bit manipulation when possible

Currently the msk->flags bitmask carries both state for the
mptcp_release_cb() - mostly touched under the mptcp data lock
- and others state info touched even outside such lock scope.

As a consequence, msk->flags is always manipulated with
atomic operations.

This change splits such bitmask in two separate fields, so
that we use plain bit operations when touching the
cb-related info.

The MPTCP_PUSH_PENDING bit needs additional care, as it is the
only CB related field currently accessed either under the mptcp
data lock or the mptcp socket lock.
Let's add another mask just for such bit's sake.

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 2 deletions

diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c
index a1cd39f97659..5bedc7e88977 100644
--- a/net/mptcp/subflow.c
+++ b/net/mptcp/subflow.c
@@ -388,7 +388,7 @@ static void mptcp_set_connected(struct sock *sk)
 	if (!sock_owned_by_user(sk))
 		__mptcp_set_connected(sk);
 	else
-		set_bit(MPTCP_CONNECTED, &mptcp_sk(sk)->flags);
+		__set_bit(MPTCP_CONNECTED, &mptcp_sk(sk)->cb_flags);
 	mptcp_data_unlock(sk);
 }
 
@@ -1274,7 +1274,7 @@ static void subflow_error_report(struct sock *ssk)
 	if (!sock_owned_by_user(sk))
 		__mptcp_error_report(sk);
 	else
-		set_bit(MPTCP_ERROR_REPORT,  &mptcp_sk(sk)->flags);
+		__set_bit(MPTCP_ERROR_REPORT,  &mptcp_sk(sk)->cb_flags);
 	mptcp_data_unlock(sk);
 }