Track the exceptional handling of MPTCP-level offered window
with a few more counters for observability.

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
---
 net/mptcp/mib.c     | 3 +++
 net/mptcp/mib.h     | 5 +++++
 net/mptcp/options.c | 6 +++++-
 3 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/net/mptcp/mib.c b/net/mptcp/mib.c
index 6a6f8151375a..0dac2863c6e1 100644
--- a/net/mptcp/mib.c
+++ b/net/mptcp/mib.c
@@ -57,6 +57,9 @@ static const struct snmp_mib mptcp_snmp_list[] = {
 	SNMP_MIB_ITEM("SubflowStale", MPTCP_MIB_SUBFLOWSTALE),
 	SNMP_MIB_ITEM("SubflowRecover", MPTCP_MIB_SUBFLOWRECOVER),
 	SNMP_MIB_ITEM("SndWndShared", MPTCP_MIB_SNDWNDSHARED),
+	SNMP_MIB_ITEM("RcvWndShared", MPTCP_MIB_RCVWNDSHARED),
+	SNMP_MIB_ITEM("RcvWndConflictUpdate", MPTCP_MIB_RCVWNDCONFLICTUPDATE),
+	SNMP_MIB_ITEM("RcvWndConflict", MPTCP_MIB_RCVWNDCONFLICT),
 	SNMP_MIB_SENTINEL
 };
 
diff --git a/net/mptcp/mib.h b/net/mptcp/mib.h
index 2411510bef66..2be3596374f4 100644
--- a/net/mptcp/mib.h
+++ b/net/mptcp/mib.h
@@ -50,6 +50,11 @@ enum linux_mptcp_mib_field {
 	MPTCP_MIB_SUBFLOWSTALE,		/* Subflows entered 'stale' status */
 	MPTCP_MIB_SUBFLOWRECOVER,	/* Subflows returned to active status after being stale */
 	MPTCP_MIB_SNDWNDSHARED,		/* Subflow snd wnd is overridden by msk's one */
+	MPTCP_MIB_RCVWNDSHARED,		/* Subflow rcv wnd is overridden by msk's one */
+	MPTCP_MIB_RCVWNDCONFLICTUPDATE,	/* subflow rcv wnd is overridden by msk's one due to
+					 * conflict with another subflow while updating msk rcv wnd
+					 */
+	MPTCP_MIB_RCVWNDCONFLICT,	/* Conflict with while updating msk rcv wnd */
 	__MPTCP_MIB_MAX
 };
 
diff --git a/net/mptcp/options.c b/net/mptcp/options.c
index 9c76a171af1e..559ff6ca6e66 100644
--- a/net/mptcp/options.c
+++ b/net/mptcp/options.c
@@ -1248,8 +1248,11 @@ static void mptcp_set_rwin(struct tcp_sock *tp, struct tcphdr *th)
 
 			if (rcv_wnd == rcv_wnd_old)
 				break;
-			if (before64(rcv_wnd_new, rcv_wnd))
+			if (before64(rcv_wnd_new, rcv_wnd)) {
+				MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_RCVWNDCONFLICTUPDATE);
 				goto raise_win;
+			}
+			MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_RCVWNDCONFLICT);
 			rcv_wnd_old = rcv_wnd;
 		};
 		return;
@@ -1275,6 +1278,7 @@ static void mptcp_set_rwin(struct tcp_sock *tp, struct tcphdr *th)
 		/* RFC1323 scaling applied */
 		new_win >>= tp->rx_opt.rcv_wscale;
 		th->window = htons(new_win);
+		MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_RCVWNDSHARED);
 	}
 }
 
-- 
2.35.1