[PATCH 7/9] tty: n_gsm: increase gsm_mux unsupported counted where appropriate

["D. Starke" <daniel.starke@siemens.com>]

From: Daniel Starke <daniel.starke@siemens.com>

The structure gsm_mux contains the 'unsupported' field. However, there is
currently no place in the code which increases this counter.

Increase the 'unsupported' statistics counter in the following case:
- an unsupported frame type has been requested by the peer via parameter
  negotiation
- a control frame with an unsupported but known command has been received

Signed-off-by: Daniel Starke <daniel.starke@siemens.com>
---
 drivers/tty/n_gsm.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c
index 317aa67ed169..49cb2dbfa233 100644
--- a/drivers/tty/n_gsm.c
+++ b/drivers/tty/n_gsm.c
@@ -1589,6 +1589,7 @@ static int gsm_process_negotiation(struct gsm_mux *gsm, unsigned int addr,
 		if (debug & DBG_ERRORS)
 			pr_info("%s unsupported I frame request in PN\n",
 				__func__);
+		gsm->unsupported++;
 		return -EINVAL;
 	default:
 		if (debug & DBG_ERRORS)
@@ -1896,6 +1897,8 @@ static void gsm_control_message(struct gsm_mux *gsm, unsigned int command,
 		/* Optional unsupported commands */
 	case CMD_RPN:	/* Remote port negotiation */
 	case CMD_SNC:	/* Service negotiation command */
+		gsm->unsupported++;
+		fallthrough;
 	default:
 		/* Reply to bad commands with an NSC */
 		buf[0] = command;
-- 
2.34.1