[PATCH 5/9] tty: n_gsm: add open_error counter to gsm_mux

["D. Starke" <daniel.starke@xxxxxxxxxxx>]

From: Daniel Starke <daniel.starke@xxxxxxxxxxx>

Extend the n_gsm link statistics by a failed link open counter in
preparation for an upcoming patch which will expose these.
This counter is increased whenever an attempt to open the control channel
failed.

Signed-off-by: Daniel Starke <daniel.starke@xxxxxxxxxxx>
---
 drivers/tty/n_gsm.c | 33 ++++++++++++++++++++++++++-------
 1 file changed, 26 insertions(+), 7 deletions(-)

diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c
index d42b92cbae88..9f6669686c59 100644
--- a/drivers/tty/n_gsm.c
+++ b/drivers/tty/n_gsm.c
@@ -338,6 +338,7 @@ struct gsm_mux {
 	unsigned long bad_fcs;
 	unsigned long malformed;
 	unsigned long io_error;
+	unsigned long open_error;
 	unsigned long bad_size;
 	unsigned long unsupported;
 };
@@ -1729,25 +1730,32 @@ static void gsm_control_negotiation(struct gsm_mux *gsm, unsigned int cr,
 	struct gsm_dlci *dlci;
 	struct gsm_dlci_param_bits *params;
 
-	if (dlen < sizeof(struct gsm_dlci_param_bits))
+	if (dlen < sizeof(struct gsm_dlci_param_bits)) {
+		gsm->open_error++;
 		return;
+	}
 
 	/* Invalid DLCI? */
 	params = (struct gsm_dlci_param_bits *)data;
 	addr = FIELD_GET(PN_D_FIELD_DLCI, params->d_bits);
-	if (addr == 0 || addr >= NUM_DLCI || !gsm->dlci[addr])
+	if (addr == 0 || addr >= NUM_DLCI || !gsm->dlci[addr]) {
+		gsm->open_error++;
 		return;
+	}
 	dlci = gsm->dlci[addr];
 
 	/* Too late for parameter negotiation? */
-	if ((!cr && dlci->state == DLCI_OPENING) || dlci->state == DLCI_OPEN)
+	if ((!cr && dlci->state == DLCI_OPENING) || dlci->state == DLCI_OPEN) {
+		gsm->open_error++;
 		return;
+	}
 
 	/* Process the received parameters */
 	if (gsm_process_negotiation(gsm, addr, cr, params) != 0) {
 		/* Negotiation failed. Close the link. */
 		if (debug & DBG_ERRORS)
 			pr_info("%s PN failed\n", __func__);
+		gsm->open_error++;
 		gsm_dlci_close(dlci);
 		return;
 	}
@@ -1767,6 +1775,7 @@ static void gsm_control_negotiation(struct gsm_mux *gsm, unsigned int cr,
 	} else {
 		if (debug & DBG_ERRORS)
 			pr_info("%s PN in invalid state\n", __func__);
+		gsm->open_error++;
 	}
 }
 
@@ -2220,6 +2229,7 @@ static void gsm_dlci_t1(struct timer_list *t)
 			dlci->retries--;
 			mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
 		} else {
+			gsm->open_error++;
 			gsm_dlci_begin_close(dlci); /* prevent half open link */
 		}
 		break;
@@ -2235,6 +2245,7 @@ static void gsm_dlci_t1(struct timer_list *t)
 			dlci->mode = DLCI_MODE_ADM;
 			gsm_dlci_open(dlci);
 		} else {
+			gsm->open_error++;
 			gsm_dlci_begin_close(dlci); /* prevent half open link */
 		}
 
@@ -2756,12 +2767,16 @@ static void gsm_queue(struct gsm_mux *gsm)
 
 	switch (gsm->control) {
 	case SABM|PF:
-		if (cr == 1)
+		if (cr == 1) {
+			gsm->open_error++;
 			goto invalid;
+		}
 		if (dlci == NULL)
 			dlci = gsm_dlci_alloc(gsm, address);
-		if (dlci == NULL)
+		if (dlci == NULL) {
+			gsm->open_error++;
 			return;
+		}
 		if (dlci->dead)
 			gsm_response(gsm, address, DM|PF);
 		else {
@@ -3754,8 +3769,10 @@ static int gsmld_ioctl(struct tty_struct *tty, unsigned int cmd,
 		dlci = gsm->dlci[dc.channel];
 		if (!dlci) {
 			dlci = gsm_dlci_alloc(gsm, dc.channel);
-			if (!dlci)
+			if (!dlci) {
+				gsm->open_error++;
 				return -ENOMEM;
+			}
 		}
 		gsm_dlci_copy_config_values(dlci, &dc);
 		if (copy_to_user((void __user *)arg, &dc, sizeof(dc)))
@@ -3769,8 +3786,10 @@ static int gsmld_ioctl(struct tty_struct *tty, unsigned int cmd,
 		dlci = gsm->dlci[dc.channel];
 		if (!dlci) {
 			dlci = gsm_dlci_alloc(gsm, dc.channel);
-			if (!dlci)
+			if (!dlci) {
+				gsm->open_error++;
 				return -ENOMEM;
+			}
 		}
 		return gsm_dlci_config(dlci, &dc, 0);
 	default:
-- 
2.34.1