[PATCH]: Mux n_gsm: Add a DLCI hangup state and callback

["Gwenn Bourrée" <gwenn.bourree-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>]

Dear kernel tty maintainers,
 
Please review the following patch:

From 6e006bd522124d0e8a2f6075099a21f7051a426f Mon Sep 17 00:00:00 2001
From: Gwenn Bourree <gwenn.bourree@intel.com>
Date: Mon, 29 Jun 2015 17:26:01 +0200
Subject: [PATCH] Mux n_gsm: Add a DLCI hangup state and callback

Use of asynchronous hangup instead of vhangup.

Signed-off-by: Gwenn Bourree <gwenn.bourree@intel.com>
Signed-off-by: Gwenn Bourree <gwenn.bourree@intel.com>
Signed-off-by: Mustapha Ben Zoubeir <mustaphax.ben.zoubeir@intel.com>
Signed-off-by: Nicolas LOUIS <nicolasx.louis@intel.com>
Reviewed-by: Ravindran, Arun <arun.ravindran@intel.com

---
 drivers/tty/n_gsm.c | 27 +++++++++++++++++++++++++--
 1 file changed, 25 insertions(+), 2 deletions(-)

diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c
index d6e0ea0..762f555 100644
--- a/drivers/tty/n_gsm.c
+++ b/drivers/tty/n_gsm.c
@@ -135,6 +135,7 @@ struct gsm_dlci {
 #define DLCI_OPENING		1	/* Sending SABM not seen UA */
 #define DLCI_OPEN		2	/* SABM/UA complete */
 #define DLCI_CLOSING		3	/* Sending DISC not seen UA/DM */
+#define DLCI_HANGUP		4	/*HANGUP received  */
 	struct mutex mutex;
 
 	/* Link layer */
@@ -1530,7 +1531,8 @@ static void gsm_dlci_begin_open(struct gsm_dlci
*dlci)
 static void gsm_dlci_begin_close(struct gsm_dlci *dlci)
 {
 	struct gsm_mux *gsm = dlci->gsm;
-	if (dlci->state == DLCI_CLOSED || dlci->state == DLCI_CLOSING)
+	if (dlci->state == DLCI_CLOSED || dlci->state == DLCI_CLOSING ||
+		dlci->state == DLCI_HANGUP)
 		return;
 	dlci->retries = gsm->n2;
 	dlci->state = DLCI_CLOSING;
@@ -1717,7 +1719,7 @@ static void gsm_dlci_release(struct gsm_dlci
*dlci)
 		gsm_destroy_network(dlci);
 		mutex_unlock(&dlci->mutex);
 
-		tty_vhangup(tty);
+		tty_hangup(tty);
 
 		tty_port_tty_set(&dlci->port, NULL);
 		tty_kref_put(tty);
@@ -2339,6 +2341,26 @@ static void gsmld_flush_buffer(struct tty_struct
*tty)
 }
 
 /**
+ *	gsmld_hangup		-	hangup the ldisc for this tty
+ *	@tty: device
+ */
+
+static int gsmld_hangup(struct tty_struct *tty)
+{
+	struct gsm_mux *gsm = tty->disc_data;
+	int i;
+	struct gsm_dlci *dlci;
+
+	for (i = NUM_DLCI-1; i >= 0; i--) {
+		dlci = gsm->dlci[i];
+		if (dlci)
+			dlci->state = DLCI_HANGUP;
+	}
+
+	return 0;
+}
+
+/**
  *	gsmld_close		-	close the ldisc for this tty
  *	@tty: device
  *
@@ -2836,6 +2858,7 @@ static struct tty_ldisc_ops tty_ldisc_packet = {
 	.name            = "n_gsm",
 	.open            = gsmld_open,
 	.close           = gsmld_close,
+	.hangup          = gsmld_hangup,
 	.flush_buffer    = gsmld_flush_buffer,
 	.chars_in_buffer = gsmld_chars_in_buffer,
 	.read            = gsmld_read,


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