TTY: n_gsm, use kref from tty_port

After commit "TTY: move tty buffers to tty_port", the tty buffers are
not freed in some drivers. This is because tty_port_destructor is not
called whenever a tty_port is freed. This was an assumption I counted
with but was unfortunately untrue. So fix the drivers to fulfil this
assumption.

Here it is enough to switch to refcounting in tty_port.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 5 insertions, 6 deletions

diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c
index 1e8e8ce55959..dcc0430a49c8 100644
--- a/drivers/tty/n_gsm.c
+++ b/drivers/tty/n_gsm.c
@@ -134,7 +134,6 @@ 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 */
-        struct kref ref;                /* freed from port or mux close */
         struct mutex mutex;
 
         /* Link layer */
@@ -1635,7 +1634,6 @@ static struct gsm_dlci *gsm_dlci_alloc(struct gsm_mux *gsm, int addr)
         if (dlci == NULL)
                 return NULL;
         spin_lock_init(&dlci->lock);
-        kref_init(&dlci->ref);
         mutex_init(&dlci->mutex);
         dlci->fifo = &dlci->_fifo;
         if (kfifo_alloc(&dlci->_fifo, 4096, GFP_KERNEL) < 0) {
@@ -1669,9 +1667,9 @@ static struct gsm_dlci *gsm_dlci_alloc(struct gsm_mux *gsm, int addr)
  *
  *      Can sleep.
  */
-static void gsm_dlci_free(struct kref *ref)
+static void gsm_dlci_free(struct tty_port *port)
 {
-        struct gsm_dlci *dlci = container_of(ref, struct gsm_dlci, ref);
+        struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
 
         del_timer_sync(&dlci->t1);
         dlci->gsm->dlci[dlci->addr] = NULL;
@@ -1683,12 +1681,12 @@ static void gsm_dlci_free(struct kref *ref)
 
 static inline void dlci_get(struct gsm_dlci *dlci)
 {
-        kref_get(&dlci->ref);
+        tty_port_get(&dlci->port);
 }
 
 static inline void dlci_put(struct gsm_dlci *dlci)
 {
-        kref_put(&dlci->ref, gsm_dlci_free);
+        tty_port_put(&dlci->port);
 }
 
 /**
@@ -2874,6 +2872,7 @@ static void gsm_dtr_rts(struct tty_port *port, int onoff)
 static const struct tty_port_operations gsm_port_ops = {
         .carrier_raised = gsm_carrier_raised,
         .dtr_rts = gsm_dtr_rts,
+        .destruct = gsm_dlci_free,
 };
 
 static int gsmtty_install(struct tty_driver *driver, struct tty_struct *tty)