TTY: isdn/gigaset, use tty_port

Let us port the code to use tty_port. We now use open_count and tty
from there. This allows us also to use tty_port_tty_set with tty
refcounting instead of hand-written locking and logic.

Note that tty and open_count are no longer protected by cs->lock. It is
protected by tty_port->lock. But since all the places where they were
used are now switched to the helpers, we are fine.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Hansjoerg Lipp <hjlipp@web.de>
Acked-by: Tilman Schmidt <tilman@imap.cc>
Cc: <gigaset307x-common@lists.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

3 files changed, 21 insertions, 31 deletions

diff --git a/drivers/isdn/gigaset/common.c b/drivers/isdn/gigaset/common.c
index ac0186e54bf4..880f6ef0e18d 100644
--- a/drivers/isdn/gigaset/common.c
+++ b/drivers/isdn/gigaset/common.c
@@ -720,12 +720,11 @@ struct cardstate *gigaset_initcs(struct gigaset_driver *drv, int channels,
 
         tasklet_init(&cs->event_tasklet, gigaset_handle_event,
                      (unsigned long) cs);
+        tty_port_init(&cs->port);
         cs->commands_pending = 0;
         cs->cur_at_seq = 0;
         cs->gotfwver = -1;
-        cs->open_count = 0;
         cs->dev = NULL;
-        cs->tty = NULL;
         cs->tty_dev = NULL;
         cs->cidmode = cidmode != 0;
         cs->tabnocid = gigaset_tab_nocid;
diff --git a/drivers/isdn/gigaset/gigaset.h b/drivers/isdn/gigaset/gigaset.h
index 212efaf9a4e4..f877726d664b 100644
--- a/drivers/isdn/gigaset/gigaset.h
+++ b/drivers/isdn/gigaset/gigaset.h
@@ -433,8 +433,7 @@ struct cardstate {
         spinlock_t cmdlock;
         unsigned curlen, cmdbytes;
 
-        unsigned open_count;
-        struct tty_struct *tty;
+        struct tty_port port;
         struct tasklet_struct if_wake_tasklet;
         unsigned control_state;
 
diff --git a/drivers/isdn/gigaset/interface.c b/drivers/isdn/gigaset/interface.c
index 8ff50b056285..8f8814afce86 100644
--- a/drivers/isdn/gigaset/interface.c
+++ b/drivers/isdn/gigaset/interface.c
@@ -146,7 +146,6 @@ static const struct tty_operations if_ops = {
 static int if_open(struct tty_struct *tty, struct file *filp)
 {
         struct cardstate *cs;
-        unsigned long flags;
 
         gig_dbg(DEBUG_IF, "%d+%d: %s()",
                 tty->driver->minor_start, tty->index, __func__);
@@ -161,12 +160,10 @@ static int if_open(struct tty_struct *tty, struct file *filp)
         }
         tty->driver_data = cs;
 
-        ++cs->open_count;
+        ++cs->port.count;
 
-        if (cs->open_count == 1) {
-                spin_lock_irqsave(&cs->lock, flags);
-                cs->tty = tty;
-                spin_unlock_irqrestore(&cs->lock, flags);
+        if (cs->port.count == 1) {
+                tty_port_tty_set(&cs->port, tty);
                 tty->low_latency = 1;
         }
 
@@ -177,7 +174,6 @@ static int if_open(struct tty_struct *tty, struct file *filp)
 static void if_close(struct tty_struct *tty, struct file *filp)
 {
         struct cardstate *cs = tty->driver_data;
-        unsigned long flags;
 
         if (!cs) { /* happens if we didn't find cs in open */
                 printk(KERN_DEBUG "%s: no cardstate\n", __func__);
@@ -190,15 +186,10 @@ static void if_close(struct tty_struct *tty, struct file *filp)
 
         if (!cs->connected)
                 gig_dbg(DEBUG_IF, "not connected");     /* nothing to do */
-        else if (!cs->open_count)
+        else if (!cs->port.count)
                 dev_warn(cs->dev, "%s: device not opened\n", __func__);
-        else {
-                if (!--cs->open_count) {
-                        spin_lock_irqsave(&cs->lock, flags);
-                        cs->tty = NULL;
-                        spin_unlock_irqrestore(&cs->lock, flags);
-                }
-        }
+        else if (!--cs->port.count)
+                tty_port_tty_set(&cs->port, NULL);
 
         mutex_unlock(&cs->mutex);
 
@@ -511,10 +502,13 @@ out:
 /* wakeup tasklet for the write operation */
 static void if_wake(unsigned long data)
 {
-        struct cardstate *cs = (struct cardstate *) data;
+        struct cardstate *cs = (struct cardstate *)data;
+        struct tty_struct *tty = tty_port_tty_get(&cs->port);
 
-        if (cs->tty)
-                tty_wakeup(cs->tty);
+        if (tty) {
+                tty_wakeup(tty);
+                tty_kref_put(tty);
+        }
 }
 
 /*** interface to common ***/
@@ -567,18 +561,16 @@ void gigaset_if_free(struct cardstate *cs)
 void gigaset_if_receive(struct cardstate *cs,
                         unsigned char *buffer, size_t len)
 {
-        unsigned long flags;
-        struct tty_struct *tty;
+        struct tty_struct *tty = tty_port_tty_get(&cs->port);
 
-        spin_lock_irqsave(&cs->lock, flags);
-        tty = cs->tty;
-        if (tty == NULL)
+        if (tty == NULL) {
                 gig_dbg(DEBUG_IF, "receive on closed device");
-        else {
-                tty_insert_flip_string(tty, buffer, len);
-                tty_flip_buffer_push(tty);
+                return;
         }
-        spin_unlock_irqrestore(&cs->lock, flags);
+
+        tty_insert_flip_string(tty, buffer, len);
+        tty_flip_buffer_push(tty);
+        tty_kref_put(tty);
 }
 EXPORT_SYMBOL_GPL(gigaset_if_receive);