tty: kref nozomi

Update the nozomi driver to use krefs

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 45 insertions, 40 deletions

diff --git a/drivers/char/nozomi.c b/drivers/char/nozomi.c
index 9a34a1935283..d6102b644b55 100644
--- a/drivers/char/nozomi.c
+++ b/drivers/char/nozomi.c
@@ -353,6 +353,7 @@ struct ctrl_ul {
 
 /* This holds all information that is needed regarding a port */
 struct port {
+        struct tty_port port;
         u8 update_flow_control;
         struct ctrl_ul ctrl_ul;
         struct ctrl_dl ctrl_dl;
@@ -365,8 +366,6 @@ struct port {
         u8 toggle_ul;
         u16 token_dl;
 
-        struct tty_struct *tty;
-        int tty_open_count;
         /* mutex to ensure one access patch to this port */
         struct mutex tty_sem;
         wait_queue_head_t tty_wait;
@@ -788,14 +787,14 @@ static void disable_transmit_dl(enum port_type port, struct nozomi *dc)
  * Return 1 - send buffer to card and ack.
  * Return 0 - don't ack, don't send buffer to card.
  */
-static int send_data(enum port_type index, const struct nozomi *dc)
+static int send_data(enum port_type index, struct nozomi *dc)
 {
         u32 size = 0;
-        const struct port *port = &dc->port[index];
+        struct port *port = &dc->port[index];
         const u8 toggle = port->toggle_ul;
         void __iomem *addr = port->ul_addr[toggle];
         const u32 ul_size = port->ul_size[toggle];
-        struct tty_struct *tty = port->tty;
+        struct tty_struct *tty = tty_port_tty_get(&port->port);
 
         /* Get data from tty and place in buf for now */
         size = __kfifo_get(port->fifo_ul, dc->send_buf,
@@ -803,6 +802,7 @@ static int send_data(enum port_type index, const struct nozomi *dc)
 
         if (size == 0) {
                 DBG4("No more data to send, disable link:");
+                tty_kref_put(tty);
                 return 0;
         }
 
@@ -815,6 +815,7 @@ static int send_data(enum port_type index, const struct nozomi *dc)
         if (tty)
                 tty_wakeup(tty);
 
+        tty_kref_put(tty);
         return 1;
 }
 
@@ -826,7 +827,7 @@ static int receive_data(enum port_type index, struct nozomi *dc)
         u32 offset = 4;
         struct port *port = &dc->port[index];
         void __iomem *addr = port->dl_addr[port->toggle_dl];
-        struct tty_struct *tty = port->tty;
+        struct tty_struct *tty = tty_port_tty_get(&port->port);
         int i;
 
         if (unlikely(!tty)) {
@@ -870,7 +871,7 @@ static int receive_data(enum port_type index, struct nozomi *dc)
         }
 
         set_bit(index, &dc->flip);
-
+        tty_kref_put(tty);
         return 1;
 }
 
@@ -1276,9 +1277,15 @@ static irqreturn_t interrupt_handler(int irq, void *dev_id)
 
 exit_handler:
         spin_unlock(&dc->spin_mutex);
-        for (a = 0; a < NOZOMI_MAX_PORTS; a++)
-                if (test_and_clear_bit(a, &dc->flip))
-                        tty_flip_buffer_push(dc->port[a].tty);
+        for (a = 0; a < NOZOMI_MAX_PORTS; a++) {
+                struct tty_struct *tty;
+                if (test_and_clear_bit(a, &dc->flip)) {
+                        tty = tty_port_tty_get(&dc->port[a].port);
+                        if (tty)
+                                tty_flip_buffer_push(tty);
+                        tty_kref_put(tty);
+                }
+        }
         return IRQ_HANDLED;
 none:
         spin_unlock(&dc->spin_mutex);
@@ -1453,12 +1460,10 @@ static int __devinit nozomi_card_init(struct pci_dev *pdev,
 
         for (i = 0; i < MAX_PORT; i++) {
                 mutex_init(&dc->port[i].tty_sem);
-                dc->port[i].tty_open_count = 0;
-                dc->port[i].tty = NULL;
+                tty_port_init(&dc->port[i].port);
                 tty_register_device(ntty_driver, dc->index_start + i,
                                                         &pdev->dev);
         }
-
         return 0;
 
 err_free_sbuf:
@@ -1482,14 +1487,16 @@ static void __devexit tty_exit(struct nozomi *dc)
 
         flush_scheduled_work();
 
-        for (i = 0; i < MAX_PORT; ++i)
-                if (dc->port[i].tty && \
-                                list_empty(&dc->port[i].tty->hangup_work.entry))
-                        tty_hangup(dc->port[i].tty);
-
+        for (i = 0; i < MAX_PORT; ++i) {
+                struct tty_struct *tty = tty_port_tty_get(&dc->port[i].port);
+                if (tty && list_empty(&tty->hangup_work.entry))
+                        tty_hangup(tty);
+                tty_kref_put(tty);
+        }
+        /* Racy below - surely should wait for scheduled work to be done or
+           complete off a hangup method ? */
         while (dc->open_ttys)
                 msleep(1);
-
         for (i = dc->index_start; i < dc->index_start + MAX_PORT; ++i)
                 tty_unregister_device(ntty_driver, i);
 }
@@ -1579,23 +1586,22 @@ static int ntty_open(struct tty_struct *tty, struct file *file)
         if (mutex_lock_interruptible(&port->tty_sem))
                 return -ERESTARTSYS;
 
-        port->tty_open_count++;
+        port->port.count++;
         dc->open_ttys++;
 
         /* Enable interrupt downlink for channel */
-        if (port->tty_open_count == 1) {
+        if (port->port.count == 1) {
+                /* FIXME: is this needed now ? */
                 tty->low_latency = 1;
                 tty->driver_data = port;
-                port->tty = tty;
+                tty_port_tty_set(&port->port, tty);
                 DBG1("open: %d", port->token_dl);
                 spin_lock_irqsave(&dc->spin_mutex, flags);
                 dc->last_ier = dc->last_ier | port->token_dl;
                 writew(dc->last_ier, dc->reg_ier);
                 spin_unlock_irqrestore(&dc->spin_mutex, flags);
         }
-
         mutex_unlock(&port->tty_sem);
-
         return 0;
 }
 
@@ -1606,31 +1612,30 @@ static int ntty_open(struct tty_struct *tty, struct file *file)
 static void ntty_close(struct tty_struct *tty, struct file *file)
 {
         struct nozomi *dc = get_dc_by_tty(tty);
-        struct port *port = tty->driver_data;
+        struct port *nport = tty->driver_data;
+        struct tty_port *port = &nport->port;
         unsigned long flags;
 
-        if (!dc || !port)
+        if (!dc || !nport)
                 return;
 
-        if (mutex_lock_interruptible(&port->tty_sem))
-                return;
+        /* Users cannot interrupt a close */
+        mutex_lock(&nport->tty_sem);
 
-        if (!port->tty_open_count)
-                goto exit;
+        WARN_ON(!port->count);
 
         dc->open_ttys--;
-        port->tty_open_count--;
+        port->count--;
+        tty_port_tty_set(port, NULL);
 
-        if (port->tty_open_count == 0) {
-                DBG1("close: %d", port->token_dl);
+        if (port->count == 0) {
+                DBG1("close: %d", nport->token_dl);
                 spin_lock_irqsave(&dc->spin_mutex, flags);
-                dc->last_ier &= ~(port->token_dl);
+                dc->last_ier &= ~(nport->token_dl);
                 writew(dc->last_ier, dc->reg_ier);
                 spin_unlock_irqrestore(&dc->spin_mutex, flags);
         }
-
-exit:
-        mutex_unlock(&port->tty_sem);
+        mutex_unlock(&nport->tty_sem);
 }
 
 /*
@@ -1660,7 +1665,7 @@ static int ntty_write(struct tty_struct *tty, const unsigned char *buffer,
                 return -EAGAIN;
         }
 
-        if (unlikely(!port->tty_open_count)) {
+        if (unlikely(!port->port.count)) {
                 DBG1(" ");
                 goto exit;
         }
@@ -1710,7 +1715,7 @@ static int ntty_write_room(struct tty_struct *tty)
         if (!mutex_trylock(&port->tty_sem))
                 return 0;
 
-        if (!port->tty_open_count)
+        if (!port->port.count)
                 goto exit;
 
         room = port->fifo_ul->size - __kfifo_len(port->fifo_ul);
@@ -1866,7 +1871,7 @@ static s32 ntty_chars_in_buffer(struct tty_struct *tty)
                 goto exit_in_buffer;
         }
 
-        if (unlikely(!port->tty_open_count)) {
+        if (unlikely(!port->port.count)) {
                 dev_err(&dc->pdev->dev, "No tty open?\n");
                 rval = -ENODEV;
                 goto exit_in_buffer;