[PATCH 50/75] tty: kref nozomi

Alan Cox
2009-01-02T13:47:20Z

From: Alan Cox <alan@redhat.com>

Update the nozomi driver to use krefs
---

drivers/char/nozomi.c | 85 ++++++++++++++++++++++++++-----------------------
1 files changed, 45 insertions(+), 40 deletions(-)

diff --git a/drivers/char/nozomi.c b/drivers/char/nozomi.c
index 9a34a19..d6102b6 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;