[PATCH 34/75] isicom: redo locking to use tty port locks

Alan Cox
2009-01-02T13:46:13Z

From: Alan Cox <alan@redhat.com>

This helps set the basis for moving block_til_ready into common code. We also
introduce a tty_port_hangup helper as this will also be generally needed.

Signed-off-by: Alan Cox <alan@redhat.com>
---

drivers/char/isicom.c | 35 +++++++++++++++--------------------
drivers/char/synclinkmp.c | 20 ++++++++++++++------
drivers/char/tty_port.c | 24 ++++++++++++++++++++++++
include/linux/tty.h | 1 +
4 files changed, 54 insertions(+), 26 deletions(-)

diff --git a/drivers/char/isicom.c b/drivers/char/isicom.c
index a449449..db53db9 100644
--- a/drivers/char/isicom.c
+++ b/drivers/char/isicom.c
@@ -841,7 +841,6 @@ static int isicom_carrier_raised(struct tty_port *port)
static int block_til_ready(struct tty_struct *tty, struct file *filp,
struct isi_port *ip)
{
- struct isi_board *card = ip->card;
struct tty_port *port = &ip->port;
int do_clocal = 0, retval;
unsigned long flags;
@@ -876,11 +875,11 @@ static int block_til_ready(struct tty_struct *tty, struct file *filp,
retval = 0;
add_wait_queue(&port->open_wait, &wait);

- spin_lock_irqsave(&card->card_lock, flags);
+ spin_lock_irqsave(&port->lock, flags);
if (!tty_hung_up_p(filp))
port->count--;
port->blocked_open++;
- spin_unlock_irqrestore(&card->card_lock, flags);
+ spin_unlock_irqrestore(&port->lock, flags);

while (1) {
tty_port_raise_dtr_rts(port);
@@ -905,14 +904,13 @@ static int block_til_ready(struct tty_struct *tty, struct file *filp,
}
set_current_state(TASK_RUNNING);
remove_wait_queue(&port->open_wait, &wait);
- spin_lock_irqsave(&card->card_lock, flags);
+ spin_lock_irqsave(&port->lock, flags);
if (!tty_hung_up_p(filp))
port->count++;
port->blocked_open--;
- spin_unlock_irqrestore(&card->card_lock, flags);
- if (retval)
- return retval;
- port->flags |= ASYNC_NORMAL_ACTIVE;
+ if (retval == 0)
+ port->flags |= ASYNC_NORMAL_ACTIVE;
+ spin_unlock_irqrestore(&port->lock, flags);
return 0;
}

@@ -1034,9 +1032,9 @@ static void isicom_close(struct tty_struct *tty, struct file *filp)

pr_dbg("Close start!!!.\n");

- spin_lock_irqsave(&card->card_lock, flags);
+ spin_lock_irqsave(&port->port.lock, flags);
if (tty_hung_up_p(filp)) {
- spin_unlock_irqrestore(&card->card_lock, flags);
+ spin_unlock_irqrestore(&port->port.lock, flags);
return;
}

@@ -1054,12 +1052,12 @@ static void isicom_close(struct tty_struct *tty, struct file *filp)
}

if (port->port.count) {
- spin_unlock_irqrestore(&card->card_lock, flags);
+ spin_unlock_irqrestore(&port->port.lock, flags);
return;
}
port->port.flags |= ASYNC_CLOSING;
tty->closing = 1;
- spin_unlock_irqrestore(&card->card_lock, flags);
+ spin_unlock_irqrestore(&port->port.lock, flags);

if (port->port.closing_wait != ASYNC_CLOSING_WAIT_NONE)
tty_wait_until_sent(tty, port->port.closing_wait);
@@ -1076,22 +1074,22 @@ static void isicom_close(struct tty_struct *tty, struct file *filp)
isicom_flush_buffer(tty);
tty_ldisc_flush(tty);

- spin_lock_irqsave(&card->card_lock, flags);
+ spin_lock_irqsave(&port->port.lock, flags);
tty->closing = 0;

if (port->port.blocked_open) {
- spin_unlock_irqrestore(&card->card_lock, flags);
+ spin_unlock_irqrestore(&port->port.lock, flags);
if (port->port.close_delay) {
pr_dbg("scheduling until time out.\n");
msleep_interruptible(
jiffies_to_msecs(port->port.close_delay));
}
- spin_lock_irqsave(&card->card_lock, flags);
+ spin_lock_irqsave(&port->port.lock, flags);
wake_up_interruptible(&port->port.open_wait);
}
port->port.flags &= ~(ASYNC_NORMAL_ACTIVE | ASYNC_CLOSING);
wake_up_interruptible(&port->port.close_wait);
- spin_unlock_irqrestore(&card->card_lock, flags);
+ spin_unlock_irqrestore(&port->port.lock, flags);
}

/* write et all */
@@ -1430,10 +1428,7 @@ static void isicom_hangup(struct tty_struct *tty)
isicom_shutdown_port(port);
spin_unlock_irqrestore(&port->card->card_lock, flags);

- port->port.count = 0;
- port->port.flags &= ~ASYNC_NORMAL_ACTIVE;
- tty_port_tty_set(&port->port, NULL);
- wake_up_interruptible(&port->port.open_wait);
+ tty_port_hangup(&port->port);
}

diff --git a/drivers/char/synclinkmp.c b/drivers/char/synclinkmp.c
index fcf1ec7..1f5c21e 100644
--- a/drivers/char/synclinkmp.c
+++ b/drivers/char/synclinkmp.c
@@ -3331,6 +3331,17 @@ static int carrier_raised(struct tty_port *port)
return (info->serial_signals & SerialSignal_DCD) ? 1 : 0;
}

+static void raise_dtr_rts(struct tty_port *port)
+{
+ SLMP_INFO *info = container_of(port, SLMP_INFO, port);
+ unsigned long flags;
+
+ spin_lock_irqsave(&info->lock,flags);
+ info->serial_signals |= SerialSignal_RTS + SerialSignal_DTR;
+ set_signals(info);
+ spin_unlock_irqrestore(&info->lock,flags);
+}
+
/* Block the current process until the specified port is ready to open.
*/
static int block_til_ready(struct tty_struct *tty, struct file *filp,
@@ -3381,12 +3392,8 @@ static int block_til_ready(struct tty_struct *tty, struct file *filp,
port->blocked_open++;

while (1) {
- if ((tty->termios->c_cflag & CBAUD)) {
- spin_lock_irqsave(&info->lock,flags);
- info->serial_signals |= SerialSignal_RTS + SerialSignal_DTR;
- set_signals(info);
- spin_unlock_irqrestore(&info->lock,flags);
- }
+ if (tty->termios->c_cflag & CBAUD)
+ tty_port_raise_dtr_rts(port);

set_current_state(TASK_INTERRUPTIBLE);

@@ -3793,6 +3800,7 @@ static void add_device(SLMP_INFO *info)

static const struct tty_port_operations port_ops = {
.carrier_raised = carrier_raised,
+ .raise_dtr_rts = raise_dtr_rts,
};

/* Allocate and initialize a device instance structure
diff --git a/drivers/char/tty_port.c b/drivers/char/tty_port.c
index 0557b63..9f418bc 100644
--- a/drivers/char/tty_port.c
+++ b/drivers/char/tty_port.c
@@ -7,6 +7,7 @@
#include <linux/tty.h>
#include <linux/tty_driver.h>
#include <linux/tty_flip.h>
+#include <linux/serial.h>
#include <linux/timer.h>
#include <linux/string.h>
#include <linux/slab.h>
@@ -96,6 +97,29 @@ void tty_port_tty_set(struct tty_port *port, struct tty_struct *tty)
EXPORT_SYMBOL(tty_port_tty_set);

/**
+ * tty_port_hangup - hangup helper
+ * @port: tty port
+ *
+ * Perform port level tty hangup flag and count changes. Drop the tty
+ * reference.
+ */
+
+void tty_port_hangup(struct tty_port *port)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&port->lock, flags);
+ port->count = 0;
+ port->flags &= ~ASYNC_NORMAL_ACTIVE;
+ if (port->tty)
+ tty_kref_put(port->tty);
+ port->tty = NULL;
+ spin_unlock_irqrestore(&port->lock, flags);
+ wake_up_interruptible(&port->open_wait);
+}
+EXPORT_SYMBOL(tty_port_hangup);
+
+/**
* tty_port_carrier_raised - carrier raised check
* @port: tty port
*
diff --git a/include/linux/tty.h b/include/linux/tty.h
index 5001bbc..a1a9314 100644
--- a/include/linux/tty.h
+++ b/include/linux/tty.h
@@ -438,6 +438,7 @@ extern struct tty_struct *tty_port_tty_get(struct tty_port *port);
extern void tty_port_tty_set(struct tty_port *port, struct tty_struct *tty);
extern int tty_port_carrier_raised(struct tty_port *port);
extern void tty_port_raise_dtr_rts(struct tty_port *port);
+extern void tty_port_hangup(struct tty_port *port);

extern int tty_register_ldisc(int disc, struct tty_ldisc_ops *new_ldisc);
extern int tty_unregister_ldisc(int disc);