[PATCH 60/76] pty: Coding style and polish

Alan Cox
2008-10-05T16:26:43Z

We've done the heavy lifting now its time to mop up a bit

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

drivers/char/pty.c | 86 +++++++++++++++++++++++++++-------------------------
1 files changed, 44 insertions(+), 42 deletions(-)

diff --git a/drivers/char/pty.c b/drivers/char/pty.c
index a391bad..c3ab8c3 100644
--- a/drivers/char/pty.c
+++ b/drivers/char/pty.c
@@ -8,10 +8,12 @@
* Added TTY_DO_WRITE_WAKEUP to enable n_tty to send POLL_OUT to
* waiting writers -- Sapan Bhatia <sapan@corewars.org>
*
- *
+ * When reading this code see also fs/devpts. In particular note that the
+ * driver_data field is used by the devpts side as a binding to the devpts
+ * inode.
*/

-#include <linux/module.h> /* For EXPORT_SYMBOL */
+#include <linux/module.h>

#include <linux/errno.h>
#include <linux/interrupt.h>
@@ -24,26 +26,24 @@
#include <linux/init.h>
#include <linux/sysctl.h>
#include <linux/device.h>
-
-#include <asm/uaccess.h>
-#include <asm/system.h>
+#include <linux/uaccess.h>
#include <linux/bitops.h>
#include <linux/devpts_fs.h>

+#include <asm/system.h>
+
/* These are global because they are accessed in tty_io.c */
#ifdef CONFIG_UNIX98_PTYS
struct tty_driver *ptm_driver;
static struct tty_driver *pts_driver;
#endif

-static void pty_close(struct tty_struct * tty, struct file * filp)
+static void pty_close(struct tty_struct *tty, struct file *filp)
{
- if (!tty)
- return;
- if (tty->driver->subtype == PTY_TYPE_MASTER) {
- if (tty->count > 1)
- printk("master pty_close: count = %d!!\n", tty->count);
- } else {
+ BUG_ON(!tty);
+ if (tty->driver->subtype == PTY_TYPE_MASTER)
+ WARN_ON(tty->count > 1);
+ else {
if (tty->count > 2)
return;
}
@@ -70,13 +70,13 @@ static void pty_close(struct tty_struct * tty, struct file * filp)
* The unthrottle routine is called by the line discipline to signal
* that it can receive more characters. For PTY's, the TTY_THROTTLED
* flag is always set, to force the line discipline to always call the
- * unthrottle routine when there are fewer than TTY_THRESHOLD_UNTHROTTLE
+ * unthrottle routine when there are fewer than TTY_THRESHOLD_UNTHROTTLE
* characters in the queue. This is necessary since each time this
* happens, we need to wake up any sleeping processes that could be
* (1) trying to send data to the pty, or (2) waiting in wait_until_sent()
* for the pty buffer to be drained.
*/
-static void pty_unthrottle(struct tty_struct * tty)
+static void pty_unthrottle(struct tty_struct *tty)
{
struct tty_struct *o_tty = tty->link;

@@ -88,7 +88,7 @@ static void pty_unthrottle(struct tty_struct * tty)
}

/*
- * WSH 05/24/97: modified to
+ * WSH 05/24/97: modified to
* (1) use space in tty->flip instead of a shared temp buffer
* The flip buffers aren't being used for a pty, so there's lots
* of space available. The buffer is protected by a per-pty
@@ -101,7 +101,8 @@ static void pty_unthrottle(struct tty_struct * tty)
* not our partners. We can't just take the other one blindly without
* risking deadlocks.
*/
-static int pty_write(struct tty_struct * tty, const unsigned char *buf, int count)
+static int pty_write(struct tty_struct *tty, const unsigned char *buf,
+ int count)
{
struct tty_struct *to = tty->link;
int c;
@@ -113,7 +114,7 @@ static int pty_write(struct tty_struct * tty, const unsigned char *buf, int coun
if (c > count)
c = count;
to->ldisc.ops->receive_buf(to, buf, NULL, c);
-
+
return c;
}

@@ -129,17 +130,17 @@ static int pty_write_room(struct tty_struct *tty)

/*
* WSH 05/24/97: Modified for asymmetric MASTER/SLAVE behavior
- * The chars_in_buffer() value is used by the ldisc select() function
+ * The chars_in_buffer() value is used by the ldisc select() function
* to hold off writing when chars_in_buffer > WAKEUP_CHARS (== 256).
* The pty driver chars_in_buffer() Master/Slave must behave differently:
*
* The Master side needs to allow typed-ahead commands to accumulate
* while being canonicalized, so we report "our buffer" as empty until
* some threshold is reached, and then report the count. (Any count >
- * WAKEUP_CHARS is regarded by select() as "full".) To avoid deadlock
- * the count returned must be 0 if no canonical data is available to be
+ * WAKEUP_CHARS is regarded by select() as "full".) To avoid deadlock
+ * the count returned must be 0 if no canonical data is available to be
* read. (The N_TTY ldisc.chars_in_buffer now knows this.)
- *
+ *
* The Slave side passes all characters in raw mode to the Master side's
* buffer where they can be read immediately, so in this case we can
* return the true count in the buffer.
@@ -156,21 +157,22 @@ static int pty_chars_in_buffer(struct tty_struct *tty)
/* The ldisc must report 0 if no characters available to be read */
count = to->ldisc.ops->chars_in_buffer(to);

- if (tty->driver->subtype == PTY_TYPE_SLAVE) return count;
+ if (tty->driver->subtype == PTY_TYPE_SLAVE)
+ return count;

- /* Master side driver ... if the other side's read buffer is less than
+ /* Master side driver ... if the other side's read buffer is less than
* half full, return 0 to allow writers to proceed; otherwise return
- * the count. This leaves a comfortable margin to avoid overflow,
+ * the count. This leaves a comfortable margin to avoid overflow,
* and still allows half a buffer's worth of typed-ahead commands.
*/
- return ((count < N_TTY_BUF_SIZE/2) ? 0 : count);
+ return (count < N_TTY_BUF_SIZE/2) ? 0 : count;
}

/* Set the lock flag on a pty */
-static int pty_set_lock(struct tty_struct *tty, int __user * arg)
+static int pty_set_lock(struct tty_struct *tty, int __user *arg)
{
int val;
- if (get_user(val,arg))
+ if (get_user(val, arg))
return -EFAULT;
if (val)
set_bit(TTY_PTY_LOCK, &tty->flags);
@@ -183,13 +185,13 @@ static void pty_flush_buffer(struct tty_struct *tty)
{
struct tty_struct *to = tty->link;
unsigned long flags;
-
+
if (!to)
return;
-
+
if (to->ldisc.ops->flush_buffer)
to->ldisc.ops->flush_buffer(to);
-
+
if (to->packet) {
spin_lock_irqsave(&tty->ctrl_lock, flags);
tty->ctrl_status |= TIOCPKT_FLUSHWRITE;
@@ -198,7 +200,7 @@ static void pty_flush_buffer(struct tty_struct *tty)
}
}

-static int pty_open(struct tty_struct *tty, struct file * filp)
+static int pty_open(struct tty_struct *tty, struct file *filp)
{
int retval = -ENODEV;

@@ -221,10 +223,11 @@ out:
return retval;
}

-static void pty_set_termios(struct tty_struct *tty, struct ktermios *old_termios)
+static void pty_set_termios(struct tty_struct *tty,
+ struct ktermios *old_termios)
{
- tty->termios->c_cflag &= ~(CSIZE | PARENB);
- tty->termios->c_cflag |= (CS8 | CREAD);
+ tty->termios->c_cflag &= ~(CSIZE | PARENB);
+ tty->termios->c_cflag |= (CS8 | CREAD);
}

static int pty_install(struct tty_driver *driver, struct tty_struct *tty)
@@ -254,7 +257,7 @@ static int pty_install(struct tty_driver *driver, struct tty_struct *tty)
tty_free_termios(tty);
goto free_mem_out;
}
-
+
/*
* Everything allocated ... set up the o_tty structure.
*/
@@ -381,9 +384,9 @@ static inline void legacy_pty_init(void) { }
* Otherwise one can eat up all kernel memory by opening /dev/ptmx repeatedly.
*/
int pty_limit = NR_UNIX98_PTY_DEFAULT;
-static int pty_limit_min = 0;
+static int pty_limit_min;
static int pty_limit_max = NR_UNIX98_PTY_MAX;
-static int pty_count = 0;
+static int pty_count;

static struct cdev ptmx_cdev;

@@ -537,11 +540,10 @@ static int pty_unix98_install(struct tty_driver *driver, struct tty_struct *tty)
pty_count++;
return 0;
free_mem_out:
- kfree(o_tty->termios);
+ pty_unix98_shutdown(o_tty);
module_put(o_tty->driver->owner);
free_tty_struct(o_tty);
- kfree(tty->termios_locked);
- kfree(tty->termios);
+ pty_unix98_shutdown(tty);
free_tty_struct(tty);
module_put(driver->owner);
return -ENOMEM;
@@ -691,13 +693,13 @@ static void __init unix98_pty_init(void)
TTY_DRIVER_DYNAMIC_DEV | TTY_DRIVER_DEVPTS_MEM;
pts_driver->other = ptm_driver;
tty_set_operations(pts_driver, &pty_unix98_ops);
-
+
if (tty_register_driver(ptm_driver))
panic("Couldn't register Unix98 ptm driver");
if (tty_register_driver(pts_driver))
panic("Couldn't register Unix98 pts driver");

- register_sysctl_table(pty_root_table);
+ register_sysctl_table(pty_root_table);

/* Now create the /dev/ptmx special device */
tty_default_fops(&ptmx_fops);