Piteball/android_kernel_samsung_msm8976
1
1
Fork 0
mirror of https://github.com/team-infusion-developers/android_kernel_samsung_msm8976.git synced 2024-11-01 10:33:27 +00:00
Code Issues Projects Releases Wiki Activity

pty: Coding style and polish

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

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Alan Cox 2008-10-13 10:43:38 +01:00 committed by Linus Torvalds
parent a6f37daa8b
commit fe9cd962a6
1 changed files with 44 additions and 42 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

86
drivers/char/pty.c
View file

@ -8,10 +8,12 @@
* Added TTY_DO_WRITE_WAKEUP to enable n_tty to send POLL_OUT to * Added TTY_DO_WRITE_WAKEUP to enable n_tty to send POLL_OUT to
* waiting writers -- Sapan Bhatia <sapan@corewars.org> * 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/errno.h>
#include <linux/interrupt.h> #include <linux/interrupt.h>
@ -24,26 +26,24 @@
#include <linux/init.h> #include <linux/init.h>
#include <linux/sysctl.h> #include <linux/sysctl.h>
#include <linux/device.h> #include <linux/device.h>
#include <linux/uaccess.h>
#include <asm/uaccess.h>
#include <asm/system.h>
#include <linux/bitops.h> #include <linux/bitops.h>
#include <linux/devpts_fs.h> #include <linux/devpts_fs.h>
#include <asm/system.h>
/* These are global because they are accessed in tty_io.c */ /* These are global because they are accessed in tty_io.c */
#ifdef CONFIG_UNIX98_PTYS #ifdef CONFIG_UNIX98_PTYS
struct tty_driver *ptm_driver; struct tty_driver *ptm_driver;
static struct tty_driver *pts_driver; static struct tty_driver *pts_driver;
#endif #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) BUG_ON(!tty);
return; if (tty->driver->subtype == PTY_TYPE_MASTER)
if (tty->driver->subtype == PTY_TYPE_MASTER) { WARN_ON(tty->count > 1);
if (tty->count > 1) else {
printk("master pty_close: count = %d!!\n", tty->count);
} else {
if (tty->count > 2) if (tty->count > 2)
return; 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 * The unthrottle routine is called by the line discipline to signal
* that it can receive more characters. For PTY's, the TTY_THROTTLED * 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 * 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 * characters in the queue. This is necessary since each time this
* happens, we need to wake up any sleeping processes that could be * 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() * (1) trying to send data to the pty, or (2) waiting in wait_until_sent()
* for the pty buffer to be drained. * 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; 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 * (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 * 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 * 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 * not our partners. We can't just take the other one blindly without
* risking deadlocks. * 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; struct tty_struct *to = tty->link;
int c; int c;
@ -113,7 +114,7 @@ static int pty_write(struct tty_struct * tty, const unsigned char *buf, int coun
if (c > count) if (c > count)
c = count; c = count;
to->ldisc.ops->receive_buf(to, buf, NULL, c); to->ldisc.ops->receive_buf(to, buf, NULL, c);
return 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 * 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). * to hold off writing when chars_in_buffer > WAKEUP_CHARS (== 256).
* The pty driver chars_in_buffer() Master/Slave must behave differently: * The pty driver chars_in_buffer() Master/Slave must behave differently:
* *
* The Master side needs to allow typed-ahead commands to accumulate * The Master side needs to allow typed-ahead commands to accumulate
* while being canonicalized, so we report "our buffer" as empty until * while being canonicalized, so we report "our buffer" as empty until
* some threshold is reached, and then report the count. (Any count > * some threshold is reached, and then report the count. (Any count >
* WAKEUP_CHARS is regarded by select() as "full".) To avoid deadlock * 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 * 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.) * 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 * 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 * buffer where they can be read immediately, so in this case we can
* return the true count in the buffer. * 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 */ /* The ldisc must report 0 if no characters available to be read */
count = to->ldisc.ops->chars_in_buffer(to); 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 * 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. * 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 */ /* 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; int val;
if (get_user(val,arg)) if (get_user(val, arg))
return -EFAULT; return -EFAULT;
if (val) if (val)
set_bit(TTY_PTY_LOCK, &tty->flags); 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; struct tty_struct *to = tty->link;
unsigned long flags; unsigned long flags;
if (!to) if (!to)
return; return;
if (to->ldisc.ops->flush_buffer) if (to->ldisc.ops->flush_buffer)
to->ldisc.ops->flush_buffer(to); to->ldisc.ops->flush_buffer(to);
if (to->packet) { if (to->packet) {
spin_lock_irqsave(&tty->ctrl_lock, flags); spin_lock_irqsave(&tty->ctrl_lock, flags);
tty->ctrl_status |= TIOCPKT_FLUSHWRITE; 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; int retval = -ENODEV;
@ -221,10 +223,11 @@ out:
return retval; 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 &= ~(CSIZE | PARENB);
tty->termios->c_cflag |= (CS8 | CREAD); tty->termios->c_cflag |= (CS8 | CREAD);
} }
static int pty_install(struct tty_driver *driver, struct tty_struct *tty) 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); tty_free_termios(tty);
goto free_mem_out; goto free_mem_out;
} }
/* /*
* Everything allocated ... set up the o_tty structure. * 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. * Otherwise one can eat up all kernel memory by opening /dev/ptmx repeatedly.
*/ */
int pty_limit = NR_UNIX98_PTY_DEFAULT; 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_limit_max = NR_UNIX98_PTY_MAX;
static int pty_count = 0; static int pty_count;
static struct cdev ptmx_cdev; static struct cdev ptmx_cdev;
@ -537,11 +540,10 @@ static int pty_unix98_install(struct tty_driver *driver, struct tty_struct *tty)
pty_count++; pty_count++;
return 0; return 0;
free_mem_out: free_mem_out:
kfree(o_tty->termios); pty_unix98_shutdown(o_tty);
module_put(o_tty->driver->owner); module_put(o_tty->driver->owner);
free_tty_struct(o_tty); free_tty_struct(o_tty);
kfree(tty->termios_locked); pty_unix98_shutdown(tty);
kfree(tty->termios);
free_tty_struct(tty); free_tty_struct(tty);
module_put(driver->owner); module_put(driver->owner);
return -ENOMEM; return -ENOMEM;
@ -691,13 +693,13 @@ static void __init unix98_pty_init(void)
TTY_DRIVER_DYNAMIC_DEV | TTY_DRIVER_DEVPTS_MEM; TTY_DRIVER_DYNAMIC_DEV | TTY_DRIVER_DEVPTS_MEM;
pts_driver->other = ptm_driver; pts_driver->other = ptm_driver;
tty_set_operations(pts_driver, &pty_unix98_ops); tty_set_operations(pts_driver, &pty_unix98_ops);
if (tty_register_driver(ptm_driver)) if (tty_register_driver(ptm_driver))
panic("Couldn't register Unix98 ptm driver"); panic("Couldn't register Unix98 ptm driver");
if (tty_register_driver(pts_driver)) if (tty_register_driver(pts_driver))
panic("Couldn't register Unix98 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 */ /* Now create the /dev/ptmx special device */
tty_default_fops(&ptmx_fops); tty_default_fops(&ptmx_fops);