forked from luck/tmp_suning_uos_patched
pty: Coding style and polish
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
Linus Torvalds
parent
a6f37daa8b
commit
fe9cd962a6
@ -8,10 +8,12 @@
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* Added TTY_DO_WRITE_WAKEUP to enable n_tty to send POLL_OUT to
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* waiting writers -- Sapan Bhatia <sapan@corewars.org>
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*
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*
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* When reading this code see also fs/devpts. In particular note that the
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* driver_data field is used by the devpts side as a binding to the devpts
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* inode.
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*/
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#include <linux/module.h> /* For EXPORT_SYMBOL */
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#include <linux/module.h>
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#include <linux/errno.h>
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#include <linux/interrupt.h>
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@ -24,26 +26,24 @@
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#include <linux/init.h>
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#include <linux/sysctl.h>
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#include <linux/device.h>
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#include <asm/uaccess.h>
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#include <asm/system.h>
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#include <linux/uaccess.h>
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#include <linux/bitops.h>
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#include <linux/devpts_fs.h>
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#include <asm/system.h>
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/* These are global because they are accessed in tty_io.c */
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#ifdef CONFIG_UNIX98_PTYS
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struct tty_driver *ptm_driver;
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static struct tty_driver *pts_driver;
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#endif
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static void pty_close(struct tty_struct * tty, struct file * filp)
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static void pty_close(struct tty_struct *tty, struct file *filp)
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{
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if (!tty)
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return;
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if (tty->driver->subtype == PTY_TYPE_MASTER) {
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if (tty->count > 1)
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printk("master pty_close: count = %d!!\n", tty->count);
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} else {
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BUG_ON(!tty);
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if (tty->driver->subtype == PTY_TYPE_MASTER)
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WARN_ON(tty->count > 1);
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else {
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if (tty->count > 2)
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return;
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}
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@ -70,13 +70,13 @@ static void pty_close(struct tty_struct * tty, struct file * filp)
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* The unthrottle routine is called by the line discipline to signal
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* that it can receive more characters. For PTY's, the TTY_THROTTLED
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* flag is always set, to force the line discipline to always call the
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* unthrottle routine when there are fewer than TTY_THRESHOLD_UNTHROTTLE
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* unthrottle routine when there are fewer than TTY_THRESHOLD_UNTHROTTLE
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* characters in the queue. This is necessary since each time this
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* happens, we need to wake up any sleeping processes that could be
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* (1) trying to send data to the pty, or (2) waiting in wait_until_sent()
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* for the pty buffer to be drained.
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*/
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static void pty_unthrottle(struct tty_struct * tty)
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static void pty_unthrottle(struct tty_struct *tty)
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{
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struct tty_struct *o_tty = tty->link;
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@ -88,7 +88,7 @@ static void pty_unthrottle(struct tty_struct * tty)
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}
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/*
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* WSH 05/24/97: modified to
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* WSH 05/24/97: modified to
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* (1) use space in tty->flip instead of a shared temp buffer
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* The flip buffers aren't being used for a pty, so there's lots
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* of space available. The buffer is protected by a per-pty
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@ -101,7 +101,8 @@ static void pty_unthrottle(struct tty_struct * tty)
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* not our partners. We can't just take the other one blindly without
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* risking deadlocks.
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*/
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static int pty_write(struct tty_struct * tty, const unsigned char *buf, int count)
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static int pty_write(struct tty_struct *tty, const unsigned char *buf,
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int count)
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{
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struct tty_struct *to = tty->link;
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int c;
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@ -113,7 +114,7 @@ static int pty_write(struct tty_struct * tty, const unsigned char *buf, int coun
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if (c > count)
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c = count;
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to->ldisc.ops->receive_buf(to, buf, NULL, c);
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return c;
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}
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@ -129,17 +130,17 @@ static int pty_write_room(struct tty_struct *tty)
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/*
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* WSH 05/24/97: Modified for asymmetric MASTER/SLAVE behavior
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* The chars_in_buffer() value is used by the ldisc select() function
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* The chars_in_buffer() value is used by the ldisc select() function
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* to hold off writing when chars_in_buffer > WAKEUP_CHARS (== 256).
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* The pty driver chars_in_buffer() Master/Slave must behave differently:
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*
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* The Master side needs to allow typed-ahead commands to accumulate
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* while being canonicalized, so we report "our buffer" as empty until
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* some threshold is reached, and then report the count. (Any count >
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* WAKEUP_CHARS is regarded by select() as "full".) To avoid deadlock
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* the count returned must be 0 if no canonical data is available to be
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* WAKEUP_CHARS is regarded by select() as "full".) To avoid deadlock
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* the count returned must be 0 if no canonical data is available to be
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* read. (The N_TTY ldisc.chars_in_buffer now knows this.)
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*
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*
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* The Slave side passes all characters in raw mode to the Master side's
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* buffer where they can be read immediately, so in this case we can
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* return the true count in the buffer.
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@ -156,21 +157,22 @@ static int pty_chars_in_buffer(struct tty_struct *tty)
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/* The ldisc must report 0 if no characters available to be read */
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count = to->ldisc.ops->chars_in_buffer(to);
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if (tty->driver->subtype == PTY_TYPE_SLAVE) return count;
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if (tty->driver->subtype == PTY_TYPE_SLAVE)
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return count;
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/* Master side driver ... if the other side's read buffer is less than
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/* Master side driver ... if the other side's read buffer is less than
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* half full, return 0 to allow writers to proceed; otherwise return
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* the count. This leaves a comfortable margin to avoid overflow,
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* the count. This leaves a comfortable margin to avoid overflow,
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* and still allows half a buffer's worth of typed-ahead commands.
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*/
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return ((count < N_TTY_BUF_SIZE/2) ? 0 : count);
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return (count < N_TTY_BUF_SIZE/2) ? 0 : count;
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}
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/* Set the lock flag on a pty */
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static int pty_set_lock(struct tty_struct *tty, int __user * arg)
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static int pty_set_lock(struct tty_struct *tty, int __user *arg)
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{
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int val;
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if (get_user(val,arg))
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if (get_user(val, arg))
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return -EFAULT;
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if (val)
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set_bit(TTY_PTY_LOCK, &tty->flags);
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@ -183,13 +185,13 @@ static void pty_flush_buffer(struct tty_struct *tty)
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{
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struct tty_struct *to = tty->link;
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unsigned long flags;
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if (!to)
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return;
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if (to->ldisc.ops->flush_buffer)
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to->ldisc.ops->flush_buffer(to);
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if (to->packet) {
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spin_lock_irqsave(&tty->ctrl_lock, flags);
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tty->ctrl_status |= TIOCPKT_FLUSHWRITE;
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@ -198,7 +200,7 @@ static void pty_flush_buffer(struct tty_struct *tty)
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}
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}
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static int pty_open(struct tty_struct *tty, struct file * filp)
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static int pty_open(struct tty_struct *tty, struct file *filp)
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{
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int retval = -ENODEV;
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@ -221,10 +223,11 @@ static int pty_open(struct tty_struct *tty, struct file * filp)
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return retval;
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}
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static void pty_set_termios(struct tty_struct *tty, struct ktermios *old_termios)
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static void pty_set_termios(struct tty_struct *tty,
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struct ktermios *old_termios)
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{
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tty->termios->c_cflag &= ~(CSIZE | PARENB);
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tty->termios->c_cflag |= (CS8 | CREAD);
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tty->termios->c_cflag &= ~(CSIZE | PARENB);
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tty->termios->c_cflag |= (CS8 | CREAD);
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}
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static int pty_install(struct tty_driver *driver, struct tty_struct *tty)
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@ -254,7 +257,7 @@ static int pty_install(struct tty_driver *driver, struct tty_struct *tty)
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tty_free_termios(tty);
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goto free_mem_out;
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}
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/*
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* Everything allocated ... set up the o_tty structure.
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*/
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@ -381,9 +384,9 @@ static inline void legacy_pty_init(void) { }
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* Otherwise one can eat up all kernel memory by opening /dev/ptmx repeatedly.
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*/
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int pty_limit = NR_UNIX98_PTY_DEFAULT;
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static int pty_limit_min = 0;
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static int pty_limit_min;
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static int pty_limit_max = NR_UNIX98_PTY_MAX;
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static int pty_count = 0;
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static int pty_count;
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static struct cdev ptmx_cdev;
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@ -537,11 +540,10 @@ static int pty_unix98_install(struct tty_driver *driver, struct tty_struct *tty)
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pty_count++;
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return 0;
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free_mem_out:
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kfree(o_tty->termios);
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pty_unix98_shutdown(o_tty);
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module_put(o_tty->driver->owner);
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free_tty_struct(o_tty);
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kfree(tty->termios_locked);
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kfree(tty->termios);
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pty_unix98_shutdown(tty);
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free_tty_struct(tty);
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module_put(driver->owner);
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return -ENOMEM;
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@ -691,13 +693,13 @@ static void __init unix98_pty_init(void)
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TTY_DRIVER_DYNAMIC_DEV | TTY_DRIVER_DEVPTS_MEM;
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pts_driver->other = ptm_driver;
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tty_set_operations(pts_driver, &pty_unix98_ops);
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if (tty_register_driver(ptm_driver))
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panic("Couldn't register Unix98 ptm driver");
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if (tty_register_driver(pts_driver))
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panic("Couldn't register Unix98 pts driver");
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register_sysctl_table(pty_root_table);
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register_sysctl_table(pty_root_table);
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/* Now create the /dev/ptmx special device */
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tty_default_fops(&ptmx_fops);
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