Commit e4dcee80 authored by Jeff Dike's avatar Jeff Dike Committed by Linus Torvalds
Browse files

[PATCH] uml: Add throttling to console driver



This patch adds support for throttling and unthrottling input when the tty
driver can't handle it.
Signed-off-by: default avatarJeff Dike <jdike@addtoit.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 9159c9df
......@@ -312,6 +312,32 @@ void close_chan(struct list_head *chans, int delay_free_irq)
}
}
void deactivate_chan(struct list_head *chans, int irq)
{
struct list_head *ele;
struct chan *chan;
list_for_each(ele, chans) {
chan = list_entry(ele, struct chan, list);
if(chan->enabled && chan->input)
deactivate_fd(chan->fd, irq);
}
}
void reactivate_chan(struct list_head *chans, int irq)
{
struct list_head *ele;
struct chan *chan;
list_for_each(ele, chans) {
chan = list_entry(ele, struct chan, list);
if(chan->enabled && chan->input)
reactivate_fd(chan->fd, irq);
}
}
int write_chan(struct list_head *chans, const char *buf, int len,
int write_irq)
{
......
......@@ -36,8 +36,9 @@ static void line_timer_cb(void *arg)
{
struct line *line = arg;
chan_interrupt(&line->chan_list, &line->task, line->tty,
line->driver->read_irq);
if(!line->throttled)
chan_interrupt(&line->chan_list, &line->task, line->tty,
line->driver->read_irq);
}
/* Returns the free space inside the ring buffer of this line.
......@@ -340,6 +341,30 @@ int line_ioctl(struct tty_struct *tty, struct file * file,
return ret;
}
void line_throttle(struct tty_struct *tty)
{
struct line *line = tty->driver_data;
deactivate_chan(&line->chan_list, line->driver->read_irq);
line->throttled = 1;
}
void line_unthrottle(struct tty_struct *tty)
{
struct line *line = tty->driver_data;
line->throttled = 0;
chan_interrupt(&line->chan_list, &line->task, tty,
line->driver->read_irq);
/* Maybe there is enough stuff pending that calling the interrupt
* throttles us again. In this case, line->throttled will be 1
* again and we shouldn't turn the interrupt back on.
*/
if(!line->throttled)
reactivate_chan(&line->chan_list, line->driver->read_irq);
}
static irqreturn_t line_write_interrupt(int irq, void *data,
struct pt_regs *unused)
{
......
......@@ -109,16 +109,6 @@ static void ssl_flush_buffer(struct tty_struct *tty)
return;
}
static void ssl_throttle(struct tty_struct * tty)
{
printk(KERN_ERR "Someone should implement ssl_throttle\n");
}
static void ssl_unthrottle(struct tty_struct * tty)
{
printk(KERN_ERR "Someone should implement ssl_unthrottle\n");
}
static void ssl_stop(struct tty_struct *tty)
{
printk(KERN_ERR "Someone should implement ssl_stop\n");
......@@ -145,9 +135,9 @@ static struct tty_operations ssl_ops = {
.flush_chars = line_flush_chars,
.set_termios = line_set_termios,
.ioctl = line_ioctl,
.throttle = line_throttle,
.unthrottle = line_unthrottle,
#if 0
.throttle = ssl_throttle,
.unthrottle = ssl_unthrottle,
.stop = ssl_stop,
.start = ssl_start,
.hangup = ssl_hangup,
......
......@@ -122,6 +122,8 @@ static struct tty_operations console_ops = {
.flush_chars = line_flush_chars,
.set_termios = line_set_termios,
.ioctl = line_ioctl,
.throttle = line_throttle,
.unthrottle = line_unthrottle,
};
static void uml_console_write(struct console *console, const char *string,
......
......@@ -38,6 +38,8 @@ extern int console_write_chan(struct list_head *chans, const char *buf,
int len);
extern int console_open_chan(struct line *line, struct console *co,
struct chan_opts *opts);
extern void deactivate_chan(struct list_head *chans, int irq);
extern void reactivate_chan(struct list_head *chans, int irq);
extern void chan_enable_winch(struct list_head *chans, struct tty_struct *tty);
extern void enable_chan(struct line *line);
extern void close_chan(struct list_head *chans, int delay_free_irq);
......
......@@ -38,6 +38,7 @@ struct line {
struct list_head chan_list;
int valid;
int count;
int throttled;
/*This lock is actually, mostly, local to*/
spinlock_t lock;
......@@ -60,6 +61,7 @@ struct line {
{ init_str : str, \
init_pri : INIT_STATIC, \
valid : 1, \
throttled : 0, \
lock : SPIN_LOCK_UNLOCKED, \
buffer : NULL, \
head : NULL, \
......@@ -88,6 +90,8 @@ extern void line_flush_chars(struct tty_struct *tty);
extern int line_write_room(struct tty_struct *tty);
extern int line_ioctl(struct tty_struct *tty, struct file * file,
unsigned int cmd, unsigned long arg);
extern void line_throttle(struct tty_struct *tty);
extern void line_unthrottle(struct tty_struct *tty);
extern char *add_xterm_umid(char *base);
extern int line_setup_irq(int fd, int input, int output, struct line *line,
......
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