From e4dcee8099802c71437a15b940f66106d9f88b2f Mon Sep 17 00:00:00 2001 From: Jeff Dike Date: Fri, 6 Jan 2006 00:18:58 -0800 Subject: [PATCH] [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: Jeff Dike Cc: Paolo 'Blaisorblade' Giarrusso Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/um/drivers/chan_kern.c | 26 ++++++++++++++++++++++++++ arch/um/drivers/line.c | 29 +++++++++++++++++++++++++++-- arch/um/drivers/ssl.c | 14 ++------------ arch/um/drivers/stdio_console.c | 2 ++ arch/um/include/chan_kern.h | 2 ++ arch/um/include/line.h | 4 ++++ 6 files changed, 63 insertions(+), 14 deletions(-) diff --git a/arch/um/drivers/chan_kern.c b/arch/um/drivers/chan_kern.c index 36df55ad64c2..cd13b91b9ff6 100644 --- a/arch/um/drivers/chan_kern.c +++ b/arch/um/drivers/chan_kern.c @@ -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) { diff --git a/arch/um/drivers/line.c b/arch/um/drivers/line.c index 851a7c8caae5..b8e3e800ee41 100644 --- a/arch/um/drivers/line.c +++ b/arch/um/drivers/line.c @@ -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) { diff --git a/arch/um/drivers/ssl.c b/arch/um/drivers/ssl.c index 6823dc5d665c..a32ef55cb244 100644 --- a/arch/um/drivers/ssl.c +++ b/arch/um/drivers/ssl.c @@ -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, diff --git a/arch/um/drivers/stdio_console.c b/arch/um/drivers/stdio_console.c index 6d4edda9b510..61db8b2fc83f 100644 --- a/arch/um/drivers/stdio_console.c +++ b/arch/um/drivers/stdio_console.c @@ -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, diff --git a/arch/um/include/chan_kern.h b/arch/um/include/chan_kern.h index 84d1f64f9795..1bb5e9d94270 100644 --- a/arch/um/include/chan_kern.h +++ b/arch/um/include/chan_kern.h @@ -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); diff --git a/arch/um/include/line.h b/arch/um/include/line.h index e6cc3abfd4db..6f4d680dc1d4 100644 --- a/arch/um/include/line.h +++ b/arch/um/include/line.h @@ -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, -- 2.20.1