[PATCH] uml: Simplify console opening/closing and irq registration

This patch simplifies the opening and closing of host console devices and the
registration and deregistration of IRQs.  The intent is to make it obvious
that an IRQ can't exist without an open file descriptor.

chan_enable will now open the channel, and when both opening and IRQ
registration are desired, this should be used.  Opening only is done for the
initial console, so that interface still needs to exist.

The free_irqs_later interface is now gone.  It was intended to avoid freeing
an IRQ while it was being processed.  It did this, but it didn't eliminate the
possiblity of free_irq being called from an interrupt, which is bad.  In its
place is a list of irqs to be freed, which is processed by the signal handler
just before exiting.  close_one_chan now disables irqs.

When a host device disappears, it is just closed, and that disables IRQs.

The device id registered with the IRQ is now the chan structure, not the tty.
This is because the interrupt arrives on a descriptor associated with the
channel.  This caused equivalent changes in the arguments to line_timer_cb.
line_disable is gone since it is not used any more.

The count field in the line structure is gone.  tty->count is used instead.

The complicated logic in sigio_handler with freeing IRQs when necessary and
making sure its idea of the next irq is correct is now much simpler.  The irq
list can't be rearranged underneath it, so it is now a simple list walk.

Signed-off-by: Jeff Dike <jdike@addtoit.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 3 insertions, 3 deletions

diff --git a/arch/um/include/line.h b/arch/um/include/line.h
index 474398ba1207..e6cc3abfd4db 100644
--- a/arch/um/include/line.h
+++ b/arch/um/include/line.h
@@ -32,6 +32,7 @@ struct line_driver {
 };
 
 struct line {
+        struct tty_struct *tty;
         char *init_str;
         int init_pri;
         struct list_head chan_list;
@@ -89,10 +90,9 @@ extern int line_ioctl(struct tty_struct *tty, struct file * file,
                       unsigned int cmd, unsigned long arg);
 
 extern char *add_xterm_umid(char *base);
-extern int line_setup_irq(int fd, int input, int output,
-                          struct tty_struct *tty);
+extern int line_setup_irq(int fd, int input, int output, struct line *line,
+                          void *data);
 extern void line_close_chan(struct line *line);
-extern void line_disable(struct tty_struct *tty, int current_irq);
 extern struct tty_driver * line_register_devfs(struct lines *set,
                                 struct line_driver *line_driver,
                                 struct tty_operations *driver,