uml: SIGIO support cleanup

Cleanup of the SIGWINCH support.

Some code and comment reformatting.

The stack used for SIGWINCH threads was leaked.  This is now fixed by storing
it with the pid and other information, and freeing it when the thread is
killed.

If something goes wrong with a WIGWINCH thread, and this is discovered in the
interrupt handler, the winch record would leak.  It is now freed, except that
the IRQ isn't freed.  This is hard to do from interrupt context.  This has the
side-effect that the IRQ system maintains a reference to the freed structure,
but that shouldn't cause a problem since the descriptor is disabled.

register_winch_irq is now much better about cleaning up after an
initialization failure.

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

1 files changed, 2 insertions, 1 deletions

diff --git a/arch/um/include/chan_user.h b/arch/um/include/chan_user.h
index 714b713e2e72..5a2263e05bb2 100644
--- a/arch/um/include/chan_user.h
+++ b/arch/um/include/chan_user.h
@@ -42,7 +42,8 @@ extern void generic_free(void *data);
 
 struct tty_struct;
 extern void register_winch(int fd,  struct tty_struct *tty);
-extern void register_winch_irq(int fd, int tty_fd, int pid, struct tty_struct *tty);
+extern void register_winch_irq(int fd, int tty_fd, int pid,
+                               struct tty_struct *tty, unsigned long stack);
 
 #define __channel_help(fn, prefix) \
 __uml_help(fn, prefix "[0-9]*=<channel description>\n" \