[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>
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