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Commit d973a77b authored by Jeff Dike's avatar Jeff Dike Committed by Linus Torvalds
Browse files

uml: irq locking commentary 



Locking commentary.

Signed-off-by: default avatarJeff Dike <jdike@linux.intel.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 1d1497e1

arch/um/kernel/irq.c

+15 −0
Original line number Diff line number Diff line
@@ -78,6 +78,14 @@ int show_interrupts(struct seq_file *p, void *v) 
	return 0;

}



/*

 * This list is accessed under irq_lock, except in sigio_handler,

 * where it is safe from being modified.  IRQ handlers won't change it -

 * if an IRQ source has vanished, it will be freed by free_irqs just

 * before returning from sigio_handler.  That will process a separate

 * list of irqs to free, with its own locking, coming back here to

 * remove list elements, taking the irq_lock to do so.

 */

static struct irq_fd *active_fds = NULL;

static struct irq_fd **last_irq_ptr = &active_fds;
@@ -243,6 +251,7 @@ void free_irq_by_fd(int fd) 
	free_irq_by_cb(same_fd, &fd);

}



/* Must be called with irq_lock held */

static struct irq_fd *find_irq_by_fd(int fd, int irqnum, int *index_out)

{

	struct irq_fd *irq;
@@ -308,6 +317,12 @@ void deactivate_fd(int fd, int irqnum) 
	ignore_sigio_fd(fd);

}



/*

 * Called just before shutdown in order to provide a clean exec

 * environment in case the system is rebooting.  No locking because

 * that would cause a pointless shutdown hang if something hadn't

 * released the lock.

 */

int deactivate_all_fds(void)

{

	struct irq_fd *irq;