diff options
| -rw-r--r-- | arch/um/kernel/irq.c | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/arch/um/kernel/irq.c b/arch/um/kernel/irq.c index a1e8c460b75..8f2ed369031 100644 --- a/arch/um/kernel/irq.c +++ b/arch/um/kernel/irq.c @@ -78,6 +78,14 @@ skip: 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; |