diff options
| -rw-r--r-- | arch/um/drivers/line.c | 37 |
1 files changed, 24 insertions, 13 deletions
diff --git a/arch/um/drivers/line.c b/arch/um/drivers/line.c index 2bb4c4f5dec4..e0fdffa2d542 100644 --- a/arch/um/drivers/line.c +++ b/arch/um/drivers/line.c @@ -663,11 +663,15 @@ struct tty_driver *line_register_devfs(struct lines *set, return driver; } +static spinlock_t winch_handler_lock; +LIST_HEAD(winch_handlers); + void lines_init(struct line *lines, int nlines) { struct line *line; int i; + spin_lock_init(&winch_handler_lock); for(i = 0; i < nlines; i++){ line = &lines[i]; INIT_LIST_HEAD(&line->chan_list); @@ -724,31 +728,30 @@ irqreturn_t winch_interrupt(int irq, void *data, struct pt_regs *unused) return IRQ_HANDLED; } -DECLARE_MUTEX(winch_handler_sem); -LIST_HEAD(winch_handlers); - void register_winch_irq(int fd, int tty_fd, int pid, struct tty_struct *tty) { struct winch *winch; - down(&winch_handler_sem); winch = kmalloc(sizeof(*winch), GFP_KERNEL); if (winch == NULL) { printk("register_winch_irq - kmalloc failed\n"); - goto out; + return; } + *winch = ((struct winch) { .list = LIST_HEAD_INIT(winch->list), .fd = fd, .tty_fd = tty_fd, .pid = pid, .tty = tty }); + + spin_lock(&winch_handler_lock); list_add(&winch->list, &winch_handlers); + spin_unlock(&winch_handler_lock); + if(um_request_irq(WINCH_IRQ, fd, IRQ_READ, winch_interrupt, SA_INTERRUPT | SA_SHIRQ | SA_SAMPLE_RANDOM, "winch", winch) < 0) printk("register_winch_irq - failed to register IRQ\n"); - out: - up(&winch_handler_sem); } static void unregister_winch(struct tty_struct *tty) @@ -756,7 +759,7 @@ static void unregister_winch(struct tty_struct *tty) struct list_head *ele; struct winch *winch, *found = NULL; - down(&winch_handler_sem); + spin_lock(&winch_handler_lock); list_for_each(ele, &winch_handlers){ winch = list_entry(ele, struct winch, list); if(winch->tty == tty){ @@ -764,20 +767,25 @@ static void unregister_winch(struct tty_struct *tty) break; } } - if(found == NULL) - goto out; + goto err; + + list_del(&winch->list); + spin_unlock(&winch_handler_lock); if(winch->pid != -1) os_kill_process(winch->pid, 1); free_irq(WINCH_IRQ, winch); - list_del(&winch->list); kfree(winch); - out: - up(&winch_handler_sem); + + return; +err: + spin_unlock(&winch_handler_lock); } +/* XXX: No lock as it's an exitcall... is this valid? Depending on cleanup + * order... are we sure that nothing else is done on the list? */ static void winch_cleanup(void) { struct list_head *ele; @@ -786,6 +794,9 @@ static void winch_cleanup(void) list_for_each(ele, &winch_handlers){ winch = list_entry(ele, struct winch, list); if(winch->fd != -1){ + /* Why is this different from the above free_irq(), + * which deactivates SIGIO? This searches the FD + * somewhere else and removes it from the list... */ deactivate_fd(winch->fd, WINCH_IRQ); os_close_file(winch->fd); } |