On Wed, 2013-08-28 at 10:12 +0800, Gu Zheng wrote: > On 08/28/2013 05:38 AM, Toshi Kani wrote: : > >> > >> What about changing device_hotplug_lock and acpi_scan_lock to rwsem? like the > >> attached one(With a preliminary test, it also can make the splat go away).:) > > > > I am curious how msleep(10) & restart_syscall() work in the change > > below. Doesn't the msleep() make s_active held longer time, which can > > lead the thread holding device_hotplug_lock to wait it for deletion? > > Yes, but it can avoid busy waiting. I know, but it's kinda unfortunate to sleep with s_active held in this situation. But I am fine with the 5ms Rafael used in this latest patchset since this is a rare case anyway. > > Also, does restart_syscall() release s_active and reopen this file > > again? > > Sure, it just set a TIF_SIGPENDING flag and return an -ERESTARTNOINTR error, s_active/file > will be released/closed in the failed path. And when do_signal() catches the -ERESTARTNOINTR, > it will change the regs to restart the syscall. I see. This is a clever functionality. Thanks, -Toshi -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
