On Fri, Aug 09, 2019 at 01:32:16PM -0600, Keith Busch wrote: > On Fri, Aug 09, 2019 at 12:28:43PM +0200, Lukas Wunner wrote: > > A sysfs request to enable or disable a PCIe hotplug slot should not > > return before it has been carried out. That is sought to be achieved > > by waiting until the controller's "pending_events" have been cleared. > > > > However the IRQ thread pciehp_ist() clears the "pending_events" before > > it acts on them. If pciehp_sysfs_enable_slot() / _disable_slot() happen > > to check the "pending_events" after they have been cleared but while > > pciehp_ist() is still running, the functions may return prematurely > > with an incorrect return value. > > > > Fix by introducing an "ist_running" flag which must be false before a > > sysfs request is allowed to return. > > Can you instead just call synchronize_irq(ctrl->pcie->irq) after the > pending events is cleared? You mean call synchronize_irq() from pciehp_sysfs_enable_slot() / disable_slot()? That's a good idea, let me think that through and try to make it work that way. Thanks! Lukas
