On Mon, Nov 12, 2012 at 12:00:55PM +0800, Wen Congyang wrote: > At 11/09/2012 02:29 AM, Vasilis Liaskovitis Wrote: > > As discussed in > > https://patchwork.kernel.org/patch/1581581/ > > the driver core remove function needs to always succeed. This means we need > > to know that the device can be successfully removed before acpi_bus_trim / > > acpi_bus_hot_remove_device are called. This can cause panics when OSPM-initiated > > eject (echo 1 > /sys/bus/acpi/devices/PNP/eject) of memory devices fails, since > > the ACPI core goes ahead and ejects the device regardless of whether the memory > > is still in use or not. > > > > For this reason a new acpi_device operation called prepare_remove is introduced. > > This operation should be registered for acpi devices whose removal (from kernel > > perspective) can fail. Memory devices fall in this category. > > > > acpi_bus_hot_remove_device is changed to handle removal in 2 steps: > > - preparation for removal i.e. perform part of removal that can fail outside of > > ACPI core. Should succeed for device and all its children. > > - if above step was successfull, proceed to actual ACPI removal > > If we unbind the device from the driver, we still need to do preparation. But > you don't do it in your patch. yes, driver_unbind breaks with the current patchset. I 'll try to fix and repost. However, I think this will require a new driver-core wide prepare_remove callback (not only acpi-specific). I am not sure that would be acceptable. thanks, - Vasilis > > Thanks > Wen Congyang > > > > acpi_bus_trim is changed accordingly to handle preparation for removal and > > actual removal. > > > > With this patchset, only acpi memory devices use the new prepare_remove > > device operation. The actual memory removal (VM-related offline and other memory > > cleanups) is moved to prepare_remove. The old remove operation just cleans up > > the acpi structures. Directly ejecting PNP0C80 memory devices works safely. I > > haven't tested yet with an ACPI container which contains memory devices. > > > > Other ACPI devices (e.g. CPU) do not register prepare_remove callbacks, and > > their OSPM-side eject should not be affected. > > > > I am not happy with the name prepare_remove. Comments welcome. Let me know if I > > should work more in this direction (I think Yasuaki might also look into this > > and might have a simpler idea) > > > > Patches are on top of Rafael's linux-pm/linux-next > > > > Vasilis Liaskovitis (3): > > acpi: Introduce prepare_remove operation in acpi_device_ops > > acpi: Make acpi_bus_trim handle device removal preparation > > acpi_memhotplug: Add prepare_remove operation > > > > drivers/acpi/acpi_memhotplug.c | 24 +++++++++++++++++++++--- > > drivers/acpi/dock.c | 2 +- > > drivers/acpi/scan.c | 32 +++++++++++++++++++++++++++++--- > > drivers/pci/hotplug/acpiphp_glue.c | 4 ++-- > > drivers/pci/hotplug/sgi_hotplug.c | 2 +- > > include/acpi/acpi_bus.h | 4 +++- > > 6 files changed, 57 insertions(+), 11 deletions(-) > > > -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>