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 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(-) -- 1.7.9 -- 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>