ARCH_MEMORY_PROBE is a useful thing for testing and debugging hotplug, but being able to exercise the (arguably trickier) hot-remove path would be even more useful. Extend the feature to allow removal of offline sections to be triggered manually to aid development.
Signed-off-by: Robin Murphy <robin.mur...@arm.com> --- This is inspired by a previous proposal[1], but in coming up with a more robust interface I ended up rewriting the whole thing from scratch. The lack of documentation is semi-deliberate, since I don't like the idea of anyone actually relying on this interface as ABI, but as a handy tool it felt useful enough to be worth sharing :) Robin. [1] https://lore.kernel.org/lkml/22d34fe30df0fbacbfceeb47e20cb1184af73585.1511433386.git...@linux.vnet.ibm.com/ drivers/base/memory.c | 42 +++++++++++++++++++++++++++++++++++++++++- 1 file changed, 41 insertions(+), 1 deletion(-) diff --git a/drivers/base/memory.c b/drivers/base/memory.c index 048cbf7d5233..26344cb9f045 100644 --- a/drivers/base/memory.c +++ b/drivers/base/memory.c @@ -521,7 +521,44 @@ static ssize_t probe_store(struct device *dev, struct device_attribute *attr, } static DEVICE_ATTR_WO(probe); -#endif + +#ifdef CONFIG_MEMORY_HOTREMOVE +static ssize_t remove_store(struct device *dev, struct device_attribute *attr, + const char *buf, size_t count) +{ + struct memory_block *mem = to_memory_block(dev); + unsigned long start_pfn = section_nr_to_pfn(mem->start_section_nr); + bool remove; + int ret; + + ret = kstrtobool(buf, &remove); + if (ret) + return ret; + if (!remove) + return count; + + if (mem->state != MEM_OFFLINE) + return -EBUSY; + + ret = lock_device_hotplug_sysfs(); + if (ret) + return ret; + + if (device_remove_file_self(dev, attr)) { + __remove_memory(pfn_to_nid(start_pfn), PFN_PHYS(start_pfn), + MIN_MEMORY_BLOCK_SIZE * sections_per_block); + ret = count; + } else { + ret = -EBUSY; + } + + unlock_device_hotplug(); + return ret; +} + +static DEVICE_ATTR_WO(remove); +#endif /* CONFIG_MEMORY_HOTREMOVE */ +#endif /* CONFIG_ARCH_MEMORY_PROBE */ #ifdef CONFIG_MEMORY_FAILURE /* @@ -615,6 +652,9 @@ static struct attribute *memory_memblk_attrs[] = { &dev_attr_removable.attr, #ifdef CONFIG_MEMORY_HOTREMOVE &dev_attr_valid_zones.attr, +#ifdef CONFIG_ARCH_MEMORY_PROBE + &dev_attr_remove.attr, +#endif #endif NULL }; -- 2.20.1.dirty
