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path: root/drivers/dax/bus.c
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2019-01-06device-dax: Add /sys/class/dax backwards compatibilityDan Williams
On the expectation that some environments may not upgrade libdaxctl (userspace component that depends on the /sys/class/dax hierarchy), provide a default / legacy dax_pmem_compat driver. The dax_pmem_compat driver implements the original /sys/class/dax sysfs layout rather than /sys/bus/dax. When userspace is upgraded it can blacklist this module and switch to the dax_pmem driver going forward. CONFIG_DEV_DAX_PMEM_COMPAT and supporting code will be deleted according to the dax_pmem entry in Documentation/ABI/obsolete/. Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2019-01-06device-dax: Add support for a dax override driverDan Williams
Introduce the 'new_id' concept for enabling a custom device-driver attach policy for dax-bus drivers. The intended use is to have a mechanism for hot-plugging device-dax ranges into the page allocator on-demand. With this in place the default policy of using device-dax for performance differentiated memory can be overridden by user-space policy that can arrange for the memory range to be managed as 'System RAM' with user-defined NUMA and other performance attributes. Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2019-01-06device-dax: Move resource pinning+mapping into the common driverDan Williams
Move the responsibility of calling devm_request_resource() and devm_memremap_pages() into the common device-dax driver. This is another preparatory step to allowing an alternate personality driver for a device-dax range. Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2019-01-06device-dax: Introduce bus + driver modelDan Williams
In support of multiple device-dax instances per device-dax-region and allowing the 'kmem' driver to attach to dax-instances instead of the current device-node access, convert the dax sub-system from a class to a bus. Recall that the kmem driver takes reserved / special purpose memories and assigns them to be managed by the core-mm. Aside from the fact the device-dax instances are registered and probed on a bus, two other lifetime-management changes are made: 1/ Delay attaching a cdev until driver probe time 2/ A new run_dax() helper is introduced to allow restoring dax-operation after a kill_dax() event. So, at driver ->probe() time we run_dax() and at ->remove() time we kill_dax() and invalidate all mappings. Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2019-01-06device-dax: Start defining a dax bus modelDan Williams
Towards eliminating the dax_class, move the dax-device-attribute enabling to a new bus.c file in the core. The amount of code thrash of sub-sequent patches is reduced as no logic changes are made, just pure code movement. A temporary export of unregister_dex_dax() and dax_attribute_groups is needed to preserve compilation, but those symbols become static again in a follow-on patch. Signed-off-by: Dan Williams <dan.j.williams@intel.com>