kernel/drivers/dax/device.c, branch linux-5.1.y

mm/huge_memory: fix vmf_insert_pfn_{pmd, pud}() crash, handle unaligned addresses

2019-05-22T05:39:50Z

commit fce86ff5802bac3a7b19db171aa1949ef9caac31 upstream. Starting with c6f3c5ee40c1 ("mm/huge_memory.c: fix modifying of page protection by insert_pfn_pmd()") vmf_insert_pfn_pmd() internally calls pmdp_set_access_flags(). That helper enforces a pmd aligned @address argument via VM_BUG_ON() assertion. Update the implementation to take a 'struct vm_fault' argument directly and apply the address alignment fixup internally to fix crash signatures like: kernel BUG at arch/x86/mm/pgtable.c:515! invalid opcode: 0000 [#1] SMP NOPTI CPU: 51 PID: 43713 Comm: java Tainted: G OE 4.19.35 #1 [..] RIP: 0010:pmdp_set_access_flags+0x48/0x50 [..] Call Trace: vmf_insert_pfn_pmd+0x198/0x350 dax_iomap_fault+0xe82/0x1190 ext4_dax_huge_fault+0x103/0x1f0 ? __switch_to_asm+0x40/0x70 __handle_mm_fault+0x3f6/0x1370 ? __switch_to_asm+0x34/0x70 ? __switch_to_asm+0x40/0x70 handle_mm_fault+0xda/0x200 __do_page_fault+0x249/0x4f0 do_page_fault+0x32/0x110 ? page_fault+0x8/0x30 page_fault+0x1e/0x30 Link: http://lkml.kernel.org/r/155741946350.372037.11148198430068238140.stgit@dwillia2-desk3.amr.corp.intel.com Fixes: c6f3c5ee40c1 ("mm/huge_memory.c: fix modifying of page protection by insert_pfn_pmd()") Signed-off-by: Dan Williams Reported-by: Piotr Balcer Tested-by: Yan Ma Tested-by: Pankaj Gupta Reviewed-by: Matthew Wilcox Reviewed-by: Jan Kara Reviewed-by: Aneesh Kumar K.V Cc: Chandan Rajendra Cc: Souptick Joarder Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

device-dax: Add /sys/class/dax backwards compatibility

2019-01-07T05:41:57Z

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

device-dax: Add support for a dax override driver

2019-01-07T05:41:55Z

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

device-dax: Move resource pinning+mapping into the common driver

2019-01-07T05:26:21Z

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

device-dax: Introduce bus + driver model

2019-01-07T05:24:46Z

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

device-dax: Start defining a dax bus model

2019-01-07T05:24:46Z

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

device-dax: Remove multi-resource infrastructure

2019-01-07T05:24:46Z

The multi-resource implementation anticipated discontiguous sub-division support. That has not yet materialized, delete the infrastructure and related code. Signed-off-by: Dan Williams

device-dax: Kill dax_region base

2019-01-07T05:24:46Z

Nothing consumes this attribute of a region and devres otherwise remembers the value for de-allocation purposes. Signed-off-by: Dan Williams

device-dax: Kill dax_region ida

2019-01-07T05:24:45Z

Commit bbb3be170ac2 "device-dax: fix sysfs duplicate warnings" arranged for passing a dax instance-id to devm_create_dax_dev(), rather than generating one internally. Remove the dax_region ida and related code. Signed-off-by: Dan Williams

device-dax: Add missing address_space_operations

2018-09-22T16:07:33Z

With address_space_operations missing for device dax, namely the .set_page_dirty, we hit a kernel warning when running destructive ndctl unit test: make TESTS=device-dax check WARNING: CPU: 3 PID: 7380 at fs/buffer.c:581 __set_page_dirty+0xb1/0xc0 Setting address_space_operations to noop_set_page_dirty and noop_invalidatepage for device dax to prevent fallback to __set_page_dirty_buffers() and block_invalidatepage() respectively. Fixes: 2232c6382a ("device-dax: Enable page_mapping()") Acked-by: Jeff Moyer Reported-by: Vishal Verma Signed-off-by: Dave Jiang Signed-off-by: Dan Williams