linux/drivers/dax, branch v5.7

device-dax: don't leak kernel memory to user space after unloading kmem

2020-05-23T17:26:31Z

Assume we have kmem configured and loaded: [root@localhost ~]# cat /proc/iomem ... 140000000-33fffffff : Persistent Memory$ 140000000-1481fffff : namespace0.0 150000000-33fffffff : dax0.0 150000000-33fffffff : System RAM Assume we try to unload kmem. This force-unloading will work, even if memory cannot get removed from the system. [root@localhost ~]# rmmod kmem [ 86.380228] removing memory fails, because memory [0x0000000150000000-0x0000000157ffffff] is onlined ... [ 86.431225] kmem dax0.0: DAX region [mem 0x150000000-0x33fffffff] cannot be hotremoved until the next reboot Now, we can reconfigure the namespace: [root@localhost ~]# ndctl create-namespace --force --reconfig=namespace0.0 --mode=devdax [ 131.409351] nd_pmem namespace0.0: could not reserve region [mem 0x140000000-0x33fffffff]dax [ 131.410147] nd_pmem: probe of namespace0.0 failed with error -16namespace0.0 --mode=devdax ... This fails as expected due to the busy memory resource, and the memory cannot be used. However, the dax0.0 device is removed, and along its name. The name of the memory resource now points at freed memory (name of the device): [root@localhost ~]# cat /proc/iomem ... 140000000-33fffffff : Persistent Memory 140000000-1481fffff : namespace0.0 150000000-33fffffff : �_�^7_��/_��wR��WQ��^�� ... 150000000-33fffffff : System RAM We have to make sure to duplicate the string. While at it, remove the superfluous setting of the name and fixup a stale comment. Fixes: 9f960da72b25 ("device-dax: "Hotremove" persistent memory that is used like normal RAM") Signed-off-by: David Hildenbrand Signed-off-by: Andrew Morton Cc: Dan Williams Cc: Vishal Verma Cc: Dave Jiang Cc: Pavel Tatashin Cc: Andrew Morton Cc: [5.3] Link: http://lkml.kernel.org/r/20200508084217.9160-2-david@redhat.com Signed-off-by: Linus Torvalds

dax: Move mandatory ->zero_page_range() check in alloc_dax()

2020-04-03T02:15:03Z

zero_page_range() dax operation is mandatory for dax devices. Right now that check happens in dax_zero_page_range() function. Dan thinks that's too late and its better to do the check earlier in alloc_dax(). I also modified alloc_dax() to return pointer with error code in it in case of failure. Right now it returns NULL and caller assumes failure happened due to -ENOMEM. But with this ->zero_page_range() check, I need to return -EINVAL instead. Signed-off-by: Vivek Goyal Link: https://lore.kernel.org/r/20200401161125.GB9398@redhat.com Signed-off-by: Dan Williams

dax, pmem: Add a dax operation zero_page_range

2020-04-03T02:15:03Z

Add a dax operation zero_page_range, to zero a page. This will also clear any known poison in the page being zeroed. As of now, zeroing of one page is allowed in a single call. There are no callers which are trying to zero more than a page in a single call. Once we grow the callers which zero more than a page in single call, we can add that support. Primary reason for not doing that yet is that this will add little complexity in dm implementation where a range might be spanning multiple underlying targets and one will have to split the range into multiple sub ranges and call zero_page_range() on individual targets. Suggested-by: Christoph Hellwig Signed-off-by: Vivek Goyal Reviewed-by: Pankaj Gupta Link: https://lore.kernel.org/r/20200228163456.1587-3-vgoyal@redhat.com Signed-off-by: Dan Williams

dax: Get rid of fs_dax_get_by_host() helper

2020-01-16T17:52:27Z

Looks like nobody is using fs_dax_get_by_host() except fs_dax_get_by_bdev() and it can easily use dax_get_by_host() instead. IIUC, fs_dax_get_by_host() was only introduced so that one could compile with CONFIG_FS_DAX=n and CONFIG_DAX=m. fs_dax_get_by_bdev() achieves the same purpose and hence it looks like fs_dax_get_by_host() is not needed anymore. Signed-off-by: Vivek Goyal Reviewed-by: Christoph Hellwig Link: https://lore.kernel.org/r/20200106181117.GA16248@redhat.com Signed-off-by: Dan Williams

Merge tag 'libnvdimm-for-5.5' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm

2019-12-02T02:43:25Z

Pull libnvdimm updates from Dan Williams: "The highlight this cycle is continuing integration fixes for PowerPC and some resulting optimizations. Summary: - Updates to better support vmalloc space restrictions on PowerPC platforms. - Cleanups to move common sysfs attributes to core 'struct device_type' objects. - Export the 'target_node' attribute (the effective numa node if pmem is marked online) for regions and namespaces. - Miscellaneous fixups and optimizations" * tag 'libnvdimm-for-5.5' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm: (21 commits) MAINTAINERS: Remove Keith from NVDIMM maintainers libnvdimm: Export the target_node attribute for regions and namespaces dax: Add numa_node to the default device-dax attributes libnvdimm: Simplify root read-only definition for the 'resource' attribute dax: Simplify root read-only definition for the 'resource' attribute dax: Create a dax device_type libnvdimm: Move nvdimm_bus_attribute_group to device_type libnvdimm: Move nvdimm_attribute_group to device_type libnvdimm: Move nd_mapping_attribute_group to device_type libnvdimm: Move nd_region_attribute_group to device_type libnvdimm: Move nd_numa_attribute_group to device_type libnvdimm: Move nd_device_attribute_group to device_type libnvdimm: Move region attribute group definition libnvdimm: Move attribute groups to device type libnvdimm: Remove prototypes for nonexistent functions libnvdimm/btt: fix variable 'rc' set but not used libnvdimm/pmem: Delete include of nd-core.h libnvdimm/namespace: Differentiate between probe mapping and runtime mapping libnvdimm/pfn_dev: Don't clear device memmap area during generic namespace probe libnvdimm: Trivial comment fix ...

dax: Add numa_node to the default device-dax attributes

2019-11-19T17:52:12Z

It is confusing that device-dax instances publish a 'target_node' attribute, but not a 'numa_node'. The 'numa_node' information is available elsewhere in the sysfs device hierarchy, but it is not obvious and not reliable from one device-dax instance-type (e.g. child devices of nvdimm namespaces) to the next (e.g. 'hmem' devices defined by EFI Specific Purpose Memory and the ACPI HMAT). Cc: Ira Weiny Cc: Vishal Verma Signed-off-by: Dan Williams Reviewed-by: Aneesh Kumar K.V Link: https://lore.kernel.org/r/157309906102.1582359.4262088001244476001.stgit@dwillia2-desk3.amr.corp.intel.com

dax: Simplify root read-only definition for the 'resource' attribute

2019-11-19T17:52:12Z

Rather than update the permission in ->is_visible() set the permission directly at declaration time. Cc: Ira Weiny Cc: Vishal Verma Signed-off-by: Dan Williams Reviewed-by: Aneesh Kumar K.V Link: https://lore.kernel.org/r/157309904959.1582359.7281180042781955506.stgit@dwillia2-desk3.amr.corp.intel.com

dax: Create a dax device_type

2019-11-19T17:52:12Z

Move the open coded release method and attribute groups to a 'struct device_type' instance. Cc: Ira Weiny Cc: Vishal Verma Signed-off-by: Dan Williams Reviewed-by: Aneesh Kumar K.V Link: https://lore.kernel.org/r/157309904365.1582359.5451327195246651379.stgit@dwillia2-desk3.amr.corp.intel.com

libnvdimm/namespace: Differentiate between probe mapping and runtime mapping

2019-11-15T03:08:47Z

The nvdimm core currently maps the full namespace to an ioremap range while probing the namespace mode. This can result in probe failures on architectures that have limited ioremap space. For example, with a large btt namespace that consumes most of I/O remap range, depending on the sequence of namespace initialization, the user can find a pfn namespace initialization failure due to unavailable I/O remap space which nvdimm core uses for temporary mapping. nvdimm core can avoid this failure by only mapping the reserved info block area to check for pfn superblock type and map the full namespace resource only before using the namespace. Given that personalities like BTT can be layered on top of any namespace type create a generic form of devm_nsio_enable (devm_namespace_enable) and use it inside the per-personality attach routines. Now devm_namespace_enable() is always paired with disable unless the mapping is going to be used for long term runtime access. Signed-off-by: Aneesh Kumar K.V Link: https://lore.kernel.org/r/20191017073308.32645-1-aneesh.kumar@linux.ibm.com [djbw: reworks to move devm_namespace_{en,dis}able into *attach helpers] Reported-by: kbuild test robot Link: https://lore.kernel.org/r/20191031105741.102793-2-aneesh.kumar@linux.ibm.com Signed-off-by: Dan Williams

device-dax: Add a driver for "hmem" devices

2019-11-07T14:45:00Z

Platform firmware like EFI/ACPI may publish "hmem" platform devices. Such a device is a performance differentiated memory range likely reserved for an application specific use case. The driver gives access to 100% of the capacity via a device-dax mmap instance by default. However, if over-subscription and other kernel memory management is desired the resulting dax device can be assigned to the core-mm via the kmem driver. This consumes "hmem" devices the producer of "hmem" devices is saved for a follow-on patch so that it can reference the new CONFIG_DEV_DAX_HMEM symbol to gate performing the enumeration work. Reported-by: kbuild test robot Reviewed-by: Dave Hansen Signed-off-by: Dan Williams Acked-by: Thomas Gleixner Signed-off-by: Rafael J. Wysocki