Commit 2870f6c4 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge branch 'libnvdimm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm 

Pull libnvdimm fixes from Dan Williams:

 - three fixes tagged for -stable including a crash fix, simple
   performance tweak, and an invalid i/o error.

 - build regression fix for the nvdimm unit tests

 - nvdimm documentation update

* 'libnvdimm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm:
  dax: fix __dax_pmd_fault crash
  libnvdimm: documentation clarifications
  libnvdimm, pmem: fix size trim in pmem_direct_access()
  libnvdimm, e820: fix numa node for e820-type-12 pmem ranges
  tools/testing/nvdimm, acpica: fix flag rename build breakage
parents 934f98d7 152d7bd8

Documentation/nvdimm/nvdimm.txt

+28 −21
Original line number Diff line number Diff line
@@ -62,6 +62,12 @@ DAX: File system extensions to bypass the page cache and block layer to 
mmap persistent memory, from a PMEM block device, directly into a

process address space.



DSM: Device Specific Method: ACPI method to to control specific

device - in this case the firmware.



DCR: NVDIMM Control Region Structure defined in ACPI 6 Section 5.2.25.5.

It defines a vendor-id, device-id, and interface format for a given DIMM.



BTT: Block Translation Table: Persistent memory is byte addressable.

Existing software may have an expectation that the power-fail-atomicity

of writes is at least one sector, 512 bytes.  The BTT is an indirection
@@ -133,16 +139,16 @@ device driver: 
    registered, can be immediately attached to nd_pmem.



    2. BLK (nd_blk.ko): This driver performs I/O using a set of platform

    defined apertures.  A set of apertures will all access just one DIMM.

    Multiple windows allow multiple concurrent accesses, much like

    defined apertures.  A set of apertures will access just one DIMM.

    Multiple windows (apertures) allow multiple concurrent accesses, much like

    tagged-command-queuing, and would likely be used by different threads or

    different CPUs.



    The NFIT specification defines a standard format for a BLK-aperture, but

    the spec also allows for vendor specific layouts, and non-NFIT BLK

    implementations may other designs for BLK I/O.  For this reason "nd_blk"

    calls back into platform-specific code to perform the I/O.  One such

    implementation is defined in the "Driver Writer's Guide" and "DSM

    implementations may have other designs for BLK I/O.  For this reason

    "nd_blk" calls back into platform-specific code to perform the I/O.

    One such implementation is defined in the "Driver Writer's Guide" and "DSM

    Interface Example".
@@ -152,7 +158,7 @@ Why BLK? 
While PMEM provides direct byte-addressable CPU-load/store access to

NVDIMM storage, it does not provide the best system RAS (recovery,

availability, and serviceability) model.  An access to a corrupted

system-physical-address address causes a cpu exception while an access

system-physical-address address causes a CPU exception while an access

to a corrupted address through an BLK-aperture causes that block window

to raise an error status in a register.  The latter is more aligned with

the standard error model that host-bus-adapter attached disks present.
@@ -162,7 +168,7 @@ data could be interleaved in an opaque hardware specific manner across 
several DIMMs.



PMEM vs BLK

BLK-apertures solve this RAS problem, but their presence is also the

BLK-apertures solve these RAS problems, but their presence is also the

major contributing factor to the complexity of the ND subsystem.  They

complicate the implementation because PMEM and BLK alias in DPA space.

Any given DIMM's DPA-range may contribute to one or more
@@ -220,8 +226,8 @@ socket. Each unique interface (BLK or PMEM) to DPA space is identified 
by a region device with a dynamically assigned id (REGION0 - REGION5).



    1. The first portion of DIMM0 and DIMM1 are interleaved as REGION0. A

    single PMEM namespace is created in the REGION0-SPA-range that spans

    DIMM0 and DIMM1 with a user-specified name of "pm0.0". Some of that

    single PMEM namespace is created in the REGION0-SPA-range that spans most

    of DIMM0 and DIMM1 with a user-specified name of "pm0.0". Some of that

    interleaved system-physical-address range is reclaimed as BLK-aperture

    accessed space starting at DPA-offset (a) into each DIMM.  In that

    reclaimed space we create two BLK-aperture "namespaces" from REGION2 and
@@ -230,13 +236,13 @@ by a region device with a dynamically assigned id (REGION0 - REGION5). 


    2. In the last portion of DIMM0 and DIMM1 we have an interleaved

    system-physical-address range, REGION1, that spans those two DIMMs as

    well as DIMM2 and DIMM3.  Some of REGION1 allocated to a PMEM namespace

    named "pm1.0" the rest is reclaimed in 4 BLK-aperture namespaces (for

    well as DIMM2 and DIMM3.  Some of REGION1 is allocated to a PMEM namespace

    named "pm1.0", the rest is reclaimed in 4 BLK-aperture namespaces (for

    each DIMM in the interleave set), "blk2.1", "blk3.1", "blk4.0", and

    "blk5.0".



    3. The portion of DIMM2 and DIMM3 that do not participate in the REGION1

    interleaved system-physical-address range (i.e. the DPA address below

    interleaved system-physical-address range (i.e. the DPA address past

    offset (b) are also included in the "blk4.0" and "blk5.0" namespaces.

    Note, that this example shows that BLK-aperture namespaces don't need to

    be contiguous in DPA-space.
@@ -252,15 +258,15 @@ LIBNVDIMM Kernel Device Model and LIBNDCTL Userspace API 


What follows is a description of the LIBNVDIMM sysfs layout and a

corresponding object hierarchy diagram as viewed through the LIBNDCTL

api.  The example sysfs paths and diagrams are relative to the Example

API.  The example sysfs paths and diagrams are relative to the Example

NVDIMM Platform which is also the LIBNVDIMM bus used in the LIBNDCTL unit

test.



LIBNDCTL: Context

Every api call in the LIBNDCTL library requires a context that holds the

Every API call in the LIBNDCTL library requires a context that holds the

logging parameters and other library instance state.  The library is

based on the libabc template:

https://git.kernel.org/cgit/linux/kernel/git/kay/libabc.git/

https://git.kernel.org/cgit/linux/kernel/git/kay/libabc.git



LIBNDCTL: instantiate a new library context example
@@ -509,7 +515,7 @@ At first glance it seems since NFIT defines just PMEM and BLK interface 
types that we should simply name REGION devices with something derived

from those type names.  However, the ND subsystem explicitly keeps the

REGION name generic and expects userspace to always consider the

region-attributes for 4 reasons:

region-attributes for four reasons:



    1. There are already more than two REGION and "namespace" types.  For

    PMEM there are two subtypes.  As mentioned previously we have PMEM where
@@ -698,8 +704,8 @@ static int configure_namespace(struct ndctl_region *region, 


Why the Term "namespace"?



    1. Why not "volume" for instance?  "volume" ran the risk of confusing ND

    as a volume manager like device-mapper.

    1. Why not "volume" for instance?  "volume" ran the risk of confusing

    ND (libnvdimm subsystem) to a volume manager like device-mapper.



    2. The term originated to describe the sub-devices that can be created

    within a NVME controller (see the nvme specification:
@@ -774,13 +780,14 @@ block" needs to be destroyed. Note, that to destroy a BTT the media 
needs to be written in raw mode.  By default, the kernel will autodetect

the presence of a BTT and disable raw mode.  This autodetect behavior

can be suppressed by enabling raw mode for the namespace via the

ndctl_namespace_set_raw_mode() api.

ndctl_namespace_set_raw_mode() API.





Summary LIBNDCTL Diagram

------------------------



For the given example above, here is the view of the objects as seen by the LIBNDCTL api:

For the given example above, here is the view of the objects as seen by the

LIBNDCTL API:

            +---+

            |CTX|    +---------+   +--------------+  +---------------+

            +-+-+  +-> REGION0 +---> NAMESPACE0.0 +--> PMEM8 "pm0.0" |

drivers/nvdimm/e820.c

+14 −1
Original line number Diff line number Diff line
@@ -3,6 +3,7 @@ 
 * Copyright (c) 2015, Intel Corporation.

 */

#include <linux/platform_device.h>

#include <linux/memory_hotplug.h>

#include <linux/libnvdimm.h>

#include <linux/module.h>
@@ -25,6 +26,18 @@ static int e820_pmem_remove(struct platform_device *pdev) 
	return 0;

}



#ifdef CONFIG_MEMORY_HOTPLUG

static int e820_range_to_nid(resource_size_t addr)

{

	return memory_add_physaddr_to_nid(addr);

}

#else

static int e820_range_to_nid(resource_size_t addr)

{

	return NUMA_NO_NODE;

}

#endif



static int e820_pmem_probe(struct platform_device *pdev)

{

	static struct nvdimm_bus_descriptor nd_desc;
@@ -48,7 +61,7 @@ static int e820_pmem_probe(struct platform_device *pdev) 
		memset(&ndr_desc, 0, sizeof(ndr_desc));

		ndr_desc.res = p;

		ndr_desc.attr_groups = e820_pmem_region_attribute_groups;

		ndr_desc.numa_node = NUMA_NO_NODE;

		ndr_desc.numa_node = e820_range_to_nid(p->start);

		set_bit(ND_REGION_PAGEMAP, &ndr_desc.flags);

		if (!nvdimm_pmem_region_create(nvdimm_bus, &ndr_desc))

			goto err;

drivers/nvdimm/pmem.c

+2 −13
Original line number Diff line number Diff line
@@ -105,22 +105,11 @@ static long pmem_direct_access(struct block_device *bdev, sector_t sector, 
{

	struct pmem_device *pmem = bdev->bd_disk->private_data;

	resource_size_t offset = sector * 512 + pmem->data_offset;

	resource_size_t size;



	if (pmem->data_offset) {

		/*

		 * Limit the direct_access() size to what is covered by

		 * the memmap

		 */

		size = (pmem->size - offset) & ~ND_PFN_MASK;

	} else

		size = pmem->size - offset;



	/* FIXME convert DAX to comprehend that this mapping has a lifetime */

	*kaddr = pmem->virt_addr + offset;

	*pfn = (pmem->phys_addr + offset) >> PAGE_SHIFT;



	return size;

	return pmem->size - offset;

}



static const struct block_device_operations pmem_fops = {

fs/dax.c

+7 −0
Original line number Diff line number Diff line
@@ -629,6 +629,13 @@ int __dax_pmd_fault(struct vm_area_struct *vma, unsigned long address, 
		if ((length < PMD_SIZE) || (pfn & PG_PMD_COLOUR))

			goto fallback;



		/*

		 * TODO: teach vmf_insert_pfn_pmd() to support

		 * 'pte_special' for pmds

		 */

		if (pfn_valid(pfn))

			goto fallback;



		if (buffer_unwritten(&bh) || buffer_new(&bh)) {

			int i;

			for (i = 0; i < PTRS_PER_PMD; i++)

tools/testing/nvdimm/test/nfit.c

+1 −1
Original line number Diff line number Diff line
@@ -1135,7 +1135,7 @@ static void nfit_test1_setup(struct nfit_test *t) 
	memdev->interleave_ways = 1;

	memdev->flags = ACPI_NFIT_MEM_SAVE_FAILED | ACPI_NFIT_MEM_RESTORE_FAILED

		| ACPI_NFIT_MEM_FLUSH_FAILED | ACPI_NFIT_MEM_HEALTH_OBSERVED

		| ACPI_NFIT_MEM_ARMED;

		| ACPI_NFIT_MEM_NOT_ARMED;



	offset += sizeof(*memdev);

	/* dcr-descriptor0 */

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