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libnvdimm, pfn: 'struct page' provider infrastructure
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Implement the base infrastructure for libnvdimm PFN devices. Similar to
BTT devices they take a namespace as a backing device and layer
functionality on top. In this case the functionality is reserving space
for an array of 'struct page' entries to be handed out through
pfn_to_page(). For now this is just the basic libnvdimm-device-model for
configuring the base PFN device.

As the namespace claiming mechanism for PFN devices is mostly identical
to BTT devices drivers/nvdimm/claim.c is created to house the common
bits.

Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
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Dan Williams committed Aug 29, 2015
1 parent 96601ad commit e145574
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Showing 13 changed files with 719 additions and 177 deletions.
22 changes: 22 additions & 0 deletions drivers/nvdimm/Kconfig
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Original file line number Diff line number Diff line change
Expand Up @@ -21,6 +21,7 @@ config BLK_DEV_PMEM
default LIBNVDIMM
depends on HAS_IOMEM
select ND_BTT if BTT
select ND_PFN if NVDIMM_PFN
help
Memory ranges for PMEM are described by either an NFIT
(NVDIMM Firmware Interface Table, see CONFIG_NFIT_ACPI), a
Expand All @@ -47,12 +48,16 @@ config ND_BLK
(CONFIG_ACPI_NFIT), or otherwise exposes BLK-mode
capabilities.

config ND_CLAIM
bool

config ND_BTT
tristate

config BTT
bool "BTT: Block Translation Table (atomic sector updates)"
default y if LIBNVDIMM
select ND_CLAIM
help
The Block Translation Table (BTT) provides atomic sector
update semantics for persistent memory devices, so that
Expand All @@ -65,4 +70,21 @@ config BTT

Select Y if unsure

config ND_PFN
tristate

config NVDIMM_PFN
bool "PFN: Map persistent (device) memory"
default LIBNVDIMM
select ND_CLAIM
help
Map persistent memory, i.e. advertise it to the memory
management sub-system. By default persistent memory does
not support direct I/O, RDMA, or any other usage that
requires a 'struct page' to mediate an I/O request. This
driver allocates and initializes the infrastructure needed
to support those use cases.

Select Y if unsure

endif
2 changes: 2 additions & 0 deletions drivers/nvdimm/Makefile
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Original file line number Diff line number Diff line change
Expand Up @@ -20,4 +20,6 @@ libnvdimm-y += region_devs.o
libnvdimm-y += region.o
libnvdimm-y += namespace_devs.o
libnvdimm-y += label.o
libnvdimm-$(CONFIG_ND_CLAIM) += claim.o
libnvdimm-$(CONFIG_BTT) += btt_devs.o
libnvdimm-$(CONFIG_NVDIMM_PFN) += pfn_devs.o
6 changes: 3 additions & 3 deletions drivers/nvdimm/btt.c
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Original file line number Diff line number Diff line change
Expand Up @@ -731,6 +731,7 @@ static int create_arenas(struct btt *btt)
static int btt_arena_write_layout(struct arena_info *arena)
{
int ret;
u64 sum;
struct btt_sb *super;
struct nd_btt *nd_btt = arena->nd_btt;
const u8 *parent_uuid = nd_dev_to_uuid(&nd_btt->ndns->dev);
Expand Down Expand Up @@ -770,7 +771,8 @@ static int btt_arena_write_layout(struct arena_info *arena)
super->info2off = cpu_to_le64(arena->info2off - arena->infooff);

super->flags = 0;
super->checksum = cpu_to_le64(nd_btt_sb_checksum(super));
sum = nd_sb_checksum((struct nd_gen_sb *) super);
super->checksum = cpu_to_le64(sum);

ret = btt_info_write(arena, super);

Expand Down Expand Up @@ -1422,8 +1424,6 @@ static int __init nd_btt_init(void)
{
int rc;

BUILD_BUG_ON(sizeof(struct btt_sb) != SZ_4K);

btt_major = register_blkdev(0, "btt");
if (btt_major < 0)
return btt_major;
Expand Down
172 changes: 8 additions & 164 deletions drivers/nvdimm/btt_devs.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -21,63 +21,13 @@
#include "btt.h"
#include "nd.h"

static void __nd_btt_detach_ndns(struct nd_btt *nd_btt)
{
struct nd_namespace_common *ndns = nd_btt->ndns;

dev_WARN_ONCE(&nd_btt->dev, !mutex_is_locked(&ndns->dev.mutex)
|| ndns->claim != &nd_btt->dev,
"%s: invalid claim\n", __func__);
ndns->claim = NULL;
nd_btt->ndns = NULL;
put_device(&ndns->dev);
}

static void nd_btt_detach_ndns(struct nd_btt *nd_btt)
{
struct nd_namespace_common *ndns = nd_btt->ndns;

if (!ndns)
return;
get_device(&ndns->dev);
device_lock(&ndns->dev);
__nd_btt_detach_ndns(nd_btt);
device_unlock(&ndns->dev);
put_device(&ndns->dev);
}

static bool __nd_btt_attach_ndns(struct nd_btt *nd_btt,
struct nd_namespace_common *ndns)
{
if (ndns->claim)
return false;
dev_WARN_ONCE(&nd_btt->dev, !mutex_is_locked(&ndns->dev.mutex)
|| nd_btt->ndns,
"%s: invalid claim\n", __func__);
ndns->claim = &nd_btt->dev;
nd_btt->ndns = ndns;
get_device(&ndns->dev);
return true;
}

static bool nd_btt_attach_ndns(struct nd_btt *nd_btt,
struct nd_namespace_common *ndns)
{
bool claimed;

device_lock(&ndns->dev);
claimed = __nd_btt_attach_ndns(nd_btt, ndns);
device_unlock(&ndns->dev);
return claimed;
}

static void nd_btt_release(struct device *dev)
{
struct nd_region *nd_region = to_nd_region(dev->parent);
struct nd_btt *nd_btt = to_nd_btt(dev);

dev_dbg(dev, "%s\n", __func__);
nd_btt_detach_ndns(nd_btt);
nd_detach_ndns(&nd_btt->dev, &nd_btt->ndns);
ida_simple_remove(&nd_region->btt_ida, nd_btt->id);
kfree(nd_btt->uuid);
kfree(nd_btt);
Expand Down Expand Up @@ -172,104 +122,15 @@ static ssize_t namespace_show(struct device *dev,
return rc;
}

static int namespace_match(struct device *dev, void *data)
{
char *name = data;

return strcmp(name, dev_name(dev)) == 0;
}

static bool is_nd_btt_idle(struct device *dev)
{
struct nd_region *nd_region = to_nd_region(dev->parent);
struct nd_btt *nd_btt = to_nd_btt(dev);

if (nd_region->btt_seed == dev || nd_btt->ndns || dev->driver)
return false;
return true;
}

static ssize_t __namespace_store(struct device *dev,
struct device_attribute *attr, const char *buf, size_t len)
{
struct nd_btt *nd_btt = to_nd_btt(dev);
struct nd_namespace_common *ndns;
struct device *found;
char *name;

if (dev->driver) {
dev_dbg(dev, "%s: -EBUSY\n", __func__);
return -EBUSY;
}

name = kstrndup(buf, len, GFP_KERNEL);
if (!name)
return -ENOMEM;
strim(name);

if (strncmp(name, "namespace", 9) == 0 || strcmp(name, "") == 0)
/* pass */;
else {
len = -EINVAL;
goto out;
}

ndns = nd_btt->ndns;
if (strcmp(name, "") == 0) {
/* detach the namespace and destroy / reset the btt device */
nd_btt_detach_ndns(nd_btt);
if (is_nd_btt_idle(dev))
nd_device_unregister(dev, ND_ASYNC);
else {
nd_btt->lbasize = 0;
kfree(nd_btt->uuid);
nd_btt->uuid = NULL;
}
goto out;
} else if (ndns) {
dev_dbg(dev, "namespace already set to: %s\n",
dev_name(&ndns->dev));
len = -EBUSY;
goto out;
}

found = device_find_child(dev->parent, name, namespace_match);
if (!found) {
dev_dbg(dev, "'%s' not found under %s\n", name,
dev_name(dev->parent));
len = -ENODEV;
goto out;
}

ndns = to_ndns(found);
if (__nvdimm_namespace_capacity(ndns) < SZ_16M) {
dev_dbg(dev, "%s too small to host btt\n", name);
len = -ENXIO;
goto out_attach;
}

WARN_ON_ONCE(!is_nvdimm_bus_locked(&nd_btt->dev));
if (!nd_btt_attach_ndns(nd_btt, ndns)) {
dev_dbg(dev, "%s already claimed\n",
dev_name(&ndns->dev));
len = -EBUSY;
}

out_attach:
put_device(&ndns->dev); /* from device_find_child */
out:
kfree(name);
return len;
}

static ssize_t namespace_store(struct device *dev,
struct device_attribute *attr, const char *buf, size_t len)
{
struct nd_btt *nd_btt = to_nd_btt(dev);
ssize_t rc;

nvdimm_bus_lock(dev);
device_lock(dev);
rc = __namespace_store(dev, attr, buf, len);
rc = nd_namespace_store(dev, &nd_btt->ndns, buf, len);
dev_dbg(dev, "%s: result: %zd wrote: %s%s", __func__,
rc, buf, buf[len - 1] == '\n' ? "" : "\n");
device_unlock(dev);
Expand Down Expand Up @@ -324,7 +185,7 @@ static struct device *__nd_btt_create(struct nd_region *nd_region,
dev->type = &nd_btt_device_type;
dev->groups = nd_btt_attribute_groups;
device_initialize(&nd_btt->dev);
if (ndns && !__nd_btt_attach_ndns(nd_btt, ndns)) {
if (ndns && !__nd_attach_ndns(&nd_btt->dev, ndns, &nd_btt->ndns)) {
dev_dbg(&ndns->dev, "%s failed, already claimed by %s\n",
__func__, dev_name(ndns->claim));
put_device(dev);
Expand Down Expand Up @@ -375,7 +236,7 @@ bool nd_btt_arena_is_valid(struct nd_btt *nd_btt, struct btt_sb *super)

checksum = le64_to_cpu(super->checksum);
super->checksum = 0;
if (checksum != nd_btt_sb_checksum(super))
if (checksum != nd_sb_checksum((struct nd_gen_sb *) super))
return false;
super->checksum = cpu_to_le64(checksum);

Expand All @@ -387,25 +248,6 @@ bool nd_btt_arena_is_valid(struct nd_btt *nd_btt, struct btt_sb *super)
}
EXPORT_SYMBOL(nd_btt_arena_is_valid);

/*
* nd_btt_sb_checksum: compute checksum for btt info block
*
* Returns a fletcher64 checksum of everything in the given info block
* except the last field (since that's where the checksum lives).
*/
u64 nd_btt_sb_checksum(struct btt_sb *btt_sb)
{
u64 sum;
__le64 sum_save;

sum_save = btt_sb->checksum;
btt_sb->checksum = 0;
sum = nd_fletcher64(btt_sb, sizeof(*btt_sb), 1);
btt_sb->checksum = sum_save;
return sum;
}
EXPORT_SYMBOL(nd_btt_sb_checksum);

static int __nd_btt_probe(struct nd_btt *nd_btt,
struct nd_namespace_common *ndns, struct btt_sb *btt_sb)
{
Expand Down Expand Up @@ -453,7 +295,9 @@ int nd_btt_probe(struct nd_namespace_common *ndns, void *drvdata)
dev_dbg(&ndns->dev, "%s: btt: %s\n", __func__,
rc == 0 ? dev_name(dev) : "<none>");
if (rc < 0) {
__nd_btt_detach_ndns(to_nd_btt(dev));
struct nd_btt *nd_btt = to_nd_btt(dev);

__nd_detach_ndns(dev, &nd_btt->ndns);
put_device(dev);
}

Expand Down
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