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authorLinus Torvalds <torvalds@linux-foundation.org>2018-10-25 06:31:56 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2018-10-25 06:31:56 -0700
commit6078e07dcf5348075713124508d03786dc9ffa8b (patch)
tree0a93be6dc3de629352ea269a7b99018ab40b35e0 /drivers/nvdimm
parentdf132e4062afe06ddc9938802243d704906a884a (diff)
parent594861215c834e4b59a30d4b794f6372717bc197 (diff)
downloadlinux-6078e07dcf5348075713124508d03786dc9ffa8b.tar.bz2
Merge tag 'libnvdimm-for-4.20' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm
Pull libnvdimm updates from Dan Williams: - Improve the efficiency and performance of reading nvdimm-namespace labels. Reduce the amount of label data read at driver load time by a few orders of magnitude. Reduce heavyweight call-outs to platform-firmware routines. - Handle media errors located in the 'struct page' array stored on a persistent memory namespace. Let the kernel clear these errors rather than an awkward userspace workaround. - Fix Address Range Scrub (ARS) completion tracking. Correct occasions where the kernel indicates completion of ARS before submission. - Fix asynchronous device registration reference counting. - Add support for reporting an nvdimm dirty-shutdown-count via sysfs. - Fix various small libnvdimm core and uapi issues. * tag 'libnvdimm-for-4.20' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm: (21 commits) acpi, nfit: Further restrict userspace ARS start requests acpi, nfit: Fix Address Range Scrub completion tracking UAPI: ndctl: Remove use of PAGE_SIZE UAPI: ndctl: Fix g++-unsupported initialisation in headers tools/testing/nvdimm: Populate dirty shutdown data acpi, nfit: Collect shutdown status acpi, nfit: Introduce nfit_mem flags libnvdimm, label: Fix sparse warning nvdimm: Use namespace index data to reduce number of label reads needed nvdimm: Split label init out from the logic for getting config data nvdimm: Remove empty if statement nvdimm: Clarify comment in sizeof_namespace_index nvdimm: Sanity check labeloff libnvdimm, dimm: Maximize label transfer size libnvdimm, pmem: Fix badblocks population for 'raw' namespaces libnvdimm, namespace: Drop the repeat assignment for variable dev->parent libnvdimm, region: Fail badblocks listing for inactive regions libnvdimm, pfn: during init, clear errors in the metadata area libnvdimm: Set device node in nd_device_register libnvdimm: Hold reference on parent while scheduling async init ...
Diffstat (limited to 'drivers/nvdimm')
-rw-r--r--drivers/nvdimm/bus.c20
-rw-r--r--drivers/nvdimm/dimm.c6
-rw-r--r--drivers/nvdimm/dimm_devs.c60
-rw-r--r--drivers/nvdimm/label.c144
-rw-r--r--drivers/nvdimm/label.h4
-rw-r--r--drivers/nvdimm/namespace_devs.c1
-rw-r--r--drivers/nvdimm/nd-core.h1
-rw-r--r--drivers/nvdimm/nd.h2
-rw-r--r--drivers/nvdimm/pfn_devs.c61
-rw-r--r--drivers/nvdimm/pmem.c4
-rw-r--r--drivers/nvdimm/region_devs.c11
11 files changed, 251 insertions, 63 deletions
diff --git a/drivers/nvdimm/bus.c b/drivers/nvdimm/bus.c
index 8aae6dcc839f..f1fb39921236 100644
--- a/drivers/nvdimm/bus.c
+++ b/drivers/nvdimm/bus.c
@@ -54,12 +54,6 @@ static int to_nd_device_type(struct device *dev)
static int nvdimm_bus_uevent(struct device *dev, struct kobj_uevent_env *env)
{
- /*
- * Ensure that region devices always have their numa node set as
- * early as possible.
- */
- if (is_nd_region(dev))
- set_dev_node(dev, to_nd_region(dev)->numa_node);
return add_uevent_var(env, "MODALIAS=" ND_DEVICE_MODALIAS_FMT,
to_nd_device_type(dev));
}
@@ -488,6 +482,8 @@ static void nd_async_device_register(void *d, async_cookie_t cookie)
put_device(dev);
}
put_device(dev);
+ if (dev->parent)
+ put_device(dev->parent);
}
static void nd_async_device_unregister(void *d, async_cookie_t cookie)
@@ -506,7 +502,19 @@ void __nd_device_register(struct device *dev)
{
if (!dev)
return;
+
+ /*
+ * Ensure that region devices always have their NUMA node set as
+ * early as possible. This way we are able to make certain that
+ * any memory associated with the creation and the creation
+ * itself of the region is associated with the correct node.
+ */
+ if (is_nd_region(dev))
+ set_dev_node(dev, to_nd_region(dev)->numa_node);
+
dev->bus = &nvdimm_bus_type;
+ if (dev->parent)
+ get_device(dev->parent);
get_device(dev);
async_schedule_domain(nd_async_device_register, dev,
&nd_async_domain);
diff --git a/drivers/nvdimm/dimm.c b/drivers/nvdimm/dimm.c
index 6c8fb7590838..9899c97138a3 100644
--- a/drivers/nvdimm/dimm.c
+++ b/drivers/nvdimm/dimm.c
@@ -75,7 +75,7 @@ static int nvdimm_probe(struct device *dev)
* DIMM capacity. We fail the dimm probe to prevent regions from
* attempting to parse the label area.
*/
- rc = nvdimm_init_config_data(ndd);
+ rc = nd_label_data_init(ndd);
if (rc == -EACCES)
nvdimm_set_locked(dev);
if (rc)
@@ -84,10 +84,6 @@ static int nvdimm_probe(struct device *dev)
dev_dbg(dev, "config data size: %d\n", ndd->nsarea.config_size);
nvdimm_bus_lock(dev);
- ndd->ns_current = nd_label_validate(ndd);
- ndd->ns_next = nd_label_next_nsindex(ndd->ns_current);
- nd_label_copy(ndd, to_next_namespace_index(ndd),
- to_current_namespace_index(ndd));
if (ndd->ns_current >= 0) {
rc = nd_label_reserve_dpa(ndd);
if (rc == 0)
diff --git a/drivers/nvdimm/dimm_devs.c b/drivers/nvdimm/dimm_devs.c
index 863cabc35215..6c3de2317390 100644
--- a/drivers/nvdimm/dimm_devs.c
+++ b/drivers/nvdimm/dimm_devs.c
@@ -85,56 +85,48 @@ int nvdimm_init_nsarea(struct nvdimm_drvdata *ndd)
return cmd_rc;
}
-int nvdimm_init_config_data(struct nvdimm_drvdata *ndd)
+int nvdimm_get_config_data(struct nvdimm_drvdata *ndd, void *buf,
+ size_t offset, size_t len)
{
struct nvdimm_bus *nvdimm_bus = walk_to_nvdimm_bus(ndd->dev);
+ struct nvdimm_bus_descriptor *nd_desc = nvdimm_bus->nd_desc;
int rc = validate_dimm(ndd), cmd_rc = 0;
struct nd_cmd_get_config_data_hdr *cmd;
- struct nvdimm_bus_descriptor *nd_desc;
- u32 max_cmd_size, config_size;
- size_t offset;
+ size_t max_cmd_size, buf_offset;
if (rc)
return rc;
- if (ndd->data)
- return 0;
-
- if (ndd->nsarea.status || ndd->nsarea.max_xfer == 0
- || ndd->nsarea.config_size < ND_LABEL_MIN_SIZE) {
- dev_dbg(ndd->dev, "failed to init config data area: (%d:%d)\n",
- ndd->nsarea.max_xfer, ndd->nsarea.config_size);
+ if (offset + len > ndd->nsarea.config_size)
return -ENXIO;
- }
- ndd->data = kvmalloc(ndd->nsarea.config_size, GFP_KERNEL);
- if (!ndd->data)
- return -ENOMEM;
-
- max_cmd_size = min_t(u32, PAGE_SIZE, ndd->nsarea.max_xfer);
- cmd = kzalloc(max_cmd_size + sizeof(*cmd), GFP_KERNEL);
+ max_cmd_size = min_t(u32, len, ndd->nsarea.max_xfer);
+ cmd = kvzalloc(max_cmd_size + sizeof(*cmd), GFP_KERNEL);
if (!cmd)
return -ENOMEM;
- nd_desc = nvdimm_bus->nd_desc;
- for (config_size = ndd->nsarea.config_size, offset = 0;
- config_size; config_size -= cmd->in_length,
- offset += cmd->in_length) {
- cmd->in_length = min(config_size, max_cmd_size);
- cmd->in_offset = offset;
+ for (buf_offset = 0; len;
+ len -= cmd->in_length, buf_offset += cmd->in_length) {
+ size_t cmd_size;
+
+ cmd->in_offset = offset + buf_offset;
+ cmd->in_length = min(max_cmd_size, len);
+
+ cmd_size = sizeof(*cmd) + cmd->in_length;
+
rc = nd_desc->ndctl(nd_desc, to_nvdimm(ndd->dev),
- ND_CMD_GET_CONFIG_DATA, cmd,
- cmd->in_length + sizeof(*cmd), &cmd_rc);
+ ND_CMD_GET_CONFIG_DATA, cmd, cmd_size, &cmd_rc);
if (rc < 0)
break;
if (cmd_rc < 0) {
rc = cmd_rc;
break;
}
- memcpy(ndd->data + offset, cmd->out_buf, cmd->in_length);
+
+ /* out_buf should be valid, copy it into our output buffer */
+ memcpy(buf + buf_offset, cmd->out_buf, cmd->in_length);
}
- dev_dbg(ndd->dev, "len: %zu rc: %d\n", offset, rc);
- kfree(cmd);
+ kvfree(cmd);
return rc;
}
@@ -151,15 +143,11 @@ int nvdimm_set_config_data(struct nvdimm_drvdata *ndd, size_t offset,
if (rc)
return rc;
- if (!ndd->data)
- return -ENXIO;
-
if (offset + len > ndd->nsarea.config_size)
return -ENXIO;
- max_cmd_size = min_t(u32, PAGE_SIZE, len);
- max_cmd_size = min_t(u32, max_cmd_size, ndd->nsarea.max_xfer);
- cmd = kzalloc(max_cmd_size + sizeof(*cmd) + sizeof(u32), GFP_KERNEL);
+ max_cmd_size = min_t(u32, len, ndd->nsarea.max_xfer);
+ cmd = kvzalloc(max_cmd_size + sizeof(*cmd) + sizeof(u32), GFP_KERNEL);
if (!cmd)
return -ENOMEM;
@@ -183,7 +171,7 @@ int nvdimm_set_config_data(struct nvdimm_drvdata *ndd, size_t offset,
break;
}
}
- kfree(cmd);
+ kvfree(cmd);
return rc;
}
diff --git a/drivers/nvdimm/label.c b/drivers/nvdimm/label.c
index 1d28cd656536..750dbaa6ce82 100644
--- a/drivers/nvdimm/label.c
+++ b/drivers/nvdimm/label.c
@@ -75,7 +75,8 @@ size_t sizeof_namespace_index(struct nvdimm_drvdata *ndd)
/*
* Per UEFI 2.7, the minimum size of the Label Storage Area is large
* enough to hold 2 index blocks and 2 labels. The minimum index
- * block size is 256 bytes, and the minimum label size is 256 bytes.
+ * block size is 256 bytes. The label size is 128 for namespaces
+ * prior to version 1.2 and at minimum 256 for version 1.2 and later.
*/
nslot = nvdimm_num_label_slots(ndd);
space = ndd->nsarea.config_size - nslot * sizeof_namespace_label(ndd);
@@ -183,6 +184,13 @@ static int __nd_label_validate(struct nvdimm_drvdata *ndd)
__le64_to_cpu(nsindex[i]->otheroff));
continue;
}
+ if (__le64_to_cpu(nsindex[i]->labeloff)
+ != 2 * sizeof_namespace_index(ndd)) {
+ dev_dbg(dev, "nsindex%d labeloff: %#llx invalid\n",
+ i, (unsigned long long)
+ __le64_to_cpu(nsindex[i]->labeloff));
+ continue;
+ }
size = __le64_to_cpu(nsindex[i]->mysize);
if (size > sizeof_namespace_index(ndd)
@@ -227,7 +235,7 @@ static int __nd_label_validate(struct nvdimm_drvdata *ndd)
return -1;
}
-int nd_label_validate(struct nvdimm_drvdata *ndd)
+static int nd_label_validate(struct nvdimm_drvdata *ndd)
{
/*
* In order to probe for and validate namespace index blocks we
@@ -250,12 +258,12 @@ int nd_label_validate(struct nvdimm_drvdata *ndd)
return -1;
}
-void nd_label_copy(struct nvdimm_drvdata *ndd, struct nd_namespace_index *dst,
- struct nd_namespace_index *src)
+static void nd_label_copy(struct nvdimm_drvdata *ndd,
+ struct nd_namespace_index *dst,
+ struct nd_namespace_index *src)
{
- if (dst && src)
- /* pass */;
- else
+ /* just exit if either destination or source is NULL */
+ if (!dst || !src)
return;
memcpy(dst, src, sizeof_namespace_index(ndd));
@@ -410,6 +418,128 @@ int nd_label_reserve_dpa(struct nvdimm_drvdata *ndd)
return 0;
}
+int nd_label_data_init(struct nvdimm_drvdata *ndd)
+{
+ size_t config_size, read_size, max_xfer, offset;
+ struct nd_namespace_index *nsindex;
+ unsigned int i;
+ int rc = 0;
+ u32 nslot;
+
+ if (ndd->data)
+ return 0;
+
+ if (ndd->nsarea.status || ndd->nsarea.max_xfer == 0) {
+ dev_dbg(ndd->dev, "failed to init config data area: (%u:%u)\n",
+ ndd->nsarea.max_xfer, ndd->nsarea.config_size);
+ return -ENXIO;
+ }
+
+ /*
+ * We need to determine the maximum index area as this is the section
+ * we must read and validate before we can start processing labels.
+ *
+ * If the area is too small to contain the two indexes and 2 labels
+ * then we abort.
+ *
+ * Start at a label size of 128 as this should result in the largest
+ * possible namespace index size.
+ */
+ ndd->nslabel_size = 128;
+ read_size = sizeof_namespace_index(ndd) * 2;
+ if (!read_size)
+ return -ENXIO;
+
+ /* Allocate config data */
+ config_size = ndd->nsarea.config_size;
+ ndd->data = kvzalloc(config_size, GFP_KERNEL);
+ if (!ndd->data)
+ return -ENOMEM;
+
+ /*
+ * We want to guarantee as few reads as possible while conserving
+ * memory. To do that we figure out how much unused space will be left
+ * in the last read, divide that by the total number of reads it is
+ * going to take given our maximum transfer size, and then reduce our
+ * maximum transfer size based on that result.
+ */
+ max_xfer = min_t(size_t, ndd->nsarea.max_xfer, config_size);
+ if (read_size < max_xfer) {
+ /* trim waste */
+ max_xfer -= ((max_xfer - 1) - (config_size - 1) % max_xfer) /
+ DIV_ROUND_UP(config_size, max_xfer);
+ /* make certain we read indexes in exactly 1 read */
+ if (max_xfer < read_size)
+ max_xfer = read_size;
+ }
+
+ /* Make our initial read size a multiple of max_xfer size */
+ read_size = min(DIV_ROUND_UP(read_size, max_xfer) * max_xfer,
+ config_size);
+
+ /* Read the index data */
+ rc = nvdimm_get_config_data(ndd, ndd->data, 0, read_size);
+ if (rc)
+ goto out_err;
+
+ /* Validate index data, if not valid assume all labels are invalid */
+ ndd->ns_current = nd_label_validate(ndd);
+ if (ndd->ns_current < 0)
+ return 0;
+
+ /* Record our index values */
+ ndd->ns_next = nd_label_next_nsindex(ndd->ns_current);
+
+ /* Copy "current" index on top of the "next" index */
+ nsindex = to_current_namespace_index(ndd);
+ nd_label_copy(ndd, to_next_namespace_index(ndd), nsindex);
+
+ /* Determine starting offset for label data */
+ offset = __le64_to_cpu(nsindex->labeloff);
+ nslot = __le32_to_cpu(nsindex->nslot);
+
+ /* Loop through the free list pulling in any active labels */
+ for (i = 0; i < nslot; i++, offset += ndd->nslabel_size) {
+ size_t label_read_size;
+
+ /* zero out the unused labels */
+ if (test_bit_le(i, nsindex->free)) {
+ memset(ndd->data + offset, 0, ndd->nslabel_size);
+ continue;
+ }
+
+ /* if we already read past here then just continue */
+ if (offset + ndd->nslabel_size <= read_size)
+ continue;
+
+ /* if we haven't read in a while reset our read_size offset */
+ if (read_size < offset)
+ read_size = offset;
+
+ /* determine how much more will be read after this next call. */
+ label_read_size = offset + ndd->nslabel_size - read_size;
+ label_read_size = DIV_ROUND_UP(label_read_size, max_xfer) *
+ max_xfer;
+
+ /* truncate last read if needed */
+ if (read_size + label_read_size > config_size)
+ label_read_size = config_size - read_size;
+
+ /* Read the label data */
+ rc = nvdimm_get_config_data(ndd, ndd->data + read_size,
+ read_size, label_read_size);
+ if (rc)
+ goto out_err;
+
+ /* push read_size to next read offset */
+ read_size += label_read_size;
+ }
+
+ dev_dbg(ndd->dev, "len: %zu rc: %d\n", offset, rc);
+out_err:
+ return rc;
+}
+
int nd_label_active_count(struct nvdimm_drvdata *ndd)
{
struct nd_namespace_index *nsindex;
diff --git a/drivers/nvdimm/label.h b/drivers/nvdimm/label.h
index 18bbe183b3a9..e9a2ad3c2150 100644
--- a/drivers/nvdimm/label.h
+++ b/drivers/nvdimm/label.h
@@ -138,9 +138,7 @@ static inline int nd_label_next_nsindex(int index)
}
struct nvdimm_drvdata;
-int nd_label_validate(struct nvdimm_drvdata *ndd);
-void nd_label_copy(struct nvdimm_drvdata *ndd, struct nd_namespace_index *dst,
- struct nd_namespace_index *src);
+int nd_label_data_init(struct nvdimm_drvdata *ndd);
size_t sizeof_namespace_index(struct nvdimm_drvdata *ndd);
int nd_label_active_count(struct nvdimm_drvdata *ndd);
struct nd_namespace_label *nd_label_active(struct nvdimm_drvdata *ndd, int n);
diff --git a/drivers/nvdimm/namespace_devs.c b/drivers/nvdimm/namespace_devs.c
index 4a4266250c28..681af3a8fd62 100644
--- a/drivers/nvdimm/namespace_devs.c
+++ b/drivers/nvdimm/namespace_devs.c
@@ -2099,7 +2099,6 @@ static struct device *nd_namespace_pmem_create(struct nd_region *nd_region)
return NULL;
}
dev_set_name(dev, "namespace%d.%d", nd_region->id, nspm->id);
- dev->parent = &nd_region->dev;
dev->groups = nd_namespace_attribute_groups;
nd_namespace_pmem_set_resource(nd_region, nspm, 0);
diff --git a/drivers/nvdimm/nd-core.h b/drivers/nvdimm/nd-core.h
index ac68072fb8cd..182258f64417 100644
--- a/drivers/nvdimm/nd-core.h
+++ b/drivers/nvdimm/nd-core.h
@@ -14,7 +14,6 @@
#define __ND_CORE_H__
#include <linux/libnvdimm.h>
#include <linux/device.h>
-#include <linux/libnvdimm.h>
#include <linux/sizes.h>
#include <linux/mutex.h>
#include <linux/nd.h>
diff --git a/drivers/nvdimm/nd.h b/drivers/nvdimm/nd.h
index 98317e7ce5b5..e79cc8e5c114 100644
--- a/drivers/nvdimm/nd.h
+++ b/drivers/nvdimm/nd.h
@@ -241,6 +241,8 @@ struct nvdimm_drvdata *to_ndd(struct nd_mapping *nd_mapping);
int nvdimm_check_config_data(struct device *dev);
int nvdimm_init_nsarea(struct nvdimm_drvdata *ndd);
int nvdimm_init_config_data(struct nvdimm_drvdata *ndd);
+int nvdimm_get_config_data(struct nvdimm_drvdata *ndd, void *buf,
+ size_t offset, size_t len);
int nvdimm_set_config_data(struct nvdimm_drvdata *ndd, size_t offset,
void *buf, size_t len);
long nvdimm_clear_poison(struct device *dev, phys_addr_t phys,
diff --git a/drivers/nvdimm/pfn_devs.c b/drivers/nvdimm/pfn_devs.c
index 3f7ad5bc443e..24c64090169e 100644
--- a/drivers/nvdimm/pfn_devs.c
+++ b/drivers/nvdimm/pfn_devs.c
@@ -361,6 +361,65 @@ struct device *nd_pfn_create(struct nd_region *nd_region)
return dev;
}
+/*
+ * nd_pfn_clear_memmap_errors() clears any errors in the volatile memmap
+ * space associated with the namespace. If the memmap is set to DRAM, then
+ * this is a no-op. Since the memmap area is freshly initialized during
+ * probe, we have an opportunity to clear any badblocks in this area.
+ */
+static int nd_pfn_clear_memmap_errors(struct nd_pfn *nd_pfn)
+{
+ struct nd_region *nd_region = to_nd_region(nd_pfn->dev.parent);
+ struct nd_namespace_common *ndns = nd_pfn->ndns;
+ void *zero_page = page_address(ZERO_PAGE(0));
+ struct nd_pfn_sb *pfn_sb = nd_pfn->pfn_sb;
+ int num_bad, meta_num, rc, bb_present;
+ sector_t first_bad, meta_start;
+ struct nd_namespace_io *nsio;
+
+ if (nd_pfn->mode != PFN_MODE_PMEM)
+ return 0;
+
+ nsio = to_nd_namespace_io(&ndns->dev);
+ meta_start = (SZ_4K + sizeof(*pfn_sb)) >> 9;
+ meta_num = (le64_to_cpu(pfn_sb->dataoff) >> 9) - meta_start;
+
+ do {
+ unsigned long zero_len;
+ u64 nsoff;
+
+ bb_present = badblocks_check(&nd_region->bb, meta_start,
+ meta_num, &first_bad, &num_bad);
+ if (bb_present) {
+ dev_dbg(&nd_pfn->dev, "meta: %x badblocks at %lx\n",
+ num_bad, first_bad);
+ nsoff = ALIGN_DOWN((nd_region->ndr_start
+ + (first_bad << 9)) - nsio->res.start,
+ PAGE_SIZE);
+ zero_len = ALIGN(num_bad << 9, PAGE_SIZE);
+ while (zero_len) {
+ unsigned long chunk = min(zero_len, PAGE_SIZE);
+
+ rc = nvdimm_write_bytes(ndns, nsoff, zero_page,
+ chunk, 0);
+ if (rc)
+ break;
+
+ zero_len -= chunk;
+ nsoff += chunk;
+ }
+ if (rc) {
+ dev_err(&nd_pfn->dev,
+ "error clearing %x badblocks at %lx\n",
+ num_bad, first_bad);
+ return rc;
+ }
+ }
+ } while (bb_present);
+
+ return 0;
+}
+
int nd_pfn_validate(struct nd_pfn *nd_pfn, const char *sig)
{
u64 checksum, offset;
@@ -477,7 +536,7 @@ int nd_pfn_validate(struct nd_pfn *nd_pfn, const char *sig)
return -ENXIO;
}
- return 0;
+ return nd_pfn_clear_memmap_errors(nd_pfn);
}
EXPORT_SYMBOL(nd_pfn_validate);
diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
index a75d10c23d80..0e39e3d1846f 100644
--- a/drivers/nvdimm/pmem.c
+++ b/drivers/nvdimm/pmem.c
@@ -421,9 +421,11 @@ static int pmem_attach_disk(struct device *dev,
addr = devm_memremap_pages(dev, &pmem->pgmap);
pmem->pfn_flags |= PFN_MAP;
memcpy(&bb_res, &pmem->pgmap.res, sizeof(bb_res));
- } else
+ } else {
addr = devm_memremap(dev, pmem->phys_addr,
pmem->size, ARCH_MEMREMAP_PMEM);
+ memcpy(&bb_res, &nsio->res, sizeof(bb_res));
+ }
/*
* At release time the queue must be frozen before
diff --git a/drivers/nvdimm/region_devs.c b/drivers/nvdimm/region_devs.c
index fa37afcd43ff..174a418cb171 100644
--- a/drivers/nvdimm/region_devs.c
+++ b/drivers/nvdimm/region_devs.c
@@ -560,10 +560,17 @@ static ssize_t region_badblocks_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct nd_region *nd_region = to_nd_region(dev);
+ ssize_t rc;
- return badblocks_show(&nd_region->bb, buf, 0);
-}
+ device_lock(dev);
+ if (dev->driver)
+ rc = badblocks_show(&nd_region->bb, buf, 0);
+ else
+ rc = -ENXIO;
+ device_unlock(dev);
+ return rc;
+}
static DEVICE_ATTR(badblocks, 0444, region_badblocks_show, NULL);
static ssize_t resource_show(struct device *dev,