[PATCH 0/3] libnvdimm: export supported page size alignments

[PATCH 0/3] libnvdimm: export supported page size alignments

[Dan Williams]

This series is a minor rework of Oliver's original patch:
https://patchwork.kernel.org/patch/9811257/

It allows userspace to discover the system huge and gigantic page sizes
for aligning devices to support larger than PAGE_SIZE mappings for dax.

---

Dan Williams (2):
      libnvdimm: rename nd_sector_size_{show,store} to nd_size_select_{show,store}
      libnvdimm, pfn, dax: limit namespace alignments to the supported set

Oliver O'Halloran (1):
      libnvdimm, pfn, dax: show supported dax/pfn region alignments in sysfs


 drivers/nvdimm/btt_devs.c       |    4 ++--
 drivers/nvdimm/core.c           |   10 +++++----
 drivers/nvdimm/namespace_devs.c |    6 +++--
 drivers/nvdimm/nd.h             |    6 +++--
 drivers/nvdimm/pfn_devs.c       |   43 ++++++++++++++++++++++++---------------
 5 files changed, 39 insertions(+), 30 deletions(-)
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[PATCH 1/3] libnvdimm: rename nd_sector_size_{show, store} to nd_size_select_{show, store}

[Dan Williams]

Prepare for other another consumer of this size selection scheme that is
not a 'sector size'.

Cc: Oliver O'Halloran <oohall@gmail.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
 drivers/nvdimm/btt_devs.c       |    4 ++--
 drivers/nvdimm/core.c           |   10 +++++-----
 drivers/nvdimm/namespace_devs.c |    6 +++---
 drivers/nvdimm/nd.h             |    6 +++---
 4 files changed, 13 insertions(+), 13 deletions(-)

diff --git a/drivers/nvdimm/btt_devs.c b/drivers/nvdimm/btt_devs.c
index 3e359d282f8e..d58925295aa7 100644
--- a/drivers/nvdimm/btt_devs.c
+++ b/drivers/nvdimm/btt_devs.c
@@ -61,7 +61,7 @@ static ssize_t sector_size_show(struct device *dev,
 {
 	struct nd_btt *nd_btt = to_nd_btt(dev);
 
-	return nd_sector_size_show(nd_btt->lbasize, btt_lbasize_supported, buf);
+	return nd_size_select_show(nd_btt->lbasize, btt_lbasize_supported, buf);
 }
 
 static ssize_t sector_size_store(struct device *dev,
@@ -72,7 +72,7 @@ static ssize_t sector_size_store(struct device *dev,
 
 	device_lock(dev);
 	nvdimm_bus_lock(dev);
-	rc = nd_sector_size_store(dev, buf, &nd_btt->lbasize,
+	rc = nd_size_select_store(dev, buf, &nd_btt->lbasize,
 			btt_lbasize_supported);
 	dev_dbg(dev, "%s: result: %zd wrote: %s%s", __func__,
 			rc, buf, buf[len - 1] == '\n' ? "" : "\n");
diff --git a/drivers/nvdimm/core.c b/drivers/nvdimm/core.c
index 75bc08c6838c..bb71f0cf8f5d 100644
--- a/drivers/nvdimm/core.c
+++ b/drivers/nvdimm/core.c
@@ -277,14 +277,14 @@ int nd_uuid_store(struct device *dev, u8 **uuid_out, const char *buf,
 	return 0;
 }
 
-ssize_t nd_sector_size_show(unsigned long current_lbasize,
+ssize_t nd_size_select_show(unsigned long current_size,
 		const unsigned long *supported, char *buf)
 {
 	ssize_t len = 0;
 	int i;
 
 	for (i = 0; supported[i]; i++)
-		if (current_lbasize == supported[i])
+		if (current_size == supported[i])
 			len += sprintf(buf + len, "[%ld] ", supported[i]);
 		else
 			len += sprintf(buf + len, "%ld ", supported[i]);
@@ -292,8 +292,8 @@ ssize_t nd_sector_size_show(unsigned long current_lbasize,
 	return len;
 }
 
-ssize_t nd_sector_size_store(struct device *dev, const char *buf,
-		unsigned long *current_lbasize, const unsigned long *supported)
+ssize_t nd_size_select_store(struct device *dev, const char *buf,
+		unsigned long *current_size, const unsigned long *supported)
 {
 	unsigned long lbasize;
 	int rc, i;
@@ -310,7 +310,7 @@ ssize_t nd_sector_size_store(struct device *dev, const char *buf,
 			break;
 
 	if (supported[i]) {
-		*current_lbasize = lbasize;
+		*current_size = lbasize;
 		return 0;
 	} else {
 		return -EINVAL;
diff --git a/drivers/nvdimm/namespace_devs.c b/drivers/nvdimm/namespace_devs.c
index 5f1c6756e57c..1427a386a033 100644
--- a/drivers/nvdimm/namespace_devs.c
+++ b/drivers/nvdimm/namespace_devs.c
@@ -1313,14 +1313,14 @@ static ssize_t sector_size_show(struct device *dev,
 	if (is_namespace_blk(dev)) {
 		struct nd_namespace_blk *nsblk = to_nd_namespace_blk(dev);
 
-		return nd_sector_size_show(nsblk->lbasize,
+		return nd_size_select_show(nsblk->lbasize,
 				blk_lbasize_supported, buf);
 	}
 
 	if (is_namespace_pmem(dev)) {
 		struct nd_namespace_pmem *nspm = to_nd_namespace_pmem(dev);
 
-		return nd_sector_size_show(nspm->lbasize,
+		return nd_size_select_show(nspm->lbasize,
 				pmem_lbasize_supported, buf);
 	}
 	return -ENXIO;
@@ -1352,7 +1352,7 @@ static ssize_t sector_size_store(struct device *dev,
 	if (to_ndns(dev)->claim)
 		rc = -EBUSY;
 	if (rc >= 0)
-		rc = nd_sector_size_store(dev, buf, lbasize, supported);
+		rc = nd_size_select_store(dev, buf, lbasize, supported);
 	if (rc >= 0)
 		rc = nd_namespace_label_update(nd_region, dev);
 	dev_dbg(dev, "%s: result: %zd %s: %s%s", __func__,
diff --git a/drivers/nvdimm/nd.h b/drivers/nvdimm/nd.h
index a08fc2e24fb3..251c7e6d2588 100644
--- a/drivers/nvdimm/nd.h
+++ b/drivers/nvdimm/nd.h
@@ -234,10 +234,10 @@ void nd_device_unregister(struct device *dev, enum nd_async_mode mode);
 void nd_device_notify(struct device *dev, enum nvdimm_event event);
 int nd_uuid_store(struct device *dev, u8 **uuid_out, const char *buf,
 		size_t len);
-ssize_t nd_sector_size_show(unsigned long current_lbasize,
+ssize_t nd_size_select_show(unsigned long current_size,
 		const unsigned long *supported, char *buf);
-ssize_t nd_sector_size_store(struct device *dev, const char *buf,
-		unsigned long *current_lbasize, const unsigned long *supported);
+ssize_t nd_size_select_store(struct device *dev, const char *buf,
+		unsigned long *current_size, const unsigned long *supported);
 int __init nvdimm_init(void);
 int __init nd_region_init(void);
 int __init nd_label_init(void);

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[PATCH 2/3] libnvdimm, pfn, dax: show supported dax/pfn region alignments in sysfs

[Dan Williams]

From: Oliver O'Halloran <oohall@gmail.com>

The alignment of a DAX and PFN regions dictates the page sizes that can
be used to map the region. Even if the hardware page sizes are known the
actual range of supported page sizes that can be used with DAX depends
on the kernel configuration. As a result it's best that the kernel
advertises the alignments that should be used with these region types.

This patch adds the 'supported_alignments' region attribute to expose
this information to userspace.

Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
[djbw: integrate with nd_size_select_show() rename and other fixups]
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
 drivers/nvdimm/pfn_devs.c |   28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/drivers/nvdimm/pfn_devs.c b/drivers/nvdimm/pfn_devs.c
index 2ae9a000b090..610dd17a17f6 100644
--- a/drivers/nvdimm/pfn_devs.c
+++ b/drivers/nvdimm/pfn_devs.c
@@ -111,6 +111,26 @@ static ssize_t align_show(struct device *dev,
 	return sprintf(buf, "%ld\n", nd_pfn->align);
 }
 
+static const unsigned long *nd_pfn_supported_alignments(void)
+{
+	/*
+	 * This needs to be a local variable because the *_SIZE macros
+	 * aren't always constants.
+	 */
+	static const unsigned long supported_alignments[] = {
+		PAGE_SIZE,
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+		HPAGE_PMD_SIZE,
+#ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
+		HPAGE_PUD_SIZE,
+#endif
+#endif
+		0,
+	};
+
+	return supported_alignments;
+}
+
 static ssize_t __align_store(struct nd_pfn *nd_pfn, const char *buf)
 {
 	unsigned long val;
@@ -260,6 +280,13 @@ static ssize_t size_show(struct device *dev,
 }
 static DEVICE_ATTR_RO(size);
 
+static ssize_t supported_alignments_show(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	return nd_size_select_show(0, nd_pfn_supported_alignments(), buf);
+}
+static DEVICE_ATTR_RO(supported_alignments);
+
 static struct attribute *nd_pfn_attributes[] = {
 	&dev_attr_mode.attr,
 	&dev_attr_namespace.attr,
@@ -267,6 +294,7 @@ static struct attribute *nd_pfn_attributes[] = {
 	&dev_attr_align.attr,
 	&dev_attr_resource.attr,
 	&dev_attr_size.attr,
+	&dev_attr_supported_alignments.attr,
 	NULL,
 };
 

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[PATCH 3/3] libnvdimm, pfn, dax: limit namespace alignments to the supported set

[Dan Williams]

Now that we properly advertise the supported pte, pmd, and pud sizes,
restrict the supported alignments that can be set on a namespace. This
assumes that userspace was not previously relying on the ability to set
odd alignments. At least ndctl only ever supported setting the namespace
alignment to 4K, 2M, or 1G.

Cc: Oliver O'Halloran <oohall@gmail.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
 drivers/nvdimm/pfn_devs.c |   23 ++---------------------
 1 file changed, 2 insertions(+), 21 deletions(-)

diff --git a/drivers/nvdimm/pfn_devs.c b/drivers/nvdimm/pfn_devs.c
index 610dd17a17f6..f447a1eb919d 100644
--- a/drivers/nvdimm/pfn_devs.c
+++ b/drivers/nvdimm/pfn_devs.c
@@ -131,26 +131,6 @@ static const unsigned long *nd_pfn_supported_alignments(void)
 	return supported_alignments;
 }
 
-static ssize_t __align_store(struct nd_pfn *nd_pfn, const char *buf)
-{
-	unsigned long val;
-	int rc;
-
-	rc = kstrtoul(buf, 0, &val);
-	if (rc)
-		return rc;
-
-	if (!is_power_of_2(val) || val < PAGE_SIZE || val > SZ_1G)
-		return -EINVAL;
-
-	if (nd_pfn->dev.driver)
-		return -EBUSY;
-	else
-		nd_pfn->align = val;
-
-	return 0;
-}
-
 static ssize_t align_store(struct device *dev,
 		struct device_attribute *attr, const char *buf, size_t len)
 {
@@ -159,7 +139,8 @@ static ssize_t align_store(struct device *dev,
 
 	device_lock(dev);
 	nvdimm_bus_lock(dev);
-	rc = __align_store(nd_pfn, buf);
+	rc = nd_size_select_store(dev, buf, &nd_pfn->align,
+			nd_pfn_supported_alignments());
 	dev_dbg(dev, "%s: result: %zd wrote: %s%s", __func__,
 			rc, buf, buf[len - 1] == '\n' ? "" : "\n");
 	nvdimm_bus_unlock(dev);

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Re: [PATCH 2/3] libnvdimm, pfn, dax: show supported dax/pfn region alignments in sysfs

[kbuild test robot]

Hi Oliver,

[auto build test ERROR on linux-nvdimm/libnvdimm-for-next]
[also build test ERROR on v4.13-rc5 next-20170811]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Dan-Williams/libnvdimm-export-supported-page-size-alignments/20170815-105258
base:   https://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm.git libnvdimm-for-next
config: powerpc-allmodconfig (attached as .config)
compiler: powerpc64-linux-gnu-gcc (Debian 6.1.1-9) 6.1.1 20160705
reproduce:
        wget https://raw.githubusercontent.com/01org/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # save the attached .config to linux build tree
        make.cross ARCH=powerpc 

All error/warnings (new ones prefixed by >>):

   In file included from include/linux/mm.h:446:0,
                    from include/linux/memremap.h:3,
                    from drivers//nvdimm/pfn_devs.c:13:
   drivers//nvdimm/pfn_devs.c: In function 'nd_pfn_supported_alignments':
>> include/linux/huge_mm.h:83:24: error: initializer element is not constant
    #define HPAGE_PMD_SIZE ((1UL) << HPAGE_PMD_SHIFT)
                           ^
>> drivers//nvdimm/pfn_devs.c:123:3: note: in expansion of macro 'HPAGE_PMD_SIZE'
      HPAGE_PMD_SIZE,
      ^~~~~~~~~~~~~~
   include/linux/huge_mm.h:83:24: note: (near initialization for 'supported_alignments[1]')
    #define HPAGE_PMD_SIZE ((1UL) << HPAGE_PMD_SHIFT)
                           ^
>> drivers//nvdimm/pfn_devs.c:123:3: note: in expansion of macro 'HPAGE_PMD_SIZE'
      HPAGE_PMD_SIZE,
      ^~~~~~~~~~~~~~
--
   In file included from include/linux/mm.h:446:0,
                    from include/linux/memremap.h:3,
                    from drivers/nvdimm/pfn_devs.c:13:
   drivers/nvdimm/pfn_devs.c: In function 'nd_pfn_supported_alignments':
>> include/linux/huge_mm.h:83:24: error: initializer element is not constant
    #define HPAGE_PMD_SIZE ((1UL) << HPAGE_PMD_SHIFT)
                           ^
   drivers/nvdimm/pfn_devs.c:123:3: note: in expansion of macro 'HPAGE_PMD_SIZE'
      HPAGE_PMD_SIZE,
      ^~~~~~~~~~~~~~
   include/linux/huge_mm.h:83:24: note: (near initialization for 'supported_alignments[1]')
    #define HPAGE_PMD_SIZE ((1UL) << HPAGE_PMD_SHIFT)
                           ^
   drivers/nvdimm/pfn_devs.c:123:3: note: in expansion of macro 'HPAGE_PMD_SIZE'
      HPAGE_PMD_SIZE,
      ^~~~~~~~~~~~~~

vim +/HPAGE_PMD_SIZE +123 drivers//nvdimm/pfn_devs.c

  > 13	#include <linux/memremap.h>
    14	#include <linux/blkdev.h>
    15	#include <linux/device.h>
    16	#include <linux/genhd.h>
    17	#include <linux/sizes.h>
    18	#include <linux/slab.h>
    19	#include <linux/fs.h>
    20	#include <linux/mm.h>
    21	#include "nd-core.h"
    22	#include "pfn.h"
    23	#include "nd.h"
    24	
    25	static void nd_pfn_release(struct device *dev)
    26	{
    27		struct nd_region *nd_region = to_nd_region(dev->parent);
    28		struct nd_pfn *nd_pfn = to_nd_pfn(dev);
    29	
    30		dev_dbg(dev, "%s\n", __func__);
    31		nd_detach_ndns(&nd_pfn->dev, &nd_pfn->ndns);
    32		ida_simple_remove(&nd_region->pfn_ida, nd_pfn->id);
    33		kfree(nd_pfn->uuid);
    34		kfree(nd_pfn);
    35	}
    36	
    37	static struct device_type nd_pfn_device_type = {
    38		.name = "nd_pfn",
    39		.release = nd_pfn_release,
    40	};
    41	
    42	bool is_nd_pfn(struct device *dev)
    43	{
    44		return dev ? dev->type == &nd_pfn_device_type : false;
    45	}
    46	EXPORT_SYMBOL(is_nd_pfn);
    47	
    48	struct nd_pfn *to_nd_pfn(struct device *dev)
    49	{
    50		struct nd_pfn *nd_pfn = container_of(dev, struct nd_pfn, dev);
    51	
    52		WARN_ON(!is_nd_pfn(dev));
    53		return nd_pfn;
    54	}
    55	EXPORT_SYMBOL(to_nd_pfn);
    56	
    57	static ssize_t mode_show(struct device *dev,
    58			struct device_attribute *attr, char *buf)
    59	{
    60		struct nd_pfn *nd_pfn = to_nd_pfn_safe(dev);
    61	
    62		switch (nd_pfn->mode) {
    63		case PFN_MODE_RAM:
    64			return sprintf(buf, "ram\n");
    65		case PFN_MODE_PMEM:
    66			return sprintf(buf, "pmem\n");
    67		default:
    68			return sprintf(buf, "none\n");
    69		}
    70	}
    71	
    72	static ssize_t mode_store(struct device *dev,
    73			struct device_attribute *attr, const char *buf, size_t len)
    74	{
    75		struct nd_pfn *nd_pfn = to_nd_pfn_safe(dev);
    76		ssize_t rc = 0;
    77	
    78		device_lock(dev);
    79		nvdimm_bus_lock(dev);
    80		if (dev->driver)
    81			rc = -EBUSY;
    82		else {
    83			size_t n = len - 1;
    84	
    85			if (strncmp(buf, "pmem\n", n) == 0
    86					|| strncmp(buf, "pmem", n) == 0) {
    87				nd_pfn->mode = PFN_MODE_PMEM;
    88			} else if (strncmp(buf, "ram\n", n) == 0
    89					|| strncmp(buf, "ram", n) == 0)
    90				nd_pfn->mode = PFN_MODE_RAM;
    91			else if (strncmp(buf, "none\n", n) == 0
    92					|| strncmp(buf, "none", n) == 0)
    93				nd_pfn->mode = PFN_MODE_NONE;
    94			else
    95				rc = -EINVAL;
    96		}
    97		dev_dbg(dev, "%s: result: %zd wrote: %s%s", __func__,
    98				rc, buf, buf[len - 1] == '\n' ? "" : "\n");
    99		nvdimm_bus_unlock(dev);
   100		device_unlock(dev);
   101	
   102		return rc ? rc : len;
   103	}
   104	static DEVICE_ATTR_RW(mode);
   105	
   106	static ssize_t align_show(struct device *dev,
   107			struct device_attribute *attr, char *buf)
   108	{
   109		struct nd_pfn *nd_pfn = to_nd_pfn_safe(dev);
   110	
   111		return sprintf(buf, "%ld\n", nd_pfn->align);
   112	}
   113	
   114	static const unsigned long *nd_pfn_supported_alignments(void)
   115	{
   116		/*
   117		 * This needs to be a local variable because the *_SIZE macros
   118		 * aren't always constants.
   119		 */
   120		static const unsigned long supported_alignments[] = {
   121			PAGE_SIZE,
   122	#ifdef CONFIG_TRANSPARENT_HUGEPAGE
 > 123			HPAGE_PMD_SIZE,
   124	#ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
   125			HPAGE_PUD_SIZE,
   126	#endif
   127	#endif
   128			0,
   129		};
   130	
   131		return supported_alignments;
   132	}
   133	

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation
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Re: [PATCH 2/3] libnvdimm, pfn, dax: show supported dax/pfn region alignments in sysfs

[Oliver]

On Tue, Aug 15, 2017 at 4:02 PM, kbuild test robot <lkp@intel.com> wrote:
> Hi Oliver,
>
> [auto build test ERROR on linux-nvdimm/libnvdimm-for-next]
> [also build test ERROR on v4.13-rc5 next-20170811]
> [if your patch is applied to the wrong git tree, please drop us a note to help improve the system]
>
> url:    https://github.com/0day-ci/linux/commits/Dan-Williams/libnvdimm-export-supported-page-size-alignments/20170815-105258
> base:   https://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm.git libnvdimm-for-next
> config: powerpc-allmodconfig (attached as .config)
> compiler: powerpc64-linux-gnu-gcc (Debian 6.1.1-9) 6.1.1 20160705
> reproduce:
>         wget https://raw.githubusercontent.com/01org/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
>         chmod +x ~/bin/make.cross
>         # save the attached .config to linux build tree
>         make.cross ARCH=powerpc
>
> All error/warnings (new ones prefixed by >>):
>
>    In file included from include/linux/mm.h:446:0,
>                     from include/linux/memremap.h:3,
>                     from drivers//nvdimm/pfn_devs.c:13:
>    drivers//nvdimm/pfn_devs.c: In function 'nd_pfn_supported_alignments':
>>> include/linux/huge_mm.h:83:24: error: initializer element is not constant
>     #define HPAGE_PMD_SIZE ((1UL) << HPAGE_PMD_SHIFT)
>                            ^
>>> drivers//nvdimm/pfn_devs.c:123:3: note: in expansion of macro 'HPAGE_PMD_SIZE'
>       HPAGE_PMD_SIZE,
>       ^~~~~~~~~~~~~~
>    include/linux/huge_mm.h:83:24: note: (near initialization for 'supported_alignments[1]')
>     #define HPAGE_PMD_SIZE ((1UL) << HPAGE_PMD_SHIFT)
>                            ^
>>> drivers//nvdimm/pfn_devs.c:123:3: note: in expansion of macro 'HPAGE_PMD_SIZE'
>       HPAGE_PMD_SIZE,
>       ^~~~~~~~~~~~~~
> --
>    In file included from include/linux/mm.h:446:0,
>                     from include/linux/memremap.h:3,
>                     from drivers/nvdimm/pfn_devs.c:13:
>    drivers/nvdimm/pfn_devs.c: In function 'nd_pfn_supported_alignments':
>>> include/linux/huge_mm.h:83:24: error: initializer element is not constant
>     #define HPAGE_PMD_SIZE ((1UL) << HPAGE_PMD_SHIFT)
>                            ^
>    drivers/nvdimm/pfn_devs.c:123:3: note: in expansion of macro 'HPAGE_PMD_SIZE'
>       HPAGE_PMD_SIZE,
>       ^~~~~~~~~~~~~~
>    include/linux/huge_mm.h:83:24: note: (near initialization for 'supported_alignments[1]')
>     #define HPAGE_PMD_SIZE ((1UL) << HPAGE_PMD_SHIFT)
>                            ^
>    drivers/nvdimm/pfn_devs.c:123:3: note: in expansion of macro 'HPAGE_PMD_SIZE'
>       HPAGE_PMD_SIZE,
>       ^~~~~~~~~~~~~~
>
> vim +/HPAGE_PMD_SIZE +123 drivers//nvdimm/pfn_devs.c
>
>   > 13  #include <linux/memremap.h>
>     14  #include <linux/blkdev.h>
>     15  #include <linux/device.h>
>     16  #include <linux/genhd.h>
>     17  #include <linux/sizes.h>
>     18  #include <linux/slab.h>
>     19  #include <linux/fs.h>
>     20  #include <linux/mm.h>
>     21  #include "nd-core.h"
>     22  #include "pfn.h"
>     23  #include "nd.h"
>     24
>     25  static void nd_pfn_release(struct device *dev)
>     26  {
>     27          struct nd_region *nd_region = to_nd_region(dev->parent);
>     28          struct nd_pfn *nd_pfn = to_nd_pfn(dev);
>     29
>     30          dev_dbg(dev, "%s\n", __func__);
>     31          nd_detach_ndns(&nd_pfn->dev, &nd_pfn->ndns);
>     32          ida_simple_remove(&nd_region->pfn_ida, nd_pfn->id);
>     33          kfree(nd_pfn->uuid);
>     34          kfree(nd_pfn);
>     35  }
>     36
>     37  static struct device_type nd_pfn_device_type = {
>     38          .name = "nd_pfn",
>     39          .release = nd_pfn_release,
>     40  };
>     41
>     42  bool is_nd_pfn(struct device *dev)
>     43  {
>     44          return dev ? dev->type == &nd_pfn_device_type : false;
>     45  }
>     46  EXPORT_SYMBOL(is_nd_pfn);
>     47
>     48  struct nd_pfn *to_nd_pfn(struct device *dev)
>     49  {
>     50          struct nd_pfn *nd_pfn = container_of(dev, struct nd_pfn, dev);
>     51
>     52          WARN_ON(!is_nd_pfn(dev));
>     53          return nd_pfn;
>     54  }
>     55  EXPORT_SYMBOL(to_nd_pfn);
>     56
>     57  static ssize_t mode_show(struct device *dev,
>     58                  struct device_attribute *attr, char *buf)
>     59  {
>     60          struct nd_pfn *nd_pfn = to_nd_pfn_safe(dev);
>     61
>     62          switch (nd_pfn->mode) {
>     63          case PFN_MODE_RAM:
>     64                  return sprintf(buf, "ram\n");
>     65          case PFN_MODE_PMEM:
>     66                  return sprintf(buf, "pmem\n");
>     67          default:
>     68                  return sprintf(buf, "none\n");
>     69          }
>     70  }
>     71
>     72  static ssize_t mode_store(struct device *dev,
>     73                  struct device_attribute *attr, const char *buf, size_t len)
>     74  {
>     75          struct nd_pfn *nd_pfn = to_nd_pfn_safe(dev);
>     76          ssize_t rc = 0;
>     77
>     78          device_lock(dev);
>     79          nvdimm_bus_lock(dev);
>     80          if (dev->driver)
>     81                  rc = -EBUSY;
>     82          else {
>     83                  size_t n = len - 1;
>     84
>     85                  if (strncmp(buf, "pmem\n", n) == 0
>     86                                  || strncmp(buf, "pmem", n) == 0) {
>     87                          nd_pfn->mode = PFN_MODE_PMEM;
>     88                  } else if (strncmp(buf, "ram\n", n) == 0
>     89                                  || strncmp(buf, "ram", n) == 0)
>     90                          nd_pfn->mode = PFN_MODE_RAM;
>     91                  else if (strncmp(buf, "none\n", n) == 0
>     92                                  || strncmp(buf, "none", n) == 0)
>     93                          nd_pfn->mode = PFN_MODE_NONE;
>     94                  else
>     95                          rc = -EINVAL;
>     96          }
>     97          dev_dbg(dev, "%s: result: %zd wrote: %s%s", __func__,
>     98                          rc, buf, buf[len - 1] == '\n' ? "" : "\n");
>     99          nvdimm_bus_unlock(dev);
>    100          device_unlock(dev);
>    101
>    102          return rc ? rc : len;
>    103  }
>    104  static DEVICE_ATTR_RW(mode);
>    105
>    106  static ssize_t align_show(struct device *dev,
>    107                  struct device_attribute *attr, char *buf)
>    108  {
>    109          struct nd_pfn *nd_pfn = to_nd_pfn_safe(dev);
>    110
>    111          return sprintf(buf, "%ld\n", nd_pfn->align);
>    112  }
>    113
>    114  static const unsigned long *nd_pfn_supported_alignments(void)
>    115  {
>    116          /*
>    117           * This needs to be a local variable because the *_SIZE macros
>    118           * aren't always constants.
>    119           */

I probably should have been clearer, "local" here really means
"non-static". Otherwise the array could have been made a global.

>    120          static const unsigned long supported_alignments[] = {
>    121                  PAGE_SIZE,
>    122  #ifdef CONFIG_TRANSPARENT_HUGEPAGE
>  > 123                  HPAGE_PMD_SIZE,
>    124  #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
>    125                  HPAGE_PUD_SIZE,
>    126  #endif
>    127  #endif
>    128                  0,
>    129          };
>    130
>    131          return supported_alignments;
>    132  }
>    133
>
> ---
> 0-DAY kernel test infrastructure                Open Source Technology Center
> https://lists.01.org/pipermail/kbuild-all                   Intel Corporation
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Re: [PATCH 2/3] libnvdimm, pfn, dax: show supported dax/pfn region alignments in sysfs

[Dan Williams]

On Mon, Aug 14, 2017 at 11:46 PM, Oliver <oohall@gmail.com> wrote:
> On Tue, Aug 15, 2017 at 4:02 PM, kbuild test robot <lkp@intel.com> wrote:
[..]
>>    114  static const unsigned long *nd_pfn_supported_alignments(void)
>>    115  {
>>    116          /*
>>    117           * This needs to be a local variable because the *_SIZE macros
>>    118           * aren't always constants.
>>    119           */
>
> I probably should have been clearer, "local" here really means
> "non-static". Otherwise the array could have been made a global.
>

Whoops, my fault. How about this:

@@ -127,8 +127,11 @@ static const unsigned long
*nd_pfn_supported_alignments(void)
 #endif
                0,
        };
+       static unsigned long data[ARRAY_SIZE(supported_alignments)];

-       return supported_alignments;
+       memcpy(data, supported_alignments, sizeof(data));
+
+       return data;
 }
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Re: [PATCH 2/3] libnvdimm, pfn, dax: show supported dax/pfn region alignments in sysfs

[Oliver]

On Wed, Aug 16, 2017 at 1:47 AM, Dan Williams <dan.j.williams@intel.com> wrote:
> On Mon, Aug 14, 2017 at 11:46 PM, Oliver <oohall@gmail.com> wrote:
>> On Tue, Aug 15, 2017 at 4:02 PM, kbuild test robot <lkp@intel.com> wrote:
> [..]
>>>    114  static const unsigned long *nd_pfn_supported_alignments(void)
>>>    115  {
>>>    116          /*
>>>    117           * This needs to be a local variable because the *_SIZE macros
>>>    118           * aren't always constants.
>>>    119           */
>>
>> I probably should have been clearer, "local" here really means
>> "non-static". Otherwise the array could have been made a global.
>>
>
> Whoops, my fault. How about this:
>
> @@ -127,8 +127,11 @@ static const unsigned long
> *nd_pfn_supported_alignments(void)
>  #endif
>                 0,
>         };
> +       static unsigned long data[ARRAY_SIZE(supported_alignments)];
>
> -       return supported_alignments;
> +       memcpy(data, supported_alignments, sizeof(data));
> +
> +       return data;
>  }

That should do the trick, but you'll need to fix up the source array
declaration too.
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