Date:	Thu, 24 Mar 2016 15:36:58 +0100
From:	Johannes Thumshirn <jthumshirn@...e.de>
To:	linux-nvdimm@...ts.01.org
Cc:	Dan Williams <dan.j.williams@...el.com>,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 12/13] libnvdimm, pmem, pfn: move pfn setup to the core

On Mittwoch, 23. März 2016 18:26:24 CET Dan Williams wrote:
> Now that pmem internals have been disentangled from pfn setup, that code
> can move to the core.  This is in preparation for adding another user of
> the pfn-device capabilities.
> 
> Signed-off-by: Dan Williams <dan.j.williams@...el.com>
> ---
>  drivers/nvdimm/nd.h       |    7 ++
>  drivers/nvdimm/pfn_devs.c |  183
> +++++++++++++++++++++++++++++++++++++++++++++ drivers/nvdimm/pmem.c     | 
> 184 --------------------------------------------- 3 files changed, 190
> insertions(+), 184 deletions(-)
> 
> diff --git a/drivers/nvdimm/nd.h b/drivers/nvdimm/nd.h
> index a42c823c0a67..8e563c4a3e8c 100644
> --- a/drivers/nvdimm/nd.h
> +++ b/drivers/nvdimm/nd.h
> @@ -272,9 +272,16 @@ const char *nvdimm_namespace_disk_name(struct
> nd_namespace_common *ndns, void nvdimm_badblocks_populate(struct nd_region
> *nd_region,
>  		struct badblocks *bb, const struct resource *res);
>  #if IS_ENABLED(CONFIG_ND_CLAIM)
> +struct vmem_altmap *nvdimm_setup_pfn(struct nd_pfn *nd_pfn,
> +		struct resource *res, struct vmem_altmap *altmap);
>  int devm_nsio_enable(struct device *dev, struct nd_namespace_io *nsio);
>  void devm_nsio_disable(struct device *dev, struct nd_namespace_io *nsio);
>  #else
> +static inline struct vmem_altmap *nvdimm_setup_pfn(struct nd_pfn *nd_pfn,
> +		struct resource *res, struct vmem_altmap *altmap)
> +{
> +	return ERR_PTR(-ENXIO);
> +}
>  static inline int devm_nsio_enable(struct device *dev,
>  		struct nd_namespace_io *nsio)
>  {
> diff --git a/drivers/nvdimm/pfn_devs.c b/drivers/nvdimm/pfn_devs.c
> index f8fd379501bf..51a214ee75a7 100644
> --- a/drivers/nvdimm/pfn_devs.c
> +++ b/drivers/nvdimm/pfn_devs.c
> @@ -10,6 +10,7 @@
>   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
>   * General Public License for more details.
>   */
> +#include <linux/memremap.h>
>  #include <linux/blkdev.h>
>  #include <linux/device.h>
>  #include <linux/genhd.h>
> @@ -441,3 +442,185 @@ int nd_pfn_probe(struct device *dev, struct
> nd_namespace_common *ndns) return rc;
>  }
>  EXPORT_SYMBOL(nd_pfn_probe);
> +
> +/*
> + * We hotplug memory at section granularity, pad the reserved area from
> + * the previous section base to the namespace base address.
> + */
> +static unsigned long init_altmap_base(resource_size_t base)
> +{
> +	unsigned long base_pfn = PHYS_PFN(base);
> +
> +	return PFN_SECTION_ALIGN_DOWN(base_pfn);
> +}
> +
> +static unsigned long init_altmap_reserve(resource_size_t base)
> +{
> +	unsigned long reserve = PHYS_PFN(SZ_8K);
> +	unsigned long base_pfn = PHYS_PFN(base);
> +
> +	reserve += base_pfn - PFN_SECTION_ALIGN_DOWN(base_pfn);
> +	return reserve;
> +}
> +
> +static struct vmem_altmap *__nvdimm_setup_pfn(struct nd_pfn *nd_pfn,
> +		struct resource *res, struct vmem_altmap *altmap)
> +{
> +	struct nd_pfn_sb *pfn_sb = nd_pfn->pfn_sb;
> +	u64 offset = le64_to_cpu(pfn_sb->dataoff);
> +	u32 start_pad = __le32_to_cpu(pfn_sb->start_pad);
> +	u32 end_trunc = __le32_to_cpu(pfn_sb->end_trunc);
> +	struct nd_namespace_common *ndns = nd_pfn->ndns;
> +	struct nd_namespace_io *nsio = to_nd_namespace_io(&ndns->dev);
> +	resource_size_t base = nsio->res.start + start_pad;
> +	struct vmem_altmap __altmap = {
> +		.base_pfn = init_altmap_base(base),
> +		.reserve = init_altmap_reserve(base),
> +	};
> +
> +	memcpy(res, &nsio->res, sizeof(*res));
> +	res->start += start_pad;
> +	res->end -= end_trunc;
> +
> +	nd_pfn->mode = le32_to_cpu(nd_pfn->pfn_sb->mode);
> +	if (nd_pfn->mode == PFN_MODE_RAM) {
> +		if (offset < SZ_8K)
> +			return ERR_PTR(-EINVAL);
> +		nd_pfn->npfns = le64_to_cpu(pfn_sb->npfns);
> +		altmap = NULL;
> +	} else if (nd_pfn->mode == PFN_MODE_PMEM) {
> +		nd_pfn->npfns = (resource_size(res) - offset) / PAGE_SIZE;
> +		if (le64_to_cpu(nd_pfn->pfn_sb->npfns) > nd_pfn->npfns)
> +			dev_info(&nd_pfn->dev,
> +					"number of pfns truncated from %lld to %ld\n",
> +					le64_to_cpu(nd_pfn->pfn_sb->npfns),
> +					nd_pfn->npfns);
> +		memcpy(altmap, &__altmap, sizeof(*altmap));
> +		altmap->free = PHYS_PFN(offset - SZ_8K);
> +		altmap->alloc = 0;
> +	} else
> +		return ERR_PTR(-ENXIO);
> +
> +	return altmap;
> +}
> +
> +static int nd_pfn_init(struct nd_pfn *nd_pfn)
> +{
> +	struct nd_namespace_common *ndns = nd_pfn->ndns;
> +	u32 start_pad = 0, end_trunc = 0;
> +	resource_size_t start, size;
> +	struct nd_namespace_io *nsio;
> +	struct nd_region *nd_region;
> +	struct nd_pfn_sb *pfn_sb;
> +	unsigned long npfns;
> +	phys_addr_t offset;
> +	u64 checksum;
> +	int rc;
> +
> +	pfn_sb = devm_kzalloc(&nd_pfn->dev, sizeof(*pfn_sb), GFP_KERNEL);
> +	if (!pfn_sb)
> +		return -ENOMEM;
> +
> +	nd_pfn->pfn_sb = pfn_sb;
> +	rc = nd_pfn_validate(nd_pfn);
> +	if (rc == -ENODEV)
> +		/* no info block, do init */;
> +	else
> +		return rc;

Why not:
if (rc != -ENODEV)
	return  rc;
/* no info block, do init */


> +
> +	nd_region = to_nd_region(nd_pfn->dev.parent);
> +	if (nd_region->ro) {
> +		dev_info(&nd_pfn->dev,
> +				"%s is read-only, unable to init metadata\n",
> +				dev_name(&nd_region->dev));
> +		return -ENXIO;
> +	}
> +
> +	memset(pfn_sb, 0, sizeof(*pfn_sb));
> +
> +	/*
> +	 * Check if pmem collides with 'System RAM' when section aligned and
> +	 * trim it accordingly
> +	 */
> +	nsio = to_nd_namespace_io(&ndns->dev);
> +	start = PHYS_SECTION_ALIGN_DOWN(nsio->res.start);
> +	size = resource_size(&nsio->res);
> +	if (region_intersects(start, size, IORESOURCE_SYSTEM_RAM,
> +				IORES_DESC_NONE) == REGION_MIXED) {
> +
> +		start = nsio->res.start;
> +		start_pad = PHYS_SECTION_ALIGN_UP(start) - start;
> +	}
> +
> +	start = nsio->res.start;
> +	size = PHYS_SECTION_ALIGN_UP(start + size) - start;
> +	if (region_intersects(start, size, IORESOURCE_SYSTEM_RAM,
> +				IORES_DESC_NONE) == REGION_MIXED) {
> +		size = resource_size(&nsio->res);
> +		end_trunc = start + size - PHYS_SECTION_ALIGN_DOWN(start + size);
> +	}
> +
> +	if (start_pad + end_trunc)
> +		dev_info(&nd_pfn->dev, "%s section collision, truncate %d bytes\n",
> +				dev_name(&ndns->dev), start_pad + end_trunc);
> +
> +	/*
> +	 * Note, we use 64 here for the standard size of struct page,
> +	 * debugging options may cause it to be larger in which case the
> +	 * implementation will limit the pfns advertised through
> +	 * ->direct_access() to those that are included in the memmap.
> +	 */
> +	start += start_pad;
> +	size = resource_size(&nsio->res);
> +	npfns = (size - start_pad - end_trunc - SZ_8K) / SZ_4K;
> +	if (nd_pfn->mode == PFN_MODE_PMEM)
> +		offset = ALIGN(start + SZ_8K + 64 * npfns, nd_pfn->align)
> +			- start;
> +	else if (nd_pfn->mode == PFN_MODE_RAM)
> +		offset = ALIGN(start + SZ_8K, nd_pfn->align) - start;
> +	else
> +		return -ENXIO;
> +
> +	if (offset + start_pad + end_trunc >= size) {
> +		dev_err(&nd_pfn->dev, "%s unable to satisfy requested alignment\n",
> +				dev_name(&ndns->dev));
> +		return -ENXIO;
> +	}
> +
> +	npfns = (size - offset - start_pad - end_trunc) / SZ_4K;
> +	pfn_sb->mode = cpu_to_le32(nd_pfn->mode);
> +	pfn_sb->dataoff = cpu_to_le64(offset);
> +	pfn_sb->npfns = cpu_to_le64(npfns);
> +	memcpy(pfn_sb->signature, PFN_SIG, PFN_SIG_LEN);
> +	memcpy(pfn_sb->uuid, nd_pfn->uuid, 16);
> +	memcpy(pfn_sb->parent_uuid, nd_dev_to_uuid(&ndns->dev), 16);
> +	pfn_sb->version_major = cpu_to_le16(1);
> +	pfn_sb->version_minor = cpu_to_le16(1);
> +	pfn_sb->start_pad = cpu_to_le32(start_pad);
> +	pfn_sb->end_trunc = cpu_to_le32(end_trunc);
> +	checksum = nd_sb_checksum((struct nd_gen_sb *) pfn_sb);
> +	pfn_sb->checksum = cpu_to_le64(checksum);
> +
> +	return nvdimm_write_bytes(ndns, SZ_4K, pfn_sb, sizeof(*pfn_sb));
> +}
> +
> +/*
> + * Determine the effective resource range and vmem_altmap from an nd_pfn
> + * instance.
> + */
> +struct vmem_altmap *nvdimm_setup_pfn(struct nd_pfn *nd_pfn,
> +		struct resource *res, struct vmem_altmap *altmap)
> +{
> +	int rc;
> +
> +	if (!nd_pfn->uuid || !nd_pfn->ndns)
> +		return ERR_PTR(-ENODEV);
> +
> +	rc = nd_pfn_init(nd_pfn);
> +	if (rc)
> +		return ERR_PTR(rc);
> +
> +	/* we need a valid pfn_sb before we can init a vmem_altmap */
> +	return __nvdimm_setup_pfn(nd_pfn, res, altmap);
> +}
> +EXPORT_SYMBOL_GPL(nvdimm_setup_pfn);
> diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
> index 03bfb3422da1..616a16cd655b 100644
> --- a/drivers/nvdimm/pmem.c
> +++ b/drivers/nvdimm/pmem.c
> @@ -182,9 +182,6 @@ void pmem_release_disk(void *disk)
>  	put_disk(disk);
>  }
> 
> -static struct vmem_altmap *nvdimm_setup_pfn(struct nd_pfn *nd_pfn,
> -		struct resource *res, struct vmem_altmap *altmap);
> -
>  static int pmem_attach_disk(struct device *dev,
>  		struct nd_namespace_common *ndns)
>  {
> @@ -296,187 +293,6 @@ static int pmem_attach_disk(struct device *dev,
>  	return 0;
>  }
> 
> -static int nd_pfn_init(struct nd_pfn *nd_pfn)
> -{
> -	struct pmem_device *pmem = dev_get_drvdata(&nd_pfn->dev);
> -	struct nd_namespace_common *ndns = nd_pfn->ndns;
> -	u32 start_pad = 0, end_trunc = 0;
> -	resource_size_t start, size;
> -	struct nd_namespace_io *nsio;
> -	struct nd_region *nd_region;
> -	struct nd_pfn_sb *pfn_sb;
> -	unsigned long npfns;
> -	phys_addr_t offset;
> -	u64 checksum;
> -	int rc;
> -
> -	pfn_sb = devm_kzalloc(&nd_pfn->dev, sizeof(*pfn_sb), GFP_KERNEL);
> -	if (!pfn_sb)
> -		return -ENOMEM;
> -
> -	nd_pfn->pfn_sb = pfn_sb;
> -	rc = nd_pfn_validate(nd_pfn);
> -	if (rc == -ENODEV)
> -		/* no info block, do init */;
> -	else
> -		return rc;
> -
> -	nd_region = to_nd_region(nd_pfn->dev.parent);
> -	if (nd_region->ro) {
> -		dev_info(&nd_pfn->dev,
> -				"%s is read-only, unable to init metadata\n",
> -				dev_name(&nd_region->dev));
> -		return -ENXIO;
> -	}
> -
> -	memset(pfn_sb, 0, sizeof(*pfn_sb));
> -
> -	/*
> -	 * Check if pmem collides with 'System RAM' when section aligned and
> -	 * trim it accordingly
> -	 */
> -	nsio = to_nd_namespace_io(&ndns->dev);
> -	start = PHYS_SECTION_ALIGN_DOWN(nsio->res.start);
> -	size = resource_size(&nsio->res);
> -	if (region_intersects(start, size, IORESOURCE_SYSTEM_RAM,
> -				IORES_DESC_NONE) == REGION_MIXED) {
> -
> -		start = nsio->res.start;
> -		start_pad = PHYS_SECTION_ALIGN_UP(start) - start;
> -	}
> -
> -	start = nsio->res.start;
> -	size = PHYS_SECTION_ALIGN_UP(start + size) - start;
> -	if (region_intersects(start, size, IORESOURCE_SYSTEM_RAM,
> -				IORES_DESC_NONE) == REGION_MIXED) {
> -		size = resource_size(&nsio->res);
> -		end_trunc = start + size - PHYS_SECTION_ALIGN_DOWN(start + size);
> -	}
> -
> -	if (start_pad + end_trunc)
> -		dev_info(&nd_pfn->dev, "%s section collision, truncate %d bytes\n",
> -				dev_name(&ndns->dev), start_pad + end_trunc);
> -
> -	/*
> -	 * Note, we use 64 here for the standard size of struct page,
> -	 * debugging options may cause it to be larger in which case the
> -	 * implementation will limit the pfns advertised through
> -	 * ->direct_access() to those that are included in the memmap.
> -	 */
> -	start += start_pad;
> -	npfns = (pmem->size - start_pad - end_trunc - SZ_8K) / SZ_4K;
> -	if (nd_pfn->mode == PFN_MODE_PMEM)
> -		offset = ALIGN(start + SZ_8K + 64 * npfns, nd_pfn->align)
> -			- start;
> -	else if (nd_pfn->mode == PFN_MODE_RAM)
> -		offset = ALIGN(start + SZ_8K, nd_pfn->align) - start;
> -	else
> -		return -ENXIO;
> -
> -	if (offset + start_pad + end_trunc >= pmem->size) {
> -		dev_err(&nd_pfn->dev, "%s unable to satisfy requested alignment\n",
> -				dev_name(&ndns->dev));
> -		return -ENXIO;
> -	}
> -
> -	npfns = (pmem->size - offset - start_pad - end_trunc) / SZ_4K;
> -	pfn_sb->mode = cpu_to_le32(nd_pfn->mode);
> -	pfn_sb->dataoff = cpu_to_le64(offset);
> -	pfn_sb->npfns = cpu_to_le64(npfns);
> -	memcpy(pfn_sb->signature, PFN_SIG, PFN_SIG_LEN);
> -	memcpy(pfn_sb->uuid, nd_pfn->uuid, 16);
> -	memcpy(pfn_sb->parent_uuid, nd_dev_to_uuid(&ndns->dev), 16);
> -	pfn_sb->version_major = cpu_to_le16(1);
> -	pfn_sb->version_minor = cpu_to_le16(1);
> -	pfn_sb->start_pad = cpu_to_le32(start_pad);
> -	pfn_sb->end_trunc = cpu_to_le32(end_trunc);
> -	checksum = nd_sb_checksum((struct nd_gen_sb *) pfn_sb);
> -	pfn_sb->checksum = cpu_to_le64(checksum);
> -
> -	return nvdimm_write_bytes(ndns, SZ_4K, pfn_sb, sizeof(*pfn_sb));
> -}
> -
> -/*
> - * We hotplug memory at section granularity, pad the reserved area from
> - * the previous section base to the namespace base address.
> - */
> -static unsigned long init_altmap_base(resource_size_t base)
> -{
> -	unsigned long base_pfn = PHYS_PFN(base);
> -
> -	return PFN_SECTION_ALIGN_DOWN(base_pfn);
> -}
> -
> -static unsigned long init_altmap_reserve(resource_size_t base)
> -{
> -	unsigned long reserve = PHYS_PFN(SZ_8K);
> -	unsigned long base_pfn = PHYS_PFN(base);
> -
> -	reserve += base_pfn - PFN_SECTION_ALIGN_DOWN(base_pfn);
> -	return reserve;
> -}
> -
> -static struct vmem_altmap *__nvdimm_setup_pfn(struct nd_pfn *nd_pfn,
> -		struct resource *res, struct vmem_altmap *altmap)
> -{
> -	struct nd_pfn_sb *pfn_sb = nd_pfn->pfn_sb;
> -	u64 offset = le64_to_cpu(pfn_sb->dataoff);
> -	u32 start_pad = __le32_to_cpu(pfn_sb->start_pad);
> -	u32 end_trunc = __le32_to_cpu(pfn_sb->end_trunc);
> -	struct nd_namespace_common *ndns = nd_pfn->ndns;
> -	struct nd_namespace_io *nsio = to_nd_namespace_io(&ndns->dev);
> -	resource_size_t base = nsio->res.start + start_pad;
> -	struct vmem_altmap __altmap = {
> -		.base_pfn = init_altmap_base(base),
> -		.reserve = init_altmap_reserve(base),
> -	};
> -
> -	memcpy(res, &nsio->res, sizeof(*res));
> -	res->start += start_pad;
> -	res->end -= end_trunc;
> -
> -	nd_pfn->mode = le32_to_cpu(nd_pfn->pfn_sb->mode);
> -	if (nd_pfn->mode == PFN_MODE_RAM) {
> -		if (offset < SZ_8K)
> -			return ERR_PTR(-EINVAL);
> -		nd_pfn->npfns = le64_to_cpu(pfn_sb->npfns);
> -		altmap = NULL;
> -	} else if (nd_pfn->mode == PFN_MODE_PMEM) {
> -		nd_pfn->npfns = (resource_size(res) - offset) / PAGE_SIZE;
> -		if (le64_to_cpu(nd_pfn->pfn_sb->npfns) > nd_pfn->npfns)
> -			dev_info(&nd_pfn->dev,
> -					"number of pfns truncated from %lld to %ld\n",
> -					le64_to_cpu(nd_pfn->pfn_sb->npfns),
> -					nd_pfn->npfns);
> -		memcpy(altmap, &__altmap, sizeof(*altmap));
> -		altmap->free = PHYS_PFN(offset - SZ_8K);
> -		altmap->alloc = 0;
> -	} else
> -		return ERR_PTR(-ENXIO);
> -
> -	return altmap;
> -}
> -
> -/*
> - * Determine the effective resource range and vmem_altmap from an nd_pfn
> - * instance.
> - */
> -static struct vmem_altmap *nvdimm_setup_pfn(struct nd_pfn *nd_pfn,
> -		struct resource *res, struct vmem_altmap *altmap)
> -{
> -	int rc;
> -
> -	if (!nd_pfn->uuid || !nd_pfn->ndns)
> -		return ERR_PTR(-ENODEV);
> -
> -	rc = nd_pfn_init(nd_pfn);
> -	if (rc)
> -		return ERR_PTR(rc);
> -
> -	/* we need a valid pfn_sb before we can init a vmem_altmap */
> -	return __nvdimm_setup_pfn(nd_pfn, res, altmap);
> -}
> -
>  static int nd_pmem_probe(struct device *dev)
>  {
>  	struct nd_namespace_common *ndns;
> 
> _______________________________________________
> Linux-nvdimm mailing list
> Linux-nvdimm@...ts.01.org
> https://lists.01.org/mailman/listinfo/linux-nvdimm


-- 
Johannes Thumshirn                                          Storage
jthumshirn@...e.de                                +49 911 74053 689
SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: Felix Imendörffer, Jane Smithard, Graham Norton
HRB 21284 (AG Nürnberg)
Key fingerprint = EC38 9CAB C2C4 F25D 8600 D0D0 0393 969D 2D76 0850

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