[PATCH 16/17] memremap: change devm_memremap_pages interface to use struct dev_pagemap

From: Christoph Hellwig
Date: Fri Dec 15 2017 - 09:11:54 EST

From: Logan Gunthorpe <logang@xxxxxxxxxxxx>

This new interface is similar to how struct device (and many others)
work. The caller initializes a 'struct dev_pagemap' as required
and calls 'devm_memremap_pages'. This allows the pagemap structure to
be embedded in another structure and thus container_of can be used. In
this way application specific members can be stored in a containing
struct.

This will be used by the P2P infrastructure and HMM could probably
be cleaned up to use it as well (instead of having it's own, similar
'hmm_devmem_pages_create' function).

Signed-off-by: Logan Gunthorpe <logang@xxxxxxxxxxxx>
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
drivers/dax/pmem.c | 20 +++++++++-------
drivers/nvdimm/nd.h | 9 ++++---
drivers/nvdimm/pfn_devs.c | 25 ++++++++++----------
drivers/nvdimm/pmem.c | 37 ++++++++++++++++-------------
drivers/nvdimm/pmem.h | 1 +
include/linux/memremap.h | 6 ++---
kernel/memremap.c | 50 ++++++++++++++++-----------------------
tools/testing/nvdimm/test/iomap.c | 7 +++---
8 files changed, 75 insertions(+), 80 deletions(-)

diff --git a/drivers/dax/pmem.c b/drivers/dax/pmem.c
index 8d8c852ba8f2..31b6ecce4c64 100644
--- a/drivers/dax/pmem.c
+++ b/drivers/dax/pmem.c
@@ -21,6 +21,7 @@
struct dax_pmem {
struct device *dev;
struct percpu_ref ref;
+ struct dev_pagemap pgmap;
struct completion cmp;
};

@@ -69,20 +70,23 @@ static int dax_pmem_probe(struct device *dev)
struct nd_namespace_common *ndns;
struct nd_dax *nd_dax = to_nd_dax(dev);
struct nd_pfn *nd_pfn = &nd_dax->nd_pfn;
- struct vmem_altmap __altmap, *altmap = NULL;

ndns = nvdimm_namespace_common_probe(dev);
if (IS_ERR(ndns))
return PTR_ERR(ndns);
nsio = to_nd_namespace_io(&ndns->dev);

+ dax_pmem = devm_kzalloc(dev, sizeof(*dax_pmem), GFP_KERNEL);
+ if (!dax_pmem)
+ return -ENOMEM;
+
/* parse the 'pfn' info block via ->rw_bytes */
rc = devm_nsio_enable(dev, nsio);
if (rc)
return rc;
- altmap = nvdimm_setup_pfn(nd_pfn, &res, &__altmap);
- if (IS_ERR(altmap))
- return PTR_ERR(altmap);
+ rc = nvdimm_setup_pfn(nd_pfn, &dax_pmem->pgmap);
+ if (rc)
+ return rc;
devm_nsio_disable(dev, nsio);

pfn_sb = nd_pfn->pfn_sb;
@@ -94,10 +98,6 @@ static int dax_pmem_probe(struct device *dev)
return -EBUSY;
}

- dax_pmem = devm_kzalloc(dev, sizeof(*dax_pmem), GFP_KERNEL);
- if (!dax_pmem)
- return -ENOMEM;
-
dax_pmem->dev = dev;
init_completion(&dax_pmem->cmp);
rc = percpu_ref_init(&dax_pmem->ref, dax_pmem_percpu_release, 0,
@@ -110,7 +110,8 @@ static int dax_pmem_probe(struct device *dev)
if (rc)
return rc;

- addr = devm_memremap_pages(dev, &res, &dax_pmem->ref, altmap);
+ dax_pmem->pgmap.ref = &dax_pmem->ref;
+ addr = devm_memremap_pages(dev, &dax_pmem->pgmap);
if (IS_ERR(addr))
return PTR_ERR(addr);

@@ -120,6 +121,7 @@ static int dax_pmem_probe(struct device *dev)
return rc;

/* adjust the dax_region resource to the start of data */
+ memcpy(&res, &dax_pmem->pgmap.res, sizeof(res));
res.start += le64_to_cpu(pfn_sb->dataoff);

rc = sscanf(dev_name(&ndns->dev), "namespace%d.%d", &region_id, &id);
diff --git a/drivers/nvdimm/nd.h b/drivers/nvdimm/nd.h
index e958f3724c41..8d6375ee0fda 100644
--- a/drivers/nvdimm/nd.h
+++ b/drivers/nvdimm/nd.h
@@ -368,15 +368,14 @@ unsigned int pmem_sector_size(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 nvdimm_setup_pfn(struct nd_pfn *nd_pfn, struct dev_pagemap *pgmap);
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)
+static inline int nvdimm_setup_pfn(struct nd_pfn *nd_pfn,
+ struct dev_pagemap *pgmap)
{
- return ERR_PTR(-ENXIO);
+ return -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 65cc171c721d..6f58615ddb85 100644
--- a/drivers/nvdimm/pfn_devs.c
+++ b/drivers/nvdimm/pfn_devs.c
@@ -541,9 +541,10 @@ static unsigned long init_altmap_reserve(resource_size_t base)
return reserve;
}

-static struct vmem_altmap *__nvdimm_setup_pfn(struct nd_pfn *nd_pfn,
- struct resource *res, struct vmem_altmap *altmap)
+static int __nvdimm_setup_pfn(struct nd_pfn *nd_pfn, struct dev_pagemap *pgmap)
{
+ struct resource *res = &pgmap->res;
+ struct vmem_altmap *altmap = &pgmap->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);
@@ -562,9 +563,9 @@ static struct vmem_altmap *__nvdimm_setup_pfn(struct nd_pfn *nd_pfn,

if (nd_pfn->mode == PFN_MODE_RAM) {
if (offset < SZ_8K)
- return ERR_PTR(-EINVAL);
+ return -EINVAL;
nd_pfn->npfns = le64_to_cpu(pfn_sb->npfns);
- altmap = NULL;
+ pgmap->altmap_valid = false;
} else if (nd_pfn->mode == PFN_MODE_PMEM) {
nd_pfn->npfns = PFN_SECTION_ALIGN_UP((resource_size(res)
- offset) / PAGE_SIZE);
@@ -576,10 +577,11 @@ static struct vmem_altmap *__nvdimm_setup_pfn(struct nd_pfn *nd_pfn,
memcpy(altmap, &__altmap, sizeof(*altmap));
altmap->free = PHYS_PFN(offset - SZ_8K);
altmap->alloc = 0;
+ pgmap->altmap_valid = true;
} else
- return ERR_PTR(-ENXIO);
+ return -ENXIO;

- return altmap;
+ return 0;
}

static int nd_pfn_init(struct nd_pfn *nd_pfn)
@@ -698,19 +700,18 @@ static int nd_pfn_init(struct nd_pfn *nd_pfn)
* 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 nvdimm_setup_pfn(struct nd_pfn *nd_pfn, struct dev_pagemap *pgmap)
{
int rc;

if (!nd_pfn->uuid || !nd_pfn->ndns)
- return ERR_PTR(-ENODEV);
+ return -ENODEV;

rc = nd_pfn_init(nd_pfn);
if (rc)
- return ERR_PTR(rc);
+ return rc;

- /* we need a valid pfn_sb before we can init a vmem_altmap */
- return __nvdimm_setup_pfn(nd_pfn, res, altmap);
+ /* we need a valid pfn_sb before we can init a dev_pagemap */
+ return __nvdimm_setup_pfn(nd_pfn, pgmap);
}
EXPORT_SYMBOL_GPL(nvdimm_setup_pfn);
diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
index 7fbc5c5dc8e1..cf074b1ce219 100644
--- a/drivers/nvdimm/pmem.c
+++ b/drivers/nvdimm/pmem.c
@@ -298,34 +298,34 @@ static int pmem_attach_disk(struct device *dev,
{
struct nd_namespace_io *nsio = to_nd_namespace_io(&ndns->dev);
struct nd_region *nd_region = to_nd_region(dev->parent);
- struct vmem_altmap __altmap, *altmap = NULL;
int nid = dev_to_node(dev), fua, wbc;
struct resource *res = &nsio->res;
+ struct resource bb_res;
struct nd_pfn *nd_pfn = NULL;
struct dax_device *dax_dev;
struct nd_pfn_sb *pfn_sb;
struct pmem_device *pmem;
- struct resource pfn_res;
struct request_queue *q;
struct device *gendev;
struct gendisk *disk;
void *addr;
+ int rc;
+
+ pmem = devm_kzalloc(dev, sizeof(*pmem), GFP_KERNEL);
+ if (!pmem)
+ return -ENOMEM;

/* while nsio_rw_bytes is active, parse a pfn info block if present */
if (is_nd_pfn(dev)) {
nd_pfn = to_nd_pfn(dev);
- altmap = nvdimm_setup_pfn(nd_pfn, &pfn_res, &__altmap);
- if (IS_ERR(altmap))
- return PTR_ERR(altmap);
+ rc = nvdimm_setup_pfn(nd_pfn, &pmem->pgmap);
+ if (rc)
+ return rc;
}

/* we're attaching a block device, disable raw namespace access */
devm_nsio_disable(dev, nsio);

- pmem = devm_kzalloc(dev, sizeof(*pmem), GFP_KERNEL);
- if (!pmem)
- return -ENOMEM;
-
dev_set_drvdata(dev, pmem);
pmem->phys_addr = res->start;
pmem->size = resource_size(res);
@@ -350,19 +350,22 @@ static int pmem_attach_disk(struct device *dev,
return -ENOMEM;

pmem->pfn_flags = PFN_DEV;
+ pmem->pgmap.ref = &q->q_usage_counter;
if (is_nd_pfn(dev)) {
- addr = devm_memremap_pages(dev, &pfn_res, &q->q_usage_counter,
- altmap);
+ addr = devm_memremap_pages(dev, &pmem->pgmap);
pfn_sb = nd_pfn->pfn_sb;
pmem->data_offset = le64_to_cpu(pfn_sb->dataoff);
- pmem->pfn_pad = resource_size(res) - resource_size(&pfn_res);
+ pmem->pfn_pad = resource_size(res) -
+ resource_size(&pmem->pgmap.res);
pmem->pfn_flags |= PFN_MAP;
- res = &pfn_res; /* for badblocks populate */
- res->start += pmem->data_offset;
+ memcpy(&bb_res, &pmem->pgmap.res, sizeof(bb_res));
+ bb_res.start += pmem->data_offset;
} else if (pmem_should_map_pages(dev)) {
- addr = devm_memremap_pages(dev, &nsio->res,
- &q->q_usage_counter, NULL);
+ memcpy(&pmem->pgmap.res, &nsio->res, sizeof(pmem->pgmap.res));
+ pmem->pgmap.altmap_valid = false;
+ addr = devm_memremap_pages(dev, &pmem->pgmap);
pmem->pfn_flags |= PFN_MAP;
+ memcpy(&bb_res, &pmem->pgmap.res, sizeof(bb_res));
} else
addr = devm_memremap(dev, pmem->phys_addr,
pmem->size, ARCH_MEMREMAP_PMEM);
@@ -401,7 +404,7 @@ static int pmem_attach_disk(struct device *dev,
/ 512);
if (devm_init_badblocks(dev, &pmem->bb))
return -ENOMEM;
- nvdimm_badblocks_populate(nd_region, &pmem->bb, res);
+ nvdimm_badblocks_populate(nd_region, &pmem->bb, &bb_res);
disk->bb = &pmem->bb;

dax_dev = alloc_dax(pmem, disk->disk_name, &pmem_dax_ops);
diff --git a/drivers/nvdimm/pmem.h b/drivers/nvdimm/pmem.h
index 6a3cd2a10db6..a64ebc78b5df 100644
--- a/drivers/nvdimm/pmem.h
+++ b/drivers/nvdimm/pmem.h
@@ -22,6 +22,7 @@ struct pmem_device {
struct badblocks bb;
struct dax_device *dax_dev;
struct gendisk *disk;
+ struct dev_pagemap pgmap;
};

long __pmem_direct_access(struct pmem_device *pmem, pgoff_t pgoff,
diff --git a/include/linux/memremap.h b/include/linux/memremap.h
index 1cb5f39d25c1..7b4899c06f49 100644
--- a/include/linux/memremap.h
+++ b/include/linux/memremap.h
@@ -123,8 +123,7 @@ struct dev_pagemap {
};

#ifdef CONFIG_ZONE_DEVICE
-void *devm_memremap_pages(struct device *dev, struct resource *res,
- struct percpu_ref *ref, struct vmem_altmap *altmap);
+void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap);
struct dev_pagemap *get_dev_pagemap(unsigned long pfn,
struct dev_pagemap *pgmap);

@@ -134,8 +133,7 @@ void vmem_altmap_free(struct vmem_altmap *altmap, unsigned long nr_pfns);
static inline bool is_zone_device_page(const struct page *page);
#else
static inline void *devm_memremap_pages(struct device *dev,
- struct resource *res, struct percpu_ref *ref,
- struct vmem_altmap *altmap)
+ struct dev_pagemap *pgmap)
{
/*
* Fail attempts to call devm_memremap_pages() without
diff --git a/kernel/memremap.c b/kernel/memremap.c
index 97782215bbd4..fd0e7c44e6bd 100644
--- a/kernel/memremap.c
+++ b/kernel/memremap.c
@@ -275,9 +275,10 @@ static unsigned long pfn_end(struct dev_pagemap *pgmap)
#define for_each_device_pfn(pfn, map) \
for (pfn = pfn_first(map); pfn < pfn_end(map); pfn++)

-static void devm_memremap_pages_release(struct device *dev, void *data)
+static void devm_memremap_pages_release(void *data)
{
struct dev_pagemap *pgmap = data;
+ struct device *dev = pgmap->dev;
struct resource *res = &pgmap->res;
resource_size_t align_start, align_size;
unsigned long pfn;
@@ -316,29 +317,34 @@ static struct dev_pagemap *find_dev_pagemap(resource_size_t phys)
/**
* devm_memremap_pages - remap and provide memmap backing for the given resource
* @dev: hosting device for @res
- * @res: "host memory" address range
- * @ref: a live per-cpu reference count
- * @altmap: optional descriptor for allocating the memmap from @res
+ * @pgmap: pointer to a struct dev_pgmap
*
* Notes:
- * 1/ @ref must be 'live' on entry and 'dead' before devm_memunmap_pages() time
- * (or devm release event). The expected order of events is that @ref has
+ * 1/ At a minimum the res, ref and type members of @pgmap must be initialized
+ * by the caller before passing it to this function
+ *
+ * 2/ The altmap field may optionally be initialized, in which case altmap_valid
+ * must be set to true
+ *
+ * 3/ pgmap.ref must be 'live' on entry and 'dead' before devm_memunmap_pages()
+ * time (or devm release event). The expected order of events is that ref has
* been through percpu_ref_kill() before devm_memremap_pages_release(). The
* wait for the completion of all references being dropped and
* percpu_ref_exit() must occur after devm_memremap_pages_release().
*
- * 2/ @res is expected to be a host memory range that could feasibly be
+ * 4/ res is expected to be a host memory range that could feasibly be
* treated as a "System RAM" range, i.e. not a device mmio range, but
* this is not enforced.
*/
-void *devm_memremap_pages(struct device *dev, struct resource *res,
- struct percpu_ref *ref, struct vmem_altmap *altmap)
+void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap)
{
resource_size_t align_start, align_size, align_end;
+ struct vmem_altmap *altmap = pgmap->altmap_valid ?
+ &pgmap->altmap : NULL;
unsigned long pfn, pgoff, order;
pgprot_t pgprot = PAGE_KERNEL;
- struct dev_pagemap *pgmap;
int error, nid, is_ram, i = 0;
+ struct resource *res = &pgmap->res;

align_start = res->start & ~(SECTION_SIZE - 1);
align_size = ALIGN(res->start + resource_size(res), SECTION_SIZE)
@@ -355,26 +361,10 @@ void *devm_memremap_pages(struct device *dev, struct resource *res,
if (is_ram == REGION_INTERSECTS)
return __va(res->start);

- if (!ref)
+ if (!pgmap->ref)
return ERR_PTR(-EINVAL);

- pgmap = devres_alloc_node(devm_memremap_pages_release,
- sizeof(*pgmap), GFP_KERNEL, dev_to_node(dev));
- if (!pgmap)
- return ERR_PTR(-ENOMEM);
-
- memcpy(&pgmap->res, res, sizeof(*res));
-
pgmap->dev = dev;
- if (altmap) {
- memcpy(&pgmap->altmap, altmap, sizeof(*altmap));
- pgmap->altmap_valid = true;
- }
- pgmap->ref = ref;
- pgmap->type = MEMORY_DEVICE_HOST;
- pgmap->page_fault = NULL;
- pgmap->page_free = NULL;
- pgmap->data = NULL;

mutex_lock(&pgmap_lock);
error = 0;
@@ -422,11 +412,13 @@ void *devm_memremap_pages(struct device *dev, struct resource *res,
*/
list_del(&page->lru);
page->pgmap = pgmap;
- percpu_ref_get(ref);
+ percpu_ref_get(pgmap->ref);
if (!(++i % 1024))
cond_resched();
}
- devres_add(dev, pgmap);
+
+ devm_add_action(dev, devm_memremap_pages_release, pgmap);
+
return __va(res->start);

err_add_memory:
diff --git a/tools/testing/nvdimm/test/iomap.c b/tools/testing/nvdimm/test/iomap.c
index e1f75a1914a1..ff9d3a5825e1 100644
--- a/tools/testing/nvdimm/test/iomap.c
+++ b/tools/testing/nvdimm/test/iomap.c
@@ -104,15 +104,14 @@ void *__wrap_devm_memremap(struct device *dev, resource_size_t offset,
}
EXPORT_SYMBOL(__wrap_devm_memremap);

-void *__wrap_devm_memremap_pages(struct device *dev, struct resource *res,
- struct percpu_ref *ref, struct vmem_altmap *altmap)
+void *__wrap_devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap)
{
- resource_size_t offset = res->start;
+ resource_size_t offset = pgmap->res.start;
struct nfit_test_resource *nfit_res = get_nfit_res(offset);

if (nfit_res)
return nfit_res->buf + offset - nfit_res->res.start;
- return devm_memremap_pages(dev, res, ref, altmap);
+ return devm_memremap_pages(dev, pgmap);
}
EXPORT_SYMBOL(__wrap_devm_memremap_pages);

--
2.14.2