When a ZONE_DEVICE page refcount reach 1 it means it is free and nobody
is holding a reference on it (only device to which the memory belong do).
Add a callback and call it when that happen so device driver can implement
their own free page management.
Signed-off-by: Jérôme Glisse <jglisse@xxxxxxxxxx>
Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
Cc: Ross Zwisler <ross.zwisler@xxxxxxxxxxxxxxx>
---
drivers/dax/pmem.c | 3 ++-
drivers/nvdimm/pmem.c | 5 +++--
include/linux/memremap.h | 17 ++++++++++++++---
kernel/memremap.c | 14 +++++++++++++-
tools/testing/nvdimm/test/iomap.c | 2 +-
5 files changed, 33 insertions(+), 8 deletions(-)
diff --git a/drivers/dax/pmem.c b/drivers/dax/pmem.c
index 033f49b3..66af7b1 100644
--- a/drivers/dax/pmem.c
+++ b/drivers/dax/pmem.c
@@ -111,7 +111,8 @@ static int dax_pmem_probe(struct device *dev)
if (rc)
return rc;
- addr = devm_memremap_pages(dev, &res, &dax_pmem->ref, altmap);
+ addr = devm_memremap_pages(dev, &res, &dax_pmem->ref,
+ altmap, NULL, NULL);
if (IS_ERR(addr))
return PTR_ERR(addr);
diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
index 8755317..f2f1904 100644
--- a/drivers/nvdimm/pmem.c
+++ b/drivers/nvdimm/pmem.c
@@ -282,7 +282,7 @@ static int pmem_attach_disk(struct device *dev,
pmem->pfn_flags = PFN_DEV;
if (is_nd_pfn(dev)) {
addr = devm_memremap_pages(dev, &pfn_res, &q->q_usage_counter,
- altmap);
+ altmap, NULL, NULL);
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);
@@ -291,7 +291,8 @@ static int pmem_attach_disk(struct device *dev,
res->start += pmem->data_offset;
} else if (pmem_should_map_pages(dev)) {
addr = devm_memremap_pages(dev, &nsio->res,
- &q->q_usage_counter, NULL);
+ &q->q_usage_counter,
+ NULL, NULL, NULL);
pmem->pfn_flags |= PFN_MAP;
} else
addr = devm_memremap(dev, pmem->phys_addr,
diff --git a/include/linux/memremap.h b/include/linux/memremap.h
index aee8477..582561f 100644
--- a/include/linux/memremap.h
+++ b/include/linux/memremap.h
@@ -35,23 +35,31 @@ static inline struct vmem_altmap *to_vmem_altmap(unsigned long memmap_start)
}
#endif
+typedef void (*dev_page_free_t)(struct page *page, void *data);
+
/**
* struct dev_pagemap - metadata for ZONE_DEVICE mappings
+ * @page_free: free page callback when page refcount reach 1
* @altmap: pre-allocated/reserved memory for vmemmap allocations
* @res: physical address range covered by @ref
* @ref: reference count that pins the devm_memremap_pages() mapping
* @dev: host device of the mapping for debug
+ * @data: privata data pointer for page_free
*/
struct dev_pagemap {
+ dev_page_free_t page_free;
struct vmem_altmap *altmap;
const struct resource *res;
struct percpu_ref *ref;
struct device *dev;
+ void *data;
};
#ifdef CONFIG_ZONE_DEVICE
void *devm_memremap_pages(struct device *dev, struct resource *res,
- struct percpu_ref *ref, struct vmem_altmap *altmap);
+ struct percpu_ref *ref, struct vmem_altmap *altmap,
+ dev_page_free_t page_free,
+ void *data);
struct dev_pagemap *find_dev_pagemap(resource_size_t phys);
int devm_memunmap_pages(struct device *dev, void *start);
@@ -62,8 +70,11 @@ static inline bool dev_page_allow_migrate(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 resource *res,
+ struct percpu_ref *ref,
+ struct vmem_altmap *altmap,
+ dev_page_free_t page_free,
+ void *data)
{
/*
* Fail attempts to call devm_memremap_pages() without
diff --git a/kernel/memremap.c b/kernel/memremap.c
index f0d4ea2..7e47e64 100644
--- a/kernel/memremap.c
+++ b/kernel/memremap.c
@@ -190,6 +190,12 @@ EXPORT_SYMBOL(get_zone_device_page);
void put_zone_device_page(struct page *page)
{
+ /*
+ * If refcount is 1 then page is freed and refcount is stable as nobody
+ * holds a reference on the page.
+ */
+ if (page->pgmap->page_free && page_count(page) == 1)
+ page->pgmap->page_free(page, page->pgmap->data);
put_dev_pagemap(page->pgmap);
}
EXPORT_SYMBOL(put_zone_device_page);
@@ -270,6 +276,8 @@ struct dev_pagemap *find_dev_pagemap(resource_size_t phys)
* @res: "host memory" address range
* @ref: a live per-cpu reference count
* @altmap: optional descriptor for allocating the memmap from @res
+ * @page_free: callback call when page refcount reach 1 ie it is free
+ * @data: privata data pointer for page_free
*
* Notes:
* 1/ @ref must be 'live' on entry and 'dead' before devm_memunmap_pages() time
@@ -280,7 +288,9 @@ struct dev_pagemap *find_dev_pagemap(resource_size_t phys)
* this is not enforced.
*/
void *devm_memremap_pages(struct device *dev, struct resource *res,
- struct percpu_ref *ref, struct vmem_altmap *altmap)
+ struct percpu_ref *ref, struct vmem_altmap *altmap,
+ dev_page_free_t page_free,
+ void *data)
{
resource_size_t key, align_start, align_size, align_end;
pgprot_t pgprot = PAGE_KERNEL;
@@ -322,6 +332,8 @@ void *devm_memremap_pages(struct device *dev, struct resource *res,
}
pgmap->ref = ref;
pgmap->res = &page_map->res;
+ pgmap->page_free = page_free;
+ pgmap->data = data;
mutex_lock(&pgmap_lock);
error = 0;
diff --git a/tools/testing/nvdimm/test/iomap.c b/tools/testing/nvdimm/test/iomap.c
index 64cae1a..9992a7c 100644
--- a/tools/testing/nvdimm/test/iomap.c
+++ b/tools/testing/nvdimm/test/iomap.c
@@ -112,7 +112,7 @@ void *__wrap_devm_memremap_pages(struct device *dev, struct resource *res,
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, res, ref, altmap, NULL, NULL);
}
EXPORT_SYMBOL(__wrap_devm_memremap_pages);
--
2.4.3
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