Add helpers to determine if a page or folio is a device dax or fs dax
page or folio.

Signed-off-by: Alistair Popple <apopple@nvidia.com>
---
 include/linux/memremap.h | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/include/linux/memremap.h b/include/linux/memremap.h
index 0256a42..f2a8d13 100644
--- a/include/linux/memremap.h
+++ b/include/linux/memremap.h
@@ -187,6 +187,28 @@ static inline bool folio_is_device_coherent(const struct folio *folio)
 	return is_device_coherent_page(&folio->page);
 }
 
+static inline bool is_fsdax_page(const struct page *page)
+{
+	return is_zone_device_page(page) &&
+		page_pgmap(page)->type == MEMORY_DEVICE_FS_DAX;
+}
+
+static inline bool folio_is_fsdax(const struct folio *folio)
+{
+	return is_fsdax_page(&folio->page);
+}
+
+static inline bool is_device_dax_page(const struct page *page)
+{
+	return is_zone_device_page(page) &&
+		page_pgmap(page)->type == MEMORY_DEVICE_GENERIC;
+}
+
+static inline bool folio_is_device_dax(const struct folio *folio)
+{
+	return is_device_dax_page(&folio->page);
+}
+
 #ifdef CONFIG_ZONE_DEVICE
 void zone_device_page_init(struct page *page);
 void *memremap_pages(struct dev_pagemap *pgmap, int nid);
-- 
git-series 0.9.1

On 17.12.24 06:13, Alistair Popple wrote:
> Add helpers to determine if a page or folio is a device dax or fs dax
> page or folio.

... why is it "device_dax" but "fsdax" ? In particular because you wrote 
"fs dax" above.

I see "fsdax" getting used in some functions. But then, people usually 
say "devdax".

I'm fine either way (could be cleaned up later), just wondering about 
that slight "inconsistency".

So whatever you think is best, feel free to add

Acked-by: David Hildenbrand <david@redhat.com>

-- 
Cheers,

David / dhildenb