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[V5,3/4] mm: add a function to differentiate the pages is from DAX device memory

Message ID 044309496afbb4121447dff6a453bd6b96d6068d.1536342881.git.yi.z.zhang@linux.intel.com (mailing list archive)
State New, archived
Headers show
Series Fix kvm misconceives NVDIMM pages as reserved mmio | expand

Commit Message

Zhang, Yi Sept. 7, 2018, 6:03 p.m. UTC 
DAX driver hotplug the device memory and move it to memory zone, these
pages will be marked reserved flag, however, some other kernel componet
will misconceive these pages are reserved mmio (ex: we map these dev_dax
or fs_dax pages to kvm for DIMM/NVDIMM backend). Together with the type
MEMORY_DEVICE_FS_DAX, we can use is_dax_page() to differentiate the pages
is DAX device memory or not.

Signed-off-by: Zhang Yi <yi.z.zhang@linux.intel.com>
Signed-off-by: Zhang Yu <yu.c.zhang@linux.intel.com>
Acked-by: Jan Kara <jack@suse.cz>
---
 include/linux/mm.h | 12 ++++++++++++
 1 file changed, 12 insertions(+)
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Patch

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 68a5121..de5cbc3 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -889,6 +889,13 @@  static inline bool is_device_public_page(const struct page *page)
 		page->pgmap->type == MEMORY_DEVICE_PUBLIC;
 }
 
+static inline bool is_dax_page(const struct page *page)
+{
+	return is_zone_device_page(page) &&
+		(page->pgmap->type == MEMORY_DEVICE_FS_DAX ||
+		page->pgmap->type == MEMORY_DEVICE_DEV_DAX);
+}
+
 #else /* CONFIG_DEV_PAGEMAP_OPS */
 static inline void dev_pagemap_get_ops(void)
 {
@@ -912,6 +919,11 @@  static inline bool is_device_public_page(const struct page *page)
 {
 	return false;
 }
+
+static inline bool is_dax_page(const struct page *page)
+{
+	return false;
+}
 #endif /* CONFIG_DEV_PAGEMAP_OPS */
 
 static inline void get_page(struct page *page)