[PATCH v4 09/15] linux/mm.h: move devmap-related declarations to mm/devmap_managed.h

[Max Kellermann]

Prepare to reduce dependencies on linux/mm.h.

put_devmap_managed_page() is called by put_page().  Moving it to a
separate header allows us to move put_page() to a separate lean header
as well.

Signed-off-by: Max Kellermann <max.kellermann@xxxxxxxxx>
---
 include/linux/mm.h                | 25 +--------------------
 include/linux/mm/devmap_managed.h | 37 +++++++++++++++++++++++++++++++
 2 files changed, 38 insertions(+), 24 deletions(-)
 create mode 100644 include/linux/mm/devmap_managed.h

diff --git a/include/linux/mm.h b/include/linux/mm.h
index e6c2df977abc..61f1312a626e 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2,6 +2,7 @@
 #ifndef _LINUX_MM_H
 #define _LINUX_MM_H
 
+#include <linux/mm/devmap_managed.h>
 #include <linux/mm/folio_next.h>
 #include <linux/mm/folio_size.h>
 #include <linux/mm/page_address.h>
@@ -1357,30 +1358,6 @@ vm_fault_t finish_fault(struct vm_fault *vmf);
  *   back into memory.
  */
 
-#if defined(CONFIG_ZONE_DEVICE) && defined(CONFIG_FS_DAX)
-DECLARE_STATIC_KEY_FALSE(devmap_managed_key);
-
-bool __put_devmap_managed_page_refs(struct page *page, int refs);
-static inline bool put_devmap_managed_page_refs(struct page *page, int refs)
-{
-	if (!static_branch_unlikely(&devmap_managed_key))
-		return false;
-	if (!is_zone_device_page(page))
-		return false;
-	return __put_devmap_managed_page_refs(page, refs);
-}
-#else /* CONFIG_ZONE_DEVICE && CONFIG_FS_DAX */
-static inline bool put_devmap_managed_page_refs(struct page *page, int refs)
-{
-	return false;
-}
-#endif /* CONFIG_ZONE_DEVICE && CONFIG_FS_DAX */
-
-static inline bool put_devmap_managed_page(struct page *page)
-{
-	return put_devmap_managed_page_refs(page, 1);
-}
-
 /* 127: arbitrary random number, small enough to assemble well */
 #define folio_ref_zero_or_close_to_overflow(folio) \
 	((unsigned int) folio_ref_count(folio) + 127u <= 127u)
diff --git a/include/linux/mm/devmap_managed.h b/include/linux/mm/devmap_managed.h
new file mode 100644
index 000000000000..0773529d80b2
--- /dev/null
+++ b/include/linux/mm/devmap_managed.h
@@ -0,0 +1,37 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_MM_DEVMAP_MANAGED_H
+#define _LINUX_MM_DEVMAP_MANAGED_H
+
+#include <linux/types.h> // for bool
+
+struct page;
+
+#if defined(CONFIG_ZONE_DEVICE) && defined(CONFIG_FS_DAX)
+
+#include <linux/jump_label.h> // for DECLARE_STATIC_KEY_FALSE(), static_branch_unlikely()
+#include <linux/mmzone.h> // is_zone_device_page()
+
+DECLARE_STATIC_KEY_FALSE(devmap_managed_key);
+
+bool __put_devmap_managed_page_refs(struct page *page, int refs);
+static inline bool put_devmap_managed_page_refs(struct page *page, int refs)
+{
+	if (!static_branch_unlikely(&devmap_managed_key))
+		return false;
+	if (!is_zone_device_page(page))
+		return false;
+	return __put_devmap_managed_page_refs(page, refs);
+}
+#else /* CONFIG_ZONE_DEVICE && CONFIG_FS_DAX */
+static inline bool put_devmap_managed_page_refs(struct page *page, int refs)
+{
+	return false;
+}
+#endif /* CONFIG_ZONE_DEVICE && CONFIG_FS_DAX */
+
+static inline bool put_devmap_managed_page(struct page *page)
+{
+	return put_devmap_managed_page_refs(page, 1);
+}
+
+#endif /* _LINUX_MM_DEVMAP_MANAGED_H */
-- 
2.39.2