sysctl: add and use base directory declarer and registration helper

[linux-block.git] / include / linux / memremap.h

diff --git a/include/linux/memremap.h b/include/linux/memremap.h
index a8bc588fe7aa8b2d0287484430ba9e79916b5971..1fafcc38acbad66229442a33699d7faa4a73dd58 100644 (file)
--- a/include/linux/memremap.h
+++ b/include/linux/memremap.h
@@ -88,6 +88,11 @@ struct dev_pagemap_ops {
  * @done: completion for @ref
  * @type: memory type: see MEMORY_* in memory_hotplug.h
  * @flags: PGMAP_* flags to specify defailed behavior
+ * @vmemmap_shift: structural definition of how the vmemmap page metadata
+ *      is populated, specifically the metadata page order.
+ *     A zero value (default) uses base pages as the vmemmap metadata
+ *     representation. A bigger value will set up compound struct pages
+ *     of the requested order value.
  * @ops: method table
  * @owner: an opaque pointer identifying the entity that manages this
  *     instance.  Used by various helpers to make sure that no
@@ -102,6 +107,7 @@ struct dev_pagemap {
        struct completion done;
        enum memory_type type;
        unsigned int flags;
+       unsigned long vmemmap_shift;
        const struct dev_pagemap_ops *ops;
        void *owner;
        int nr_range;
@@ -118,6 +124,11 @@ static inline struct vmem_altmap *pgmap_altmap(struct dev_pagemap *pgmap)
        return NULL;
 }
 
+static inline unsigned long pgmap_vmemmap_nr(struct dev_pagemap *pgmap)
+{
+       return 1 << pgmap->vmemmap_shift;
+}
+
 #ifdef CONFIG_ZONE_DEVICE
 void *memremap_pages(struct dev_pagemap *pgmap, int nid);
 void memunmap_pages(struct dev_pagemap *pgmap);