[PATCH v2 2/6] mm/devm_memremap_pages: Introduce devm_memunmap_pages

[Dan Williams <dan.j.williams@xxxxxxxxx>]

Use the new devm_relase_action() facility to allow
devm_memremap_pages_release() to be manually triggered.

Cc: Logan Gunthorpe <logang@xxxxxxxxxxxx>
Cc: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Reviewed-by: Ira Weiny <ira.weiny@xxxxxxxxx>
Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
---
 include/linux/memremap.h |    6 ++++++
 kernel/memremap.c        |    6 ++++++
 2 files changed, 12 insertions(+)

diff --git a/include/linux/memremap.h b/include/linux/memremap.h
index f0628660d541..7601ee314c4a 100644
--- a/include/linux/memremap.h
+++ b/include/linux/memremap.h
@@ -100,6 +100,7 @@ struct dev_pagemap {
 
 #ifdef CONFIG_ZONE_DEVICE
 void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap);
+void devm_memunmap_pages(struct device *dev, struct dev_pagemap *pgmap);
 struct dev_pagemap *get_dev_pagemap(unsigned long pfn,
 		struct dev_pagemap *pgmap);
 
@@ -118,6 +119,11 @@ static inline void *devm_memremap_pages(struct device *dev,
 	return ERR_PTR(-ENXIO);
 }
 
+static inline void devm_memunmap_pages(struct device *dev,
+		struct dev_pagemap *pgmap)
+{
+}
+
 static inline struct dev_pagemap *get_dev_pagemap(unsigned long pfn,
 		struct dev_pagemap *pgmap)
 {
diff --git a/kernel/memremap.c b/kernel/memremap.c
index a856cb5ff192..65afbacab44e 100644
--- a/kernel/memremap.c
+++ b/kernel/memremap.c
@@ -266,6 +266,12 @@ void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap)
 }
 EXPORT_SYMBOL_GPL(devm_memremap_pages);
 
+void devm_memunmap_pages(struct device *dev, struct dev_pagemap *pgmap)
+{
+	devm_release_action(dev, devm_memremap_pages_release, pgmap);
+}
+EXPORT_SYMBOL_GPL(devm_memunmap_pages);
+
 unsigned long vmem_altmap_offset(struct vmem_altmap *altmap)
 {
 	/* number of pfns from base where pfn_to_page() is valid */