[PATCH 1/2] mm: move get_dev_pagemap out of line

Christoph Hellwig
2017-12-05T00:30:17Z

This is a pretty big function, which should be out of line in general,
and a no-op stub if CONFIG_ZONE_DEVICЕ is not set.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
include/linux/memremap.h | 42 +++++-------------------------------------
kernel/memremap.c | 36 ++++++++++++++++++++++++++++++++++--
2 files changed, 39 insertions(+), 39 deletions(-)

diff --git a/include/linux/memremap.h b/include/linux/memremap.h
index 10d23c367048..f24e0c71d6a6 100644
--- a/include/linux/memremap.h
+++ b/include/linux/memremap.h
@@ -136,8 +136,8 @@ struct dev_pagemap {
#ifdef CONFIG_ZONE_DEVICE
void *devm_memremap_pages(struct device *dev, struct resource *res,
struct percpu_ref *ref, struct vmem_altmap *altmap);
-struct dev_pagemap *find_dev_pagemap(resource_size_t phys);
-
+struct dev_pagemap *get_dev_pagemap(unsigned long pfn,
+ struct dev_pagemap *pgmap);
static inline bool is_zone_device_page(const struct page *page);
#else
static inline void *devm_memremap_pages(struct device *dev,
@@ -153,11 +153,12 @@ static inline void *devm_memremap_pages(struct device *dev,
return ERR_PTR(-ENXIO);
}

-static inline struct dev_pagemap *find_dev_pagemap(resource_size_t phys)
+static inline struct dev_pagemap *get_dev_pagemap(unsigned long pfn,
+ struct dev_pagemap *pgmap)
{
return NULL;
}
-#endif
+#endif /* CONFIG_ZONE_DEVICE */

#if defined(CONFIG_DEVICE_PRIVATE) || defined(CONFIG_DEVICE_PUBLIC)
static inline bool is_device_private_page(const struct page *page)
@@ -173,39 +174,6 @@ static inline bool is_device_public_page(const struct page *page)
}
#endif /* CONFIG_DEVICE_PRIVATE || CONFIG_DEVICE_PUBLIC */

-/**
- * get_dev_pagemap() - take a new live reference on the dev_pagemap for @pfn
- * @pfn: page frame number to lookup page_map
- * @pgmap: optional known pgmap that already has a reference
- *
- * @pgmap allows the overhead of a lookup to be bypassed when @pfn lands in the
- * same mapping.
- */
-static inline struct dev_pagemap *get_dev_pagemap(unsigned long pfn,
- struct dev_pagemap *pgmap)
-{
- const struct resource *res = pgmap ? pgmap->res : NULL;
- resource_size_t phys = PFN_PHYS(pfn);
-
- /*
- * In the cached case we're already holding a live reference so
- * we can simply do a blind increment
- */
- if (res && phys >= res->start && phys <= res->end) {
- percpu_ref_get(pgmap->ref);
- return pgmap;
- }
-
- /* fall back to slow path lookup */
- rcu_read_lock();
- pgmap = find_dev_pagemap(phys);
- if (pgmap && !percpu_ref_tryget_live(pgmap->ref))
- pgmap = NULL;
- rcu_read_unlock();
-
- return pgmap;
-}
-
static inline void put_dev_pagemap(struct dev_pagemap *pgmap)
{
if (pgmap)
diff --git a/kernel/memremap.c b/kernel/memremap.c
index 403ab9cdb949..f0b54eca85b0 100644
--- a/kernel/memremap.c
+++ b/kernel/memremap.c
@@ -314,7 +314,7 @@ static void devm_memremap_pages_release(struct device *dev, void *data)
}

/* assumes rcu_read_lock() held at entry */
-struct dev_pagemap *find_dev_pagemap(resource_size_t phys)
+static struct dev_pagemap *find_dev_pagemap(resource_size_t phys)
{
struct page_map *page_map;

@@ -500,8 +500,40 @@ struct vmem_altmap *to_vmem_altmap(unsigned long memmap_start)

return pgmap ? pgmap->altmap : NULL;
}
-#endif /* CONFIG_ZONE_DEVICE */

+/**
+ * get_dev_pagemap() - take a new live reference on the dev_pagemap for @pfn
+ * @pfn: page frame number to lookup page_map
+ * @pgmap: optional known pgmap that already has a reference
+ *
+ * @pgmap allows the overhead of a lookup to be bypassed when @pfn lands in the
+ * same mapping.
+ */
+struct dev_pagemap *get_dev_pagemap(unsigned long pfn,
+ struct dev_pagemap *pgmap)
+{
+ const struct resource *res = pgmap ? pgmap->res : NULL;
+ resource_size_t phys = PFN_PHYS(pfn);
+
+ /*
+ * In the cached case we're already holding a live reference so
+ * we can simply do a blind increment
+ */
+ if (res && phys >= res->start && phys <= res->end) {
+ percpu_ref_get(pgmap->ref);
+ return pgmap;
+ }
+
+ /* fall back to slow path lookup */
+ rcu_read_lock();
+ pgmap = find_dev_pagemap(phys);
+ if (pgmap && !percpu_ref_tryget_live(pgmap->ref))
+ pgmap = NULL;
+ rcu_read_unlock();
+
+ return pgmap;
+}
+#endif /* CONFIG_ZONE_DEVICE */

#if IS_ENABLED(CONFIG_DEVICE_PRIVATE) || IS_ENABLED(CONFIG_DEVICE_PUBLIC)
void put_zone_device_private_or_public_page(struct page *page)
--
2.14.2