[PATCH v2] mm: Move page_mapping_file to pagemap.h

["Matthew Wilcox (Oracle)" <willy@infradead.org>]

page_mapping_file() is only used by some architectures, and then it
is usually only used in one place.  Make it a static inline function
so other architectures don't have to carry this dead code.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
v2: Ensure pagemap.h is included in all the files which use page_mapping_file
 arch/arm/mm/copypage-v4mc.c   |  1 +
 arch/arm/mm/copypage-v6.c     |  1 +
 arch/arm/mm/copypage-xscale.c |  1 +
 arch/csky/abiv1/cacheflush.c  |  1 +
 arch/mips/mm/cache.c          |  1 +
 arch/nios2/mm/cacheflush.c    |  1 +
 arch/sh/mm/cache-sh4.c        |  1 +
 arch/sh/mm/cache-sh7705.c     |  1 +
 arch/sparc/mm/tlb.c           |  1 +
 include/linux/mm.h            |  1 -
 include/linux/pagemap.h       | 10 ++++++++++
 mm/util.c                     | 10 ----------
 12 files changed, 19 insertions(+), 11 deletions(-)

diff --git a/arch/arm/mm/copypage-v4mc.c b/arch/arm/mm/copypage-v4mc.c
index 44f7292ec27b..f1da3b439b96 100644
--- a/arch/arm/mm/copypage-v4mc.c
+++ b/arch/arm/mm/copypage-v4mc.c
@@ -13,6 +13,7 @@
 #include <linux/init.h>
 #include <linux/mm.h>
 #include <linux/highmem.h>
+#include <linux/pagemap.h>
 
 #include <asm/tlbflush.h>
 #include <asm/cacheflush.h>
diff --git a/arch/arm/mm/copypage-v6.c b/arch/arm/mm/copypage-v6.c
index 6a769a6c314e..d8a115de5507 100644
--- a/arch/arm/mm/copypage-v6.c
+++ b/arch/arm/mm/copypage-v6.c
@@ -8,6 +8,7 @@
 #include <linux/spinlock.h>
 #include <linux/mm.h>
 #include <linux/highmem.h>
+#include <linux/pagemap.h>
 
 #include <asm/shmparam.h>
 #include <asm/tlbflush.h>
diff --git a/arch/arm/mm/copypage-xscale.c b/arch/arm/mm/copypage-xscale.c
index eb5d338657d1..bcb485620a05 100644
--- a/arch/arm/mm/copypage-xscale.c
+++ b/arch/arm/mm/copypage-xscale.c
@@ -13,6 +13,7 @@
 #include <linux/init.h>
 #include <linux/mm.h>
 #include <linux/highmem.h>
+#include <linux/pagemap.h>
 
 #include <asm/tlbflush.h>
 #include <asm/cacheflush.h>
diff --git a/arch/csky/abiv1/cacheflush.c b/arch/csky/abiv1/cacheflush.c
index 9f1fe80cc847..07ff17ea33de 100644
--- a/arch/csky/abiv1/cacheflush.c
+++ b/arch/csky/abiv1/cacheflush.c
@@ -4,6 +4,7 @@
 #include <linux/kernel.h>
 #include <linux/mm.h>
 #include <linux/fs.h>
+#include <linux/pagemap.h>
 #include <linux/syscalls.h>
 #include <linux/spinlock.h>
 #include <asm/page.h>
diff --git a/arch/mips/mm/cache.c b/arch/mips/mm/cache.c
index 7719d632df8d..a7bf0c80371c 100644
--- a/arch/mips/mm/cache.c
+++ b/arch/mips/mm/cache.c
@@ -15,6 +15,7 @@
 #include <linux/syscalls.h>
 #include <linux/mm.h>
 #include <linux/highmem.h>
+#include <linux/pagemap.h>
 
 #include <asm/cacheflush.h>
 #include <asm/processor.h>
diff --git a/arch/nios2/mm/cacheflush.c b/arch/nios2/mm/cacheflush.c
index 65de1bd6a760..6aa9257c3ede 100644
--- a/arch/nios2/mm/cacheflush.c
+++ b/arch/nios2/mm/cacheflush.c
@@ -11,6 +11,7 @@
 #include <linux/sched.h>
 #include <linux/mm.h>
 #include <linux/fs.h>
+#include <linux/pagemap.h>
 
 #include <asm/cacheflush.h>
 #include <asm/cpuinfo.h>
diff --git a/arch/sh/mm/cache-sh4.c b/arch/sh/mm/cache-sh4.c
index ddfa9685f1ef..72c2e1b46c08 100644
--- a/arch/sh/mm/cache-sh4.c
+++ b/arch/sh/mm/cache-sh4.c
@@ -16,6 +16,7 @@
 #include <linux/mutex.h>
 #include <linux/fs.h>
 #include <linux/highmem.h>
+#include <linux/pagemap.h>
 #include <asm/mmu_context.h>
 #include <asm/cache_insns.h>
 #include <asm/cacheflush.h>
diff --git a/arch/sh/mm/cache-sh7705.c b/arch/sh/mm/cache-sh7705.c
index 4c67b3d88775..9b63a53a5e46 100644
--- a/arch/sh/mm/cache-sh7705.c
+++ b/arch/sh/mm/cache-sh7705.c
@@ -13,6 +13,7 @@
 #include <linux/mman.h>
 #include <linux/mm.h>
 #include <linux/fs.h>
+#include <linux/pagemap.h>
 #include <linux/threads.h>
 #include <asm/addrspace.h>
 #include <asm/page.h>
diff --git a/arch/sparc/mm/tlb.c b/arch/sparc/mm/tlb.c
index 20ee14739333..9a725547578e 100644
--- a/arch/sparc/mm/tlb.c
+++ b/arch/sparc/mm/tlb.c
@@ -9,6 +9,7 @@
 #include <linux/mm.h>
 #include <linux/swap.h>
 #include <linux/preempt.h>
+#include <linux/pagemap.h>
 
 #include <asm/tlbflush.h>
 #include <asm/cacheflush.h>
diff --git a/include/linux/mm.h b/include/linux/mm.h
index fbe0843daa90..f69a72f63e44 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1645,7 +1645,6 @@ static inline pgoff_t page_index(struct page *page)
 
 bool page_mapped(struct page *page);
 struct address_space *page_mapping(struct page *page);
-struct address_space *page_mapping_file(struct page *page);
 
 /*
  * Return true only if the page has been allocated with
diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index 08fa117f405c..f68fe61c1dec 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -162,6 +162,16 @@ static inline void filemap_nr_thps_dec(struct address_space *mapping)
 
 void release_pages(struct page **pages, int nr);
 
+/*
+ * For file cache pages, return the address_space, otherwise return NULL
+ */
+static inline struct address_space *page_mapping_file(struct page *page)
+{
+	if (unlikely(PageSwapCache(page)))
+		return NULL;
+	return page_mapping(page);
+}
+
 /*
  * speculatively take a reference to a page.
  * If the page is free (_refcount == 0), then _refcount is untouched, and 0
diff --git a/mm/util.c b/mm/util.c
index 143c627fb3e8..972e7a0cda5e 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -711,16 +711,6 @@ struct address_space *page_mapping(struct page *page)
 }
 EXPORT_SYMBOL(page_mapping);
 
-/*
- * For file cache pages, return the address_space, otherwise return NULL
- */
-struct address_space *page_mapping_file(struct page *page)
-{
-	if (unlikely(PageSwapCache(page)))
-		return NULL;
-	return page_mapping(page);
-}
-
 /* Slow path of page_mapcount() for compound pages */
 int __page_mapcount(struct page *page)
 {
-- 
2.30.1