mm: move shmem prototypes to shmem_fs.h

Before adding any more global entry points into shmem.c, gather such
prototypes into shmem_fs.h.  Remove mm's own declarations from swap.h,
but for now leave the ones in mm.h: because shmem_file_setup() and
shmem_zero_setup() are called from various places, and we should not
force other subsystems to update immediately.

Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/linux/shmem_fs.h

@@ -5,6 +5,13 @@
 #include <linux/mempolicy.h>
 #include <linux/percpu_counter.h>
 
+struct page;
+struct file;
+struct inode;
+struct super_block;
+struct user_struct;
+struct vm_area_struct;
+
 /* inode in-kernel data */
 
 #define SHMEM_NR_DIRECT 16
@@ -45,7 +52,17 @@ static inline struct shmem_inode_info *SHMEM_I(struct inode *inode)
 	return container_of(inode, struct shmem_inode_info, vfs_inode);
 }
 
+/*
+ * Functions in mm/shmem.c called directly from elsewhere:
+ */
 extern int init_tmpfs(void);
 extern int shmem_fill_super(struct super_block *sb, void *data, int silent);
+extern struct file *shmem_file_setup(const char *name,
+					loff_t size, unsigned long flags);
+extern int shmem_zero_setup(struct vm_area_struct *);
+extern int shmem_lock(struct file *file, int lock, struct user_struct *user);
+extern int shmem_unuse(swp_entry_t entry, struct page *page);
+extern void mem_cgroup_get_shmem_target(struct inode *inode, pgoff_t pgoff,
+					struct page **pagep, swp_entry_t *ent);
 
 #endif

include/linux/swap.h

@@ -300,16 +300,6 @@ static inline void scan_unevictable_unregister_node(struct node *node)
 extern int kswapd_run(int nid);
 extern void kswapd_stop(int nid);
 
-#ifdef CONFIG_MMU
-/* linux/mm/shmem.c */
-extern int shmem_unuse(swp_entry_t entry, struct page *page);
-#endif /* CONFIG_MMU */
-
-#ifdef CONFIG_CGROUP_MEM_RES_CTLR
-extern void mem_cgroup_get_shmem_target(struct inode *inode, pgoff_t pgoff,
-					struct page **pagep, swp_entry_t *ent);
-#endif
-
 #ifdef CONFIG_SWAP
 /* linux/mm/page_io.c */
 extern int swap_readpage(struct page *);

mm/memcontrol.c

@@ -35,6 +35,7 @@
 #include <linux/limits.h>
 #include <linux/mutex.h>
 #include <linux/rbtree.h>
+#include <linux/shmem_fs.h>
 #include <linux/slab.h>
 #include <linux/swap.h>
 #include <linux/swapops.h>

mm/swapfile.c

@@ -14,7 +14,7 @@
 #include <linux/vmalloc.h>
 #include <linux/pagemap.h>
 #include <linux/namei.h>
-#include <linux/shm.h>
+#include <linux/shmem_fs.h>
 #include <linux/blkdev.h>
 #include <linux/random.h>
 #include <linux/writeback.h>