1#ifndef __SHMEM_FS_H
2#define __SHMEM_FS_H
3
4#include <linux/file.h>
5#include <linux/swap.h>
6#include <linux/mempolicy.h>
7#include <linux/pagemap.h>
8#include <linux/percpu_counter.h>
9#include <linux/xattr.h>
10
11/* inode in-kernel data */
12
13struct shmem_inode_info {
14	spinlock_t		lock;
15	unsigned int		seals;		/* shmem seals */
16	unsigned long		flags;
17	unsigned long		alloced;	/* data pages alloced to file */
18	union {
19		unsigned long	swapped;	/* subtotal assigned to swap */
20		char		*symlink;	/* unswappable short symlink */
21	};
22	struct shared_policy	policy;		/* NUMA memory alloc policy */
23	struct list_head	swaplist;	/* chain of maybes on swap */
24	struct simple_xattrs	xattrs;		/* list of xattrs */
25	struct inode		vfs_inode;
26};
27
28struct shmem_sb_info {
29	unsigned long max_blocks;   /* How many blocks are allowed */
30	struct percpu_counter used_blocks;  /* How many are allocated */
31	unsigned long max_inodes;   /* How many inodes are allowed */
32	unsigned long free_inodes;  /* How many are left for allocation */
33	spinlock_t stat_lock;	    /* Serialize shmem_sb_info changes */
34	kuid_t uid;		    /* Mount uid for root directory */
35	kgid_t gid;		    /* Mount gid for root directory */
36	umode_t mode;		    /* Mount mode for root directory */
37	struct mempolicy *mpol;     /* default memory policy for mappings */
38};
39
40static inline struct shmem_inode_info *SHMEM_I(struct inode *inode)
41{
42	return container_of(inode, struct shmem_inode_info, vfs_inode);
43}
44
45/*
46 * Functions in mm/shmem.c called directly from elsewhere:
47 */
48extern int shmem_init(void);
49extern int shmem_fill_super(struct super_block *sb, void *data, int silent);
50extern struct file *shmem_file_setup(const char *name,
51					loff_t size, unsigned long flags);
52extern struct file *shmem_kernel_file_setup(const char *name, loff_t size,
53					    unsigned long flags);
54extern int shmem_zero_setup(struct vm_area_struct *);
55extern int shmem_lock(struct file *file, int lock, struct user_struct *user);
56extern bool shmem_mapping(struct address_space *mapping);
57extern void shmem_unlock_mapping(struct address_space *mapping);
58extern struct page *shmem_read_mapping_page_gfp(struct address_space *mapping,
59					pgoff_t index, gfp_t gfp_mask);
60extern void shmem_truncate_range(struct inode *inode, loff_t start, loff_t end);
61extern int shmem_unuse(swp_entry_t entry, struct page *page);
62
63static inline struct page *shmem_read_mapping_page(
64				struct address_space *mapping, pgoff_t index)
65{
66	return shmem_read_mapping_page_gfp(mapping, index,
67					mapping_gfp_mask(mapping));
68}
69
70#ifdef CONFIG_TMPFS
71
72extern int shmem_add_seals(struct file *file, unsigned int seals);
73extern int shmem_get_seals(struct file *file);
74extern long shmem_fcntl(struct file *file, unsigned int cmd, unsigned long arg);
75
76#else
77
78static inline long shmem_fcntl(struct file *f, unsigned int c, unsigned long a)
79{
80	return -EINVAL;
81}
82
83#endif
84
85#endif
86