Linux kernel mirror (for testing)
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1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef __SHMEM_FS_H
3#define __SHMEM_FS_H
4
5#include <linux/file.h>
6#include <linux/swap.h>
7#include <linux/mempolicy.h>
8#include <linux/pagemap.h>
9#include <linux/percpu_counter.h>
10#include <linux/xattr.h>
11#include <linux/fs_parser.h>
12
13/* inode in-kernel data */
14
15struct shmem_inode_info {
16 spinlock_t lock;
17 unsigned int seals; /* shmem seals */
18 unsigned long flags;
19 unsigned long alloced; /* data pages alloced to file */
20 unsigned long swapped; /* subtotal assigned to swap */
21 struct list_head shrinklist; /* shrinkable hpage inodes */
22 struct list_head swaplist; /* chain of maybes on swap */
23 struct shared_policy policy; /* NUMA memory alloc policy */
24 struct simple_xattrs xattrs; /* list of xattrs */
25 atomic_t stop_eviction; /* hold when working on inode */
26 struct inode vfs_inode;
27};
28
29struct shmem_sb_info {
30 unsigned long max_blocks; /* How many blocks are allowed */
31 struct percpu_counter used_blocks; /* How many are allocated */
32 unsigned long max_inodes; /* How many inodes are allowed */
33 unsigned long free_inodes; /* How many are left for allocation */
34 spinlock_t stat_lock; /* Serialize shmem_sb_info changes */
35 umode_t mode; /* Mount mode for root directory */
36 unsigned char huge; /* Whether to try for hugepages */
37 kuid_t uid; /* Mount uid for root directory */
38 kgid_t gid; /* Mount gid for root directory */
39 struct mempolicy *mpol; /* default memory policy for mappings */
40 spinlock_t shrinklist_lock; /* Protects shrinklist */
41 struct list_head shrinklist; /* List of shinkable inodes */
42 unsigned long shrinklist_len; /* Length of shrinklist */
43};
44
45static inline struct shmem_inode_info *SHMEM_I(struct inode *inode)
46{
47 return container_of(inode, struct shmem_inode_info, vfs_inode);
48}
49
50/*
51 * Functions in mm/shmem.c called directly from elsewhere:
52 */
53extern const struct fs_parameter_spec shmem_fs_parameters[];
54extern int shmem_init(void);
55extern int shmem_init_fs_context(struct fs_context *fc);
56extern struct file *shmem_file_setup(const char *name,
57 loff_t size, unsigned long flags);
58extern struct file *shmem_kernel_file_setup(const char *name, loff_t size,
59 unsigned long flags);
60extern struct file *shmem_file_setup_with_mnt(struct vfsmount *mnt,
61 const char *name, loff_t size, unsigned long flags);
62extern int shmem_zero_setup(struct vm_area_struct *);
63extern unsigned long shmem_get_unmapped_area(struct file *, unsigned long addr,
64 unsigned long len, unsigned long pgoff, unsigned long flags);
65extern int shmem_lock(struct file *file, int lock, struct user_struct *user);
66#ifdef CONFIG_SHMEM
67extern bool shmem_mapping(struct address_space *mapping);
68#else
69static inline bool shmem_mapping(struct address_space *mapping)
70{
71 return false;
72}
73#endif /* CONFIG_SHMEM */
74extern void shmem_unlock_mapping(struct address_space *mapping);
75extern struct page *shmem_read_mapping_page_gfp(struct address_space *mapping,
76 pgoff_t index, gfp_t gfp_mask);
77extern void shmem_truncate_range(struct inode *inode, loff_t start, loff_t end);
78extern int shmem_unuse(unsigned int type, bool frontswap,
79 unsigned long *fs_pages_to_unuse);
80
81extern unsigned long shmem_swap_usage(struct vm_area_struct *vma);
82extern unsigned long shmem_partial_swap_usage(struct address_space *mapping,
83 pgoff_t start, pgoff_t end);
84
85/* Flag allocation requirements to shmem_getpage */
86enum sgp_type {
87 SGP_READ, /* don't exceed i_size, don't allocate page */
88 SGP_CACHE, /* don't exceed i_size, may allocate page */
89 SGP_NOHUGE, /* like SGP_CACHE, but no huge pages */
90 SGP_HUGE, /* like SGP_CACHE, huge pages preferred */
91 SGP_WRITE, /* may exceed i_size, may allocate !Uptodate page */
92 SGP_FALLOC, /* like SGP_WRITE, but make existing page Uptodate */
93};
94
95extern int shmem_getpage(struct inode *inode, pgoff_t index,
96 struct page **pagep, enum sgp_type sgp);
97
98static inline struct page *shmem_read_mapping_page(
99 struct address_space *mapping, pgoff_t index)
100{
101 return shmem_read_mapping_page_gfp(mapping, index,
102 mapping_gfp_mask(mapping));
103}
104
105static inline bool shmem_file(struct file *file)
106{
107 if (!IS_ENABLED(CONFIG_SHMEM))
108 return false;
109 if (!file || !file->f_mapping)
110 return false;
111 return shmem_mapping(file->f_mapping);
112}
113
114extern bool shmem_charge(struct inode *inode, long pages);
115extern void shmem_uncharge(struct inode *inode, long pages);
116
117#ifdef CONFIG_TRANSPARENT_HUGE_PAGECACHE
118extern bool shmem_huge_enabled(struct vm_area_struct *vma);
119#else
120static inline bool shmem_huge_enabled(struct vm_area_struct *vma)
121{
122 return false;
123}
124#endif
125
126#ifdef CONFIG_SHMEM
127extern int shmem_mcopy_atomic_pte(struct mm_struct *dst_mm, pmd_t *dst_pmd,
128 struct vm_area_struct *dst_vma,
129 unsigned long dst_addr,
130 unsigned long src_addr,
131 struct page **pagep);
132extern int shmem_mfill_zeropage_pte(struct mm_struct *dst_mm,
133 pmd_t *dst_pmd,
134 struct vm_area_struct *dst_vma,
135 unsigned long dst_addr);
136#else
137#define shmem_mcopy_atomic_pte(dst_mm, dst_pte, dst_vma, dst_addr, \
138 src_addr, pagep) ({ BUG(); 0; })
139#define shmem_mfill_zeropage_pte(dst_mm, dst_pmd, dst_vma, \
140 dst_addr) ({ BUG(); 0; })
141#endif
142
143#endif