Line data Source code
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 :
15 : struct 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 :
29 : struct 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 : bool full_inums; /* If i_ino should be uint or ino_t */
40 : ino_t next_ino; /* The next per-sb inode number to use */
41 : ino_t __percpu *ino_batch; /* The next per-cpu inode number to use */
42 : struct mempolicy *mpol; /* default memory policy for mappings */
43 : spinlock_t shrinklist_lock; /* Protects shrinklist */
44 : struct list_head shrinklist; /* List of shinkable inodes */
45 : unsigned long shrinklist_len; /* Length of shrinklist */
46 : };
47 :
48 16143 : static inline struct shmem_inode_info *SHMEM_I(struct inode *inode)
49 : {
50 16143 : return container_of(inode, struct shmem_inode_info, vfs_inode);
51 : }
52 :
53 : /*
54 : * Functions in mm/shmem.c called directly from elsewhere:
55 : */
56 : extern const struct fs_parameter_spec shmem_fs_parameters[];
57 : extern int shmem_init(void);
58 : extern int shmem_init_fs_context(struct fs_context *fc);
59 : extern struct file *shmem_file_setup(const char *name,
60 : loff_t size, unsigned long flags);
61 : extern struct file *shmem_kernel_file_setup(const char *name, loff_t size,
62 : unsigned long flags);
63 : extern struct file *shmem_file_setup_with_mnt(struct vfsmount *mnt,
64 : const char *name, loff_t size, unsigned long flags);
65 : extern int shmem_zero_setup(struct vm_area_struct *);
66 : extern unsigned long shmem_get_unmapped_area(struct file *, unsigned long addr,
67 : unsigned long len, unsigned long pgoff, unsigned long flags);
68 : extern int shmem_lock(struct file *file, int lock, struct user_struct *user);
69 : #ifdef CONFIG_SHMEM
70 : extern const struct address_space_operations shmem_aops;
71 6885 : static inline bool shmem_mapping(struct address_space *mapping)
72 : {
73 6885 : return mapping->a_ops == &shmem_aops;
74 : }
75 : #else
76 : static inline bool shmem_mapping(struct address_space *mapping)
77 : {
78 : return false;
79 : }
80 : #endif /* CONFIG_SHMEM */
81 : extern void shmem_unlock_mapping(struct address_space *mapping);
82 : extern struct page *shmem_read_mapping_page_gfp(struct address_space *mapping,
83 : pgoff_t index, gfp_t gfp_mask);
84 : extern void shmem_truncate_range(struct inode *inode, loff_t start, loff_t end);
85 : extern int shmem_unuse(unsigned int type, bool frontswap,
86 : unsigned long *fs_pages_to_unuse);
87 :
88 : extern bool shmem_huge_enabled(struct vm_area_struct *vma);
89 : extern unsigned long shmem_swap_usage(struct vm_area_struct *vma);
90 : extern unsigned long shmem_partial_swap_usage(struct address_space *mapping,
91 : pgoff_t start, pgoff_t end);
92 :
93 : /* Flag allocation requirements to shmem_getpage */
94 : enum sgp_type {
95 : SGP_READ, /* don't exceed i_size, don't allocate page */
96 : SGP_CACHE, /* don't exceed i_size, may allocate page */
97 : SGP_NOHUGE, /* like SGP_CACHE, but no huge pages */
98 : SGP_HUGE, /* like SGP_CACHE, huge pages preferred */
99 : SGP_WRITE, /* may exceed i_size, may allocate !Uptodate page */
100 : SGP_FALLOC, /* like SGP_WRITE, but make existing page Uptodate */
101 : };
102 :
103 : extern int shmem_getpage(struct inode *inode, pgoff_t index,
104 : struct page **pagep, enum sgp_type sgp);
105 :
106 : static inline struct page *shmem_read_mapping_page(
107 : struct address_space *mapping, pgoff_t index)
108 : {
109 : return shmem_read_mapping_page_gfp(mapping, index,
110 : mapping_gfp_mask(mapping));
111 : }
112 :
113 6330 : static inline bool shmem_file(struct file *file)
114 : {
115 6330 : if (!IS_ENABLED(CONFIG_SHMEM))
116 : return false;
117 6330 : if (!file || !file->f_mapping)
118 : return false;
119 3594 : return shmem_mapping(file->f_mapping);
120 : }
121 :
122 : extern bool shmem_charge(struct inode *inode, long pages);
123 : extern void shmem_uncharge(struct inode *inode, long pages);
124 :
125 : #ifdef CONFIG_SHMEM
126 : extern int shmem_mcopy_atomic_pte(struct mm_struct *dst_mm, pmd_t *dst_pmd,
127 : struct vm_area_struct *dst_vma,
128 : unsigned long dst_addr,
129 : unsigned long src_addr,
130 : struct page **pagep);
131 : extern int shmem_mfill_zeropage_pte(struct mm_struct *dst_mm,
132 : pmd_t *dst_pmd,
133 : struct vm_area_struct *dst_vma,
134 : unsigned long dst_addr);
135 : #else
136 : #define shmem_mcopy_atomic_pte(dst_mm, dst_pte, dst_vma, dst_addr, \
137 : src_addr, pagep) ({ BUG(); 0; })
138 : #define shmem_mfill_zeropage_pte(dst_mm, dst_pmd, dst_vma, \
139 : dst_addr) ({ BUG(); 0; })
140 : #endif
141 :
142 : #endif
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