Branch data 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 : :
12 : : /* inode in-kernel data */
13 : :
14 : : struct shmem_inode_info {
15 : : spinlock_t lock;
16 : : unsigned int seals; /* shmem seals */
17 : : unsigned long flags;
18 : : unsigned long alloced; /* data pages alloced to file */
19 : : unsigned long swapped; /* subtotal assigned to swap */
20 : : struct list_head shrinklist; /* shrinkable hpage inodes */
21 : : struct list_head swaplist; /* chain of maybes on swap */
22 : : struct shared_policy policy; /* NUMA memory alloc policy */
23 : : struct simple_xattrs xattrs; /* list of xattrs */
24 : : atomic_t stop_eviction; /* hold when working on inode */
25 : : struct inode vfs_inode;
26 : : };
27 : :
28 : : struct 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 : : umode_t mode; /* Mount mode for root directory */
35 : : unsigned char huge; /* Whether to try for hugepages */
36 : : kuid_t uid; /* Mount uid for root directory */
37 : : kgid_t gid; /* Mount gid for root directory */
38 : : struct mempolicy *mpol; /* default memory policy for mappings */
39 : : spinlock_t shrinklist_lock; /* Protects shrinklist */
40 : : struct list_head shrinklist; /* List of shinkable inodes */
41 : : unsigned long shrinklist_len; /* Length of shrinklist */
42 : : };
43 : :
44 : : static inline struct shmem_inode_info *SHMEM_I(struct inode *inode)
45 : : {
46 : 1457276 : return container_of(inode, struct shmem_inode_info, vfs_inode);
47 : : }
48 : :
49 : : /*
50 : : * Functions in mm/shmem.c called directly from elsewhere:
51 : : */
52 : : extern const struct fs_parameter_description shmem_fs_parameters;
53 : : extern int shmem_init(void);
54 : : extern int shmem_init_fs_context(struct fs_context *fc);
55 : : extern struct file *shmem_file_setup(const char *name,
56 : : loff_t size, unsigned long flags);
57 : : extern struct file *shmem_kernel_file_setup(const char *name, loff_t size,
58 : : unsigned long flags);
59 : : extern struct file *shmem_file_setup_with_mnt(struct vfsmount *mnt,
60 : : const char *name, loff_t size, unsigned long flags);
61 : : extern int shmem_zero_setup(struct vm_area_struct *);
62 : : extern unsigned long shmem_get_unmapped_area(struct file *, unsigned long addr,
63 : : unsigned long len, unsigned long pgoff, unsigned long flags);
64 : : extern int shmem_lock(struct file *file, int lock, struct user_struct *user);
65 : : #ifdef CONFIG_SHMEM
66 : : extern bool shmem_mapping(struct address_space *mapping);
67 : : #else
68 : : static inline bool shmem_mapping(struct address_space *mapping)
69 : : {
70 : : return false;
71 : : }
72 : : #endif /* CONFIG_SHMEM */
73 : : extern void shmem_unlock_mapping(struct address_space *mapping);
74 : : extern struct page *shmem_read_mapping_page_gfp(struct address_space *mapping,
75 : : pgoff_t index, gfp_t gfp_mask);
76 : : extern void shmem_truncate_range(struct inode *inode, loff_t start, loff_t end);
77 : : extern int shmem_unuse(unsigned int type, bool frontswap,
78 : : unsigned long *fs_pages_to_unuse);
79 : :
80 : : extern unsigned long shmem_swap_usage(struct vm_area_struct *vma);
81 : : extern unsigned long shmem_partial_swap_usage(struct address_space *mapping,
82 : : pgoff_t start, pgoff_t end);
83 : :
84 : : /* Flag allocation requirements to shmem_getpage */
85 : : enum sgp_type {
86 : : SGP_READ, /* don't exceed i_size, don't allocate page */
87 : : SGP_CACHE, /* don't exceed i_size, may allocate page */
88 : : SGP_NOHUGE, /* like SGP_CACHE, but no huge pages */
89 : : SGP_HUGE, /* like SGP_CACHE, huge pages preferred */
90 : : SGP_WRITE, /* may exceed i_size, may allocate !Uptodate page */
91 : : SGP_FALLOC, /* like SGP_WRITE, but make existing page Uptodate */
92 : : };
93 : :
94 : : extern int shmem_getpage(struct inode *inode, pgoff_t index,
95 : : struct page **pagep, enum sgp_type sgp);
96 : :
97 : : static inline struct page *shmem_read_mapping_page(
98 : : struct address_space *mapping, pgoff_t index)
99 : : {
100 : : return shmem_read_mapping_page_gfp(mapping, index,
101 : : mapping_gfp_mask(mapping));
102 : : }
103 : :
104 : : static inline bool shmem_file(struct file *file)
105 : : {
106 : : if (!IS_ENABLED(CONFIG_SHMEM))
107 : : return false;
108 [ + - + - ]: 2 : if (!file || !file->f_mapping)
109 : : return false;
110 : 2 : return shmem_mapping(file->f_mapping);
111 : : }
112 : :
113 : : extern bool shmem_charge(struct inode *inode, long pages);
114 : : extern void shmem_uncharge(struct inode *inode, long pages);
115 : :
116 : : #ifdef CONFIG_TRANSPARENT_HUGE_PAGECACHE
117 : : extern bool shmem_huge_enabled(struct vm_area_struct *vma);
118 : : #else
119 : : static inline bool shmem_huge_enabled(struct vm_area_struct *vma)
120 : : {
121 : : return false;
122 : : }
123 : : #endif
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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