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 pgoff_t fallocend; /* highest fallocate endindex */
22 struct list_head shrinklist; /* shrinkable hpage inodes */
23 struct list_head swaplist; /* chain of maybes on swap */
24 struct shared_policy policy; /* NUMA memory alloc policy */
25 struct simple_xattrs xattrs; /* list of xattrs */
26 atomic_t stop_eviction; /* hold when working on inode */
27 struct timespec64 i_crtime; /* file creation time */
28 struct inode vfs_inode;
29 };
30
31 struct shmem_sb_info {
32 unsigned long max_blocks; /* How many blocks are allowed */
33 struct percpu_counter used_blocks; /* How many are allocated */
34 unsigned long max_inodes; /* How many inodes are allowed */
35 unsigned long free_inodes; /* How many are left for allocation */
36 raw_spinlock_t stat_lock; /* Serialize shmem_sb_info changes */
37 umode_t mode; /* Mount mode for root directory */
38 unsigned char huge; /* Whether to try for hugepages */
39 kuid_t uid; /* Mount uid for root directory */
40 kgid_t gid; /* Mount gid for root directory */
41 bool full_inums; /* If i_ino should be uint or ino_t */
42 ino_t next_ino; /* The next per-sb inode number to use */
43 ino_t __percpu *ino_batch; /* The next per-cpu inode number to use */
44 struct mempolicy *mpol; /* default memory policy for mappings */
45 spinlock_t shrinklist_lock; /* Protects shrinklist */
46 struct list_head shrinklist; /* List of shinkable inodes */
47 unsigned long shrinklist_len; /* Length of shrinklist */
48 };
49
SHMEM_I(struct inode * inode)50 static inline struct shmem_inode_info *SHMEM_I(struct inode *inode)
51 {
52 return container_of(inode, struct shmem_inode_info, vfs_inode);
53 }
54
55 /*
56 * Functions in mm/shmem.c called directly from elsewhere:
57 */
58 extern const struct fs_parameter_spec shmem_fs_parameters[];
59 extern void shmem_init(void);
60 extern int shmem_init_fs_context(struct fs_context *fc);
61 extern struct file *shmem_file_setup(const char *name,
62 loff_t size, unsigned long flags);
63 extern struct file *shmem_kernel_file_setup(const char *name, loff_t size,
64 unsigned long flags);
65 extern struct file *shmem_file_setup_with_mnt(struct vfsmount *mnt,
66 const char *name, loff_t size, unsigned long flags);
67 extern int shmem_zero_setup(struct vm_area_struct *);
68 extern unsigned long shmem_get_unmapped_area(struct file *, unsigned long addr,
69 unsigned long len, unsigned long pgoff, unsigned long flags);
70 extern int shmem_lock(struct file *file, int lock, struct ucounts *ucounts);
71 #ifdef CONFIG_SHMEM
72 extern const struct address_space_operations shmem_aops;
shmem_mapping(struct address_space * mapping)73 static inline bool shmem_mapping(struct address_space *mapping)
74 {
75 return mapping->a_ops == &shmem_aops;
76 }
77 #else
shmem_mapping(struct address_space * mapping)78 static inline bool shmem_mapping(struct address_space *mapping)
79 {
80 return false;
81 }
82 #endif /* CONFIG_SHMEM */
83 extern void shmem_unlock_mapping(struct address_space *mapping);
84 extern struct page *shmem_read_mapping_page_gfp(struct address_space *mapping,
85 pgoff_t index, gfp_t gfp_mask);
86 extern void shmem_truncate_range(struct inode *inode, loff_t start, loff_t end);
87 int shmem_unuse(unsigned int type);
88
89 extern bool shmem_is_huge(struct vm_area_struct *vma,
90 struct inode *inode, pgoff_t index);
shmem_huge_enabled(struct vm_area_struct * vma)91 static inline bool shmem_huge_enabled(struct vm_area_struct *vma)
92 {
93 return shmem_is_huge(vma, file_inode(vma->vm_file), vma->vm_pgoff);
94 }
95 extern unsigned long shmem_swap_usage(struct vm_area_struct *vma);
96 extern unsigned long shmem_partial_swap_usage(struct address_space *mapping,
97 pgoff_t start, pgoff_t end);
98
99 /* Flag allocation requirements to shmem_getpage */
100 enum sgp_type {
101 SGP_READ, /* don't exceed i_size, don't allocate page */
102 SGP_NOALLOC, /* similar, but fail on hole or use fallocated page */
103 SGP_CACHE, /* don't exceed i_size, may allocate page */
104 SGP_WRITE, /* may exceed i_size, may allocate !Uptodate page */
105 SGP_FALLOC, /* like SGP_WRITE, but make existing page Uptodate */
106 };
107
108 extern int shmem_getpage(struct inode *inode, pgoff_t index,
109 struct page **pagep, enum sgp_type sgp);
110
shmem_read_mapping_page(struct address_space * mapping,pgoff_t index)111 static inline struct page *shmem_read_mapping_page(
112 struct address_space *mapping, pgoff_t index)
113 {
114 return shmem_read_mapping_page_gfp(mapping, index,
115 mapping_gfp_mask(mapping));
116 }
117
shmem_file(struct file * file)118 static inline bool shmem_file(struct file *file)
119 {
120 if (!IS_ENABLED(CONFIG_SHMEM))
121 return false;
122 if (!file || !file->f_mapping)
123 return false;
124 return shmem_mapping(file->f_mapping);
125 }
126
127 /*
128 * If fallocate(FALLOC_FL_KEEP_SIZE) has been used, there may be pages
129 * beyond i_size's notion of EOF, which fallocate has committed to reserving:
130 * which split_huge_page() must therefore not delete. This use of a single
131 * "fallocend" per inode errs on the side of not deleting a reservation when
132 * in doubt: there are plenty of cases when it preserves unreserved pages.
133 */
shmem_fallocend(struct inode * inode,pgoff_t eof)134 static inline pgoff_t shmem_fallocend(struct inode *inode, pgoff_t eof)
135 {
136 return max(eof, SHMEM_I(inode)->fallocend);
137 }
138
139 extern bool shmem_charge(struct inode *inode, long pages);
140 extern void shmem_uncharge(struct inode *inode, long pages);
141
142 #ifdef CONFIG_USERFAULTFD
143 #ifdef CONFIG_SHMEM
144 extern int shmem_mfill_atomic_pte(struct mm_struct *dst_mm, pmd_t *dst_pmd,
145 struct vm_area_struct *dst_vma,
146 unsigned long dst_addr,
147 unsigned long src_addr,
148 bool zeropage, bool wp_copy,
149 struct page **pagep);
150 #else /* !CONFIG_SHMEM */
151 #define shmem_mfill_atomic_pte(dst_mm, dst_pmd, dst_vma, dst_addr, \
152 src_addr, zeropage, wp_copy, pagep) ({ BUG(); 0; })
153 #endif /* CONFIG_SHMEM */
154 #endif /* CONFIG_USERFAULTFD */
155
156 #endif
157