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 unsigned int fsflags; /* flags for FS_IOC_[SG]ETFLAGS */
29 struct inode vfs_inode;
30 };
31
32 #define SHMEM_FL_USER_VISIBLE FS_FL_USER_VISIBLE
33 #define SHMEM_FL_USER_MODIFIABLE \
34 (FS_IMMUTABLE_FL | FS_APPEND_FL | FS_NODUMP_FL | FS_NOATIME_FL)
35 #define SHMEM_FL_INHERITED (FS_NODUMP_FL | FS_NOATIME_FL)
36
37 struct shmem_sb_info {
38 unsigned long max_blocks; /* How many blocks are allowed */
39 struct percpu_counter used_blocks; /* How many are allocated */
40 unsigned long max_inodes; /* How many inodes are allowed */
41 unsigned long free_inodes; /* How many are left for allocation */
42 raw_spinlock_t stat_lock; /* Serialize shmem_sb_info changes */
43 umode_t mode; /* Mount mode for root directory */
44 unsigned char huge; /* Whether to try for hugepages */
45 kuid_t uid; /* Mount uid for root directory */
46 kgid_t gid; /* Mount gid for root directory */
47 bool full_inums; /* If i_ino should be uint or ino_t */
48 ino_t next_ino; /* The next per-sb inode number to use */
49 ino_t __percpu *ino_batch; /* The next per-cpu inode number to use */
50 struct mempolicy *mpol; /* default memory policy for mappings */
51 spinlock_t shrinklist_lock; /* Protects shrinklist */
52 struct list_head shrinklist; /* List of shinkable inodes */
53 unsigned long shrinklist_len; /* Length of shrinklist */
54 };
55
SHMEM_I(struct inode * inode)56 static inline struct shmem_inode_info *SHMEM_I(struct inode *inode)
57 {
58 return container_of(inode, struct shmem_inode_info, vfs_inode);
59 }
60
61 /*
62 * Functions in mm/shmem.c called directly from elsewhere:
63 */
64 extern const struct fs_parameter_spec shmem_fs_parameters[];
65 extern void shmem_init(void);
66 extern int shmem_init_fs_context(struct fs_context *fc);
67 extern struct file *shmem_file_setup(const char *name,
68 loff_t size, unsigned long flags);
69 extern struct file *shmem_kernel_file_setup(const char *name, loff_t size,
70 unsigned long flags);
71 extern struct file *shmem_file_setup_with_mnt(struct vfsmount *mnt,
72 const char *name, loff_t size, unsigned long flags);
73 extern int shmem_zero_setup(struct vm_area_struct *);
74 extern unsigned long shmem_get_unmapped_area(struct file *, unsigned long addr,
75 unsigned long len, unsigned long pgoff, unsigned long flags);
76 extern int shmem_lock(struct file *file, int lock, struct ucounts *ucounts);
77 #ifdef CONFIG_SHMEM
78 extern const struct address_space_operations shmem_aops;
shmem_mapping(struct address_space * mapping)79 static inline bool shmem_mapping(struct address_space *mapping)
80 {
81 return mapping->a_ops == &shmem_aops;
82 }
83 #else
shmem_mapping(struct address_space * mapping)84 static inline bool shmem_mapping(struct address_space *mapping)
85 {
86 return false;
87 }
88 #endif /* CONFIG_SHMEM */
89 extern void shmem_unlock_mapping(struct address_space *mapping);
90 extern struct page *shmem_read_mapping_page_gfp(struct address_space *mapping,
91 pgoff_t index, gfp_t gfp_mask);
92 extern void shmem_truncate_range(struct inode *inode, loff_t start, loff_t end);
93 int shmem_unuse(unsigned int type);
94
95 extern bool shmem_is_huge(struct vm_area_struct *vma, struct inode *inode,
96 pgoff_t index, bool shmem_huge_force);
shmem_huge_enabled(struct vm_area_struct * vma,bool shmem_huge_force)97 static inline bool shmem_huge_enabled(struct vm_area_struct *vma,
98 bool shmem_huge_force)
99 {
100 return shmem_is_huge(vma, file_inode(vma->vm_file), vma->vm_pgoff,
101 shmem_huge_force);
102 }
103 extern unsigned long shmem_swap_usage(struct vm_area_struct *vma);
104 extern unsigned long shmem_partial_swap_usage(struct address_space *mapping,
105 pgoff_t start, pgoff_t end);
106
107 /* Flag allocation requirements to shmem_get_folio */
108 enum sgp_type {
109 SGP_READ, /* don't exceed i_size, don't allocate page */
110 SGP_NOALLOC, /* similar, but fail on hole or use fallocated page */
111 SGP_CACHE, /* don't exceed i_size, may allocate page */
112 SGP_WRITE, /* may exceed i_size, may allocate !Uptodate page */
113 SGP_FALLOC, /* like SGP_WRITE, but make existing page Uptodate */
114 };
115
116 int shmem_get_folio(struct inode *inode, pgoff_t index, struct folio **foliop,
117 enum sgp_type sgp);
118
shmem_read_mapping_page(struct address_space * mapping,pgoff_t index)119 static inline struct page *shmem_read_mapping_page(
120 struct address_space *mapping, pgoff_t index)
121 {
122 return shmem_read_mapping_page_gfp(mapping, index,
123 mapping_gfp_mask(mapping));
124 }
125
shmem_file(struct file * file)126 static inline bool shmem_file(struct file *file)
127 {
128 if (!IS_ENABLED(CONFIG_SHMEM))
129 return false;
130 if (!file || !file->f_mapping)
131 return false;
132 return shmem_mapping(file->f_mapping);
133 }
134
135 /*
136 * If fallocate(FALLOC_FL_KEEP_SIZE) has been used, there may be pages
137 * beyond i_size's notion of EOF, which fallocate has committed to reserving:
138 * which split_huge_page() must therefore not delete. This use of a single
139 * "fallocend" per inode errs on the side of not deleting a reservation when
140 * in doubt: there are plenty of cases when it preserves unreserved pages.
141 */
shmem_fallocend(struct inode * inode,pgoff_t eof)142 static inline pgoff_t shmem_fallocend(struct inode *inode, pgoff_t eof)
143 {
144 return max(eof, SHMEM_I(inode)->fallocend);
145 }
146
147 extern bool shmem_charge(struct inode *inode, long pages);
148 extern void shmem_uncharge(struct inode *inode, long pages);
149
150 #ifdef CONFIG_USERFAULTFD
151 #ifdef CONFIG_SHMEM
152 extern int shmem_mfill_atomic_pte(struct mm_struct *dst_mm, pmd_t *dst_pmd,
153 struct vm_area_struct *dst_vma,
154 unsigned long dst_addr,
155 unsigned long src_addr,
156 bool zeropage, bool wp_copy,
157 struct page **pagep);
158 #else /* !CONFIG_SHMEM */
159 #define shmem_mfill_atomic_pte(dst_mm, dst_pmd, dst_vma, dst_addr, \
160 src_addr, zeropage, wp_copy, pagep) ({ BUG(); 0; })
161 #endif /* CONFIG_SHMEM */
162 #endif /* CONFIG_USERFAULTFD */
163
164 #endif
165