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
SHMEM_I(struct inode * inode)48 static inline struct shmem_inode_info *SHMEM_I(struct inode *inode)
49 {
50 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 bool shmem_mapping(struct address_space *mapping);
71 #else
shmem_mapping(struct address_space * mapping)72 static inline bool shmem_mapping(struct address_space *mapping)
73 {
74 return false;
75 }
76 #endif /* CONFIG_SHMEM */
77 extern void shmem_unlock_mapping(struct address_space *mapping);
78 extern struct page *shmem_read_mapping_page_gfp(struct address_space *mapping,
79 pgoff_t index, gfp_t gfp_mask);
80 extern void shmem_truncate_range(struct inode *inode, loff_t start, loff_t end);
81 extern int shmem_unuse(unsigned int type, bool frontswap,
82 unsigned long *fs_pages_to_unuse);
83
84 extern bool shmem_huge_enabled(struct vm_area_struct *vma);
85 extern unsigned long shmem_swap_usage(struct vm_area_struct *vma);
86 extern unsigned long shmem_partial_swap_usage(struct address_space *mapping,
87 pgoff_t start, pgoff_t end);
88 extern void shmem_mark_page_lazyfree(struct page *page, bool tail);
89
90 /* Flag allocation requirements to shmem_getpage */
91 enum sgp_type {
92 SGP_READ, /* don't exceed i_size, don't allocate page */
93 SGP_CACHE, /* don't exceed i_size, may allocate page */
94 SGP_NOHUGE, /* like SGP_CACHE, but no huge pages */
95 SGP_HUGE, /* like SGP_CACHE, huge pages preferred */
96 SGP_WRITE, /* may exceed i_size, may allocate !Uptodate page */
97 SGP_FALLOC, /* like SGP_WRITE, but make existing page Uptodate */
98 };
99
100 extern int shmem_getpage(struct inode *inode, pgoff_t index,
101 struct page **pagep, enum sgp_type sgp);
102
shmem_read_mapping_page(struct address_space * mapping,pgoff_t index)103 static inline struct page *shmem_read_mapping_page(
104 struct address_space *mapping, pgoff_t index)
105 {
106 return shmem_read_mapping_page_gfp(mapping, index,
107 mapping_gfp_mask(mapping));
108 }
109
shmem_file(struct file * file)110 static inline bool shmem_file(struct file *file)
111 {
112 if (!IS_ENABLED(CONFIG_SHMEM))
113 return false;
114 if (!file || !file->f_mapping)
115 return false;
116 return shmem_mapping(file->f_mapping);
117 }
118
119 extern bool shmem_charge(struct inode *inode, long pages);
120 extern void shmem_uncharge(struct inode *inode, long pages);
121
122 #ifdef CONFIG_USERFAULTFD
123 #ifdef CONFIG_SHMEM
124 extern int shmem_mfill_atomic_pte(struct mm_struct *dst_mm, pmd_t *dst_pmd,
125 struct vm_area_struct *dst_vma,
126 unsigned long dst_addr,
127 unsigned long src_addr,
128 bool zeropage,
129 struct page **pagep);
130 #else /* !CONFIG_SHMEM */
131 #define shmem_mfill_atomic_pte(dst_mm, dst_pmd, dst_vma, dst_addr, \
132 src_addr, zeropage, pagep) ({ BUG(); 0; })
133 #endif /* CONFIG_SHMEM */
134 #endif /* CONFIG_USERFAULTFD */
135
136 #endif
137