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 struct inode vfs_inode;
25 };
26
27 struct shmem_sb_info {
28 unsigned long max_blocks; /* How many blocks are allowed */
29 struct percpu_counter used_blocks; /* How many are allocated */
30 unsigned long max_inodes; /* How many inodes are allowed */
31 unsigned long free_inodes; /* How many are left for allocation */
32 spinlock_t stat_lock; /* Serialize shmem_sb_info changes */
33 umode_t mode; /* Mount mode for root directory */
34 unsigned char huge; /* Whether to try for hugepages */
35 kuid_t uid; /* Mount uid for root directory */
36 kgid_t gid; /* Mount gid for root directory */
37 struct mempolicy *mpol; /* default memory policy for mappings */
38 spinlock_t shrinklist_lock; /* Protects shrinklist */
39 struct list_head shrinklist; /* List of shinkable inodes */
40 unsigned long shrinklist_len; /* Length of shrinklist */
41 };
42
SHMEM_I(struct inode * inode)43 static inline struct shmem_inode_info *SHMEM_I(struct inode *inode)
44 {
45 return container_of(inode, struct shmem_inode_info, vfs_inode);
46 }
47
48 /*
49 * Functions in mm/shmem.c called directly from elsewhere:
50 */
51 extern int shmem_init(void);
52 extern int shmem_fill_super(struct super_block *sb, void *data, int silent);
53 extern struct file *shmem_file_setup(const char *name,
54 loff_t size, unsigned long flags);
55 extern struct file *shmem_kernel_file_setup(const char *name, loff_t size,
56 unsigned long flags);
57 extern struct file *shmem_file_setup_with_mnt(struct vfsmount *mnt,
58 const char *name, loff_t size, unsigned long flags);
59 extern int shmem_zero_setup(struct vm_area_struct *);
60 extern unsigned long shmem_get_unmapped_area(struct file *, unsigned long addr,
61 unsigned long len, unsigned long pgoff, unsigned long flags);
62 extern int shmem_lock(struct file *file, int lock, struct user_struct *user);
63 #ifdef CONFIG_SHMEM
64 extern bool shmem_mapping(struct address_space *mapping);
65 #else
shmem_mapping(struct address_space * mapping)66 static inline bool shmem_mapping(struct address_space *mapping)
67 {
68 return false;
69 }
70 #endif /* CONFIG_SHMEM */
71 extern void shmem_unlock_mapping(struct address_space *mapping);
72 extern struct page *shmem_read_mapping_page_gfp(struct address_space *mapping,
73 pgoff_t index, gfp_t gfp_mask);
74 extern void shmem_truncate_range(struct inode *inode, loff_t start, loff_t end);
75 extern int shmem_unuse(swp_entry_t entry, struct page *page);
76
77 extern unsigned long shmem_swap_usage(struct vm_area_struct *vma);
78 extern unsigned long shmem_partial_swap_usage(struct address_space *mapping,
79 pgoff_t start, pgoff_t end);
80
81 /* Flag allocation requirements to shmem_getpage */
82 enum sgp_type {
83 SGP_READ, /* don't exceed i_size, don't allocate page */
84 SGP_CACHE, /* don't exceed i_size, may allocate page */
85 SGP_NOHUGE, /* like SGP_CACHE, but no huge pages */
86 SGP_HUGE, /* like SGP_CACHE, huge pages preferred */
87 SGP_WRITE, /* may exceed i_size, may allocate !Uptodate page */
88 SGP_FALLOC, /* like SGP_WRITE, but make existing page Uptodate */
89 };
90
91 extern int shmem_getpage(struct inode *inode, pgoff_t index,
92 struct page **pagep, enum sgp_type sgp);
93
shmem_read_mapping_page(struct address_space * mapping,pgoff_t index)94 static inline struct page *shmem_read_mapping_page(
95 struct address_space *mapping, pgoff_t index)
96 {
97 return shmem_read_mapping_page_gfp(mapping, index,
98 mapping_gfp_mask(mapping));
99 }
100
shmem_file(struct file * file)101 static inline bool shmem_file(struct file *file)
102 {
103 if (!IS_ENABLED(CONFIG_SHMEM))
104 return false;
105 if (!file || !file->f_mapping)
106 return false;
107 return shmem_mapping(file->f_mapping);
108 }
109
110 extern bool shmem_charge(struct inode *inode, long pages);
111 extern void shmem_uncharge(struct inode *inode, long pages);
112
113 #ifdef CONFIG_TRANSPARENT_HUGE_PAGECACHE
114 extern bool shmem_huge_enabled(struct vm_area_struct *vma);
115 #else
shmem_huge_enabled(struct vm_area_struct * vma)116 static inline bool shmem_huge_enabled(struct vm_area_struct *vma)
117 {
118 return false;
119 }
120 #endif
121
122 #ifdef CONFIG_SHMEM
123 extern int shmem_mcopy_atomic_pte(struct mm_struct *dst_mm, pmd_t *dst_pmd,
124 struct vm_area_struct *dst_vma,
125 unsigned long dst_addr,
126 unsigned long src_addr,
127 struct page **pagep);
128 extern int shmem_mfill_zeropage_pte(struct mm_struct *dst_mm,
129 pmd_t *dst_pmd,
130 struct vm_area_struct *dst_vma,
131 unsigned long dst_addr);
132 #else
133 #define shmem_mcopy_atomic_pte(dst_mm, dst_pte, dst_vma, dst_addr, \
134 src_addr, pagep) ({ BUG(); 0; })
135 #define shmem_mfill_zeropage_pte(dst_mm, dst_pmd, dst_vma, \
136 dst_addr) ({ BUG(); 0; })
137 #endif
138
139 #endif
140