Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * Wrapper functions for accessing the file_struct fd array. | |
3 | */ | |
4 | ||
5 | #ifndef __LINUX_FILE_H | |
6 | #define __LINUX_FILE_H | |
7 | ||
8 | #include <asm/atomic.h> | |
9 | #include <linux/posix_types.h> | |
10 | #include <linux/compiler.h> | |
11 | #include <linux/spinlock.h> | |
ab2af1f5 | 12 | #include <linux/rcupdate.h> |
0c9e63fd | 13 | #include <linux/types.h> |
1da177e4 LT |
14 | |
15 | /* | |
16 | * The default fd array needs to be at least BITS_PER_LONG, | |
17 | * as this is the granularity returned by copy_fdset(). | |
18 | */ | |
19 | #define NR_OPEN_DEFAULT BITS_PER_LONG | |
20 | ||
0c9e63fd ED |
21 | /* |
22 | * The embedded_fd_set is a small fd_set, | |
23 | * suitable for most tasks (which open <= BITS_PER_LONG files) | |
24 | */ | |
25 | struct embedded_fd_set { | |
26 | unsigned long fds_bits[1]; | |
27 | }; | |
28 | ||
29 | /* | |
30 | * More than this number of fds: we use a separately allocated fd_set | |
31 | */ | |
32 | #define EMBEDDED_FD_SET_SIZE (BITS_PER_BYTE * sizeof(struct embedded_fd_set)) | |
33 | ||
badf1662 DS |
34 | struct fdtable { |
35 | unsigned int max_fds; | |
36 | int max_fdset; | |
badf1662 DS |
37 | struct file ** fd; /* current fd array */ |
38 | fd_set *close_on_exec; | |
39 | fd_set *open_fds; | |
ab2af1f5 DS |
40 | struct rcu_head rcu; |
41 | struct files_struct *free_files; | |
42 | struct fdtable *next; | |
badf1662 DS |
43 | }; |
44 | ||
1da177e4 LT |
45 | /* |
46 | * Open file table structure | |
47 | */ | |
48 | struct files_struct { | |
0c9e63fd ED |
49 | /* |
50 | * read mostly part | |
51 | */ | |
95e861db | 52 | atomic_t count; |
ab2af1f5 | 53 | struct fdtable *fdt; |
badf1662 | 54 | struct fdtable fdtab; |
0c9e63fd ED |
55 | /* |
56 | * written part on a separate cache line in SMP | |
57 | */ | |
58 | spinlock_t file_lock ____cacheline_aligned_in_smp; | |
59 | int next_fd; | |
60 | struct embedded_fd_set close_on_exec_init; | |
61 | struct embedded_fd_set open_fds_init; | |
95e861db | 62 | struct file * fd_array[NR_OPEN_DEFAULT]; |
1da177e4 LT |
63 | }; |
64 | ||
ab2af1f5 | 65 | #define files_fdtable(files) (rcu_dereference((files)->fdt)) |
badf1662 | 66 | |
1da177e4 LT |
67 | extern void FASTCALL(__fput(struct file *)); |
68 | extern void FASTCALL(fput(struct file *)); | |
69 | ||
70 | static inline void fput_light(struct file *file, int fput_needed) | |
71 | { | |
72 | if (unlikely(fput_needed)) | |
73 | fput(file); | |
74 | } | |
75 | ||
76 | extern struct file * FASTCALL(fget(unsigned int fd)); | |
77 | extern struct file * FASTCALL(fget_light(unsigned int fd, int *fput_needed)); | |
78 | extern void FASTCALL(set_close_on_exec(unsigned int fd, int flag)); | |
79 | extern void put_filp(struct file *); | |
80 | extern int get_unused_fd(void); | |
81 | extern void FASTCALL(put_unused_fd(unsigned int fd)); | |
2109a2d1 | 82 | struct kmem_cache; |
1da177e4 LT |
83 | |
84 | extern struct file ** alloc_fd_array(int); | |
85 | extern void free_fd_array(struct file **, int); | |
86 | ||
87 | extern fd_set *alloc_fdset(int); | |
88 | extern void free_fdset(fd_set *, int); | |
89 | ||
90 | extern int expand_files(struct files_struct *, int nr); | |
ab2af1f5 DS |
91 | extern void free_fdtable(struct fdtable *fdt); |
92 | extern void __init files_defer_init(void); | |
1da177e4 LT |
93 | |
94 | static inline struct file * fcheck_files(struct files_struct *files, unsigned int fd) | |
95 | { | |
96 | struct file * file = NULL; | |
badf1662 | 97 | struct fdtable *fdt = files_fdtable(files); |
1da177e4 | 98 | |
badf1662 | 99 | if (fd < fdt->max_fds) |
ab2af1f5 | 100 | file = rcu_dereference(fdt->fd[fd]); |
1da177e4 LT |
101 | return file; |
102 | } | |
103 | ||
104 | /* | |
105 | * Check whether the specified fd has an open file. | |
106 | */ | |
107 | #define fcheck(fd) fcheck_files(current->files, fd) | |
108 | ||
109 | extern void FASTCALL(fd_install(unsigned int fd, struct file * file)); | |
110 | ||
111 | struct task_struct; | |
112 | ||
113 | struct files_struct *get_files_struct(struct task_struct *); | |
114 | void FASTCALL(put_files_struct(struct files_struct *fs)); | |
115 | ||
116 | #endif /* __LINUX_FILE_H */ |