Commit | Line | Data |
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9f3acc31 AV |
1 | /* |
2 | * descriptor table internals; you almost certainly want file.h instead. | |
3 | */ | |
4 | ||
5 | #ifndef __LINUX_FDTABLE_H | |
6 | #define __LINUX_FDTABLE_H | |
7 | ||
9f3acc31 AV |
8 | #include <linux/posix_types.h> |
9 | #include <linux/compiler.h> | |
10 | #include <linux/spinlock.h> | |
11 | #include <linux/rcupdate.h> | |
12 | #include <linux/types.h> | |
21e54459 IM |
13 | #include <linux/init.h> |
14 | ||
15 | #include <asm/atomic.h> | |
9f3acc31 AV |
16 | |
17 | /* | |
18 | * The default fd array needs to be at least BITS_PER_LONG, | |
19 | * as this is the granularity returned by copy_fdset(). | |
20 | */ | |
21 | #define NR_OPEN_DEFAULT BITS_PER_LONG | |
22 | ||
23 | /* | |
24 | * The embedded_fd_set is a small fd_set, | |
25 | * suitable for most tasks (which open <= BITS_PER_LONG files) | |
26 | */ | |
27 | struct embedded_fd_set { | |
28 | unsigned long fds_bits[1]; | |
29 | }; | |
30 | ||
31 | struct fdtable { | |
32 | unsigned int max_fds; | |
33 | struct file ** fd; /* current fd array */ | |
34 | fd_set *close_on_exec; | |
35 | fd_set *open_fds; | |
36 | struct rcu_head rcu; | |
37 | struct fdtable *next; | |
38 | }; | |
39 | ||
40 | /* | |
41 | * Open file table structure | |
42 | */ | |
43 | struct files_struct { | |
44 | /* | |
45 | * read mostly part | |
46 | */ | |
47 | atomic_t count; | |
48 | struct fdtable *fdt; | |
49 | struct fdtable fdtab; | |
50 | /* | |
51 | * written part on a separate cache line in SMP | |
52 | */ | |
53 | spinlock_t file_lock ____cacheline_aligned_in_smp; | |
54 | int next_fd; | |
55 | struct embedded_fd_set close_on_exec_init; | |
56 | struct embedded_fd_set open_fds_init; | |
57 | struct file * fd_array[NR_OPEN_DEFAULT]; | |
58 | }; | |
59 | ||
af61b96b PM |
60 | #define rcu_dereference_check_fdtable(files, fdtfd) \ |
61 | (rcu_dereference_check((fdtfd), \ | |
7dc52157 PM |
62 | rcu_read_lock_held() || \ |
63 | lockdep_is_held(&(files)->file_lock) || \ | |
af61b96b PM |
64 | atomic_read(&(files)->count) == 1)) |
65 | ||
66 | #define files_fdtable(files) \ | |
67 | (rcu_dereference_check_fdtable((files), (files)->fdt)) | |
9f3acc31 | 68 | |
9f3acc31 AV |
69 | struct file_operations; |
70 | struct vfsmount; | |
71 | struct dentry; | |
72 | ||
73 | extern int expand_files(struct files_struct *, int nr); | |
74 | extern void free_fdtable_rcu(struct rcu_head *rcu); | |
75 | extern void __init files_defer_init(void); | |
76 | ||
77 | static inline void free_fdtable(struct fdtable *fdt) | |
78 | { | |
79 | call_rcu(&fdt->rcu, free_fdtable_rcu); | |
80 | } | |
81 | ||
82 | static inline struct file * fcheck_files(struct files_struct *files, unsigned int fd) | |
83 | { | |
84 | struct file * file = NULL; | |
85 | struct fdtable *fdt = files_fdtable(files); | |
86 | ||
87 | if (fd < fdt->max_fds) | |
af61b96b | 88 | file = rcu_dereference_check_fdtable(files, fdt->fd[fd]); |
9f3acc31 AV |
89 | return file; |
90 | } | |
91 | ||
92 | /* | |
93 | * Check whether the specified fd has an open file. | |
94 | */ | |
95 | #define fcheck(fd) fcheck_files(current->files, fd) | |
96 | ||
97 | struct task_struct; | |
98 | ||
99 | struct files_struct *get_files_struct(struct task_struct *); | |
100 | void put_files_struct(struct files_struct *fs); | |
101 | void reset_files_struct(struct files_struct *); | |
102 | int unshare_files(struct files_struct **); | |
02afc626 | 103 | struct files_struct *dup_fd(struct files_struct *, int *); |
9f3acc31 AV |
104 | |
105 | extern struct kmem_cache *files_cachep; | |
106 | ||
107 | #endif /* __LINUX_FDTABLE_H */ |