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 | 13 | #include <linux/init.h> |
2c666df8 | 14 | #include <linux/fs.h> |
21e54459 IM |
15 | |
16 | #include <asm/atomic.h> | |
9f3acc31 AV |
17 | |
18 | /* | |
19 | * The default fd array needs to be at least BITS_PER_LONG, | |
20 | * as this is the granularity returned by copy_fdset(). | |
21 | */ | |
22 | #define NR_OPEN_DEFAULT BITS_PER_LONG | |
23 | ||
24 | /* | |
25 | * The embedded_fd_set is a small fd_set, | |
26 | * suitable for most tasks (which open <= BITS_PER_LONG files) | |
27 | */ | |
28 | struct embedded_fd_set { | |
29 | unsigned long fds_bits[1]; | |
30 | }; | |
31 | ||
32 | struct fdtable { | |
33 | unsigned int max_fds; | |
4d2deb40 | 34 | struct file __rcu **fd; /* current fd array */ |
9f3acc31 AV |
35 | fd_set *close_on_exec; |
36 | fd_set *open_fds; | |
37 | struct rcu_head rcu; | |
38 | struct fdtable *next; | |
39 | }; | |
40 | ||
41 | /* | |
42 | * Open file table structure | |
43 | */ | |
44 | struct files_struct { | |
45 | /* | |
46 | * read mostly part | |
47 | */ | |
48 | atomic_t count; | |
4d2deb40 | 49 | struct fdtable __rcu *fdt; |
9f3acc31 AV |
50 | struct fdtable fdtab; |
51 | /* | |
52 | * written part on a separate cache line in SMP | |
53 | */ | |
54 | spinlock_t file_lock ____cacheline_aligned_in_smp; | |
55 | int next_fd; | |
56 | struct embedded_fd_set close_on_exec_init; | |
57 | struct embedded_fd_set open_fds_init; | |
4d2deb40 | 58 | struct file __rcu * fd_array[NR_OPEN_DEFAULT]; |
9f3acc31 AV |
59 | }; |
60 | ||
af61b96b PM |
61 | #define rcu_dereference_check_fdtable(files, fdtfd) \ |
62 | (rcu_dereference_check((fdtfd), \ | |
7dc52157 PM |
63 | rcu_read_lock_held() || \ |
64 | lockdep_is_held(&(files)->file_lock) || \ | |
844b9a87 PM |
65 | atomic_read(&(files)->count) == 1 || \ |
66 | rcu_my_thread_group_empty())) | |
af61b96b PM |
67 | |
68 | #define files_fdtable(files) \ | |
69 | (rcu_dereference_check_fdtable((files), (files)->fdt)) | |
9f3acc31 | 70 | |
9f3acc31 AV |
71 | struct file_operations; |
72 | struct vfsmount; | |
73 | struct dentry; | |
74 | ||
75 | extern int expand_files(struct files_struct *, int nr); | |
76 | extern void free_fdtable_rcu(struct rcu_head *rcu); | |
77 | extern void __init files_defer_init(void); | |
78 | ||
79 | static inline void free_fdtable(struct fdtable *fdt) | |
80 | { | |
81 | call_rcu(&fdt->rcu, free_fdtable_rcu); | |
82 | } | |
83 | ||
84 | static inline struct file * fcheck_files(struct files_struct *files, unsigned int fd) | |
85 | { | |
86 | struct file * file = NULL; | |
87 | struct fdtable *fdt = files_fdtable(files); | |
88 | ||
89 | if (fd < fdt->max_fds) | |
af61b96b | 90 | file = rcu_dereference_check_fdtable(files, fdt->fd[fd]); |
9f3acc31 AV |
91 | return file; |
92 | } | |
93 | ||
94 | /* | |
95 | * Check whether the specified fd has an open file. | |
96 | */ | |
97 | #define fcheck(fd) fcheck_files(current->files, fd) | |
98 | ||
99 | struct task_struct; | |
100 | ||
101 | struct files_struct *get_files_struct(struct task_struct *); | |
102 | void put_files_struct(struct files_struct *fs); | |
103 | void reset_files_struct(struct files_struct *); | |
104 | int unshare_files(struct files_struct **); | |
02afc626 | 105 | struct files_struct *dup_fd(struct files_struct *, int *); |
9f3acc31 AV |
106 | |
107 | extern struct kmem_cache *files_cachep; | |
108 | ||
109 | #endif /* __LINUX_FDTABLE_H */ |