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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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>
Dipankar Sarmaab2af1f2005-09-09 13:04:13 -070012#include <linux/rcupdate.h>
Eric Dumazet0c9e63f2006-03-23 03:00:12 -080013#include <linux/types.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070014
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
Eric Dumazet0c9e63f2006-03-23 03:00:12 -080021/*
22 * The embedded_fd_set is a small fd_set,
23 * suitable for most tasks (which open <= BITS_PER_LONG files)
24 */
25struct embedded_fd_set {
26 unsigned long fds_bits[1];
27};
28
Dipankar Sarmabadf1662005-09-09 13:04:10 -070029struct fdtable {
30 unsigned int max_fds;
Dipankar Sarmabadf1662005-09-09 13:04:10 -070031 struct file ** fd; /* current fd array */
32 fd_set *close_on_exec;
33 fd_set *open_fds;
Dipankar Sarmaab2af1f2005-09-09 13:04:13 -070034 struct rcu_head rcu;
Dipankar Sarmaab2af1f2005-09-09 13:04:13 -070035 struct fdtable *next;
Dipankar Sarmabadf1662005-09-09 13:04:10 -070036};
37
Linus Torvalds1da177e2005-04-16 15:20:36 -070038/*
39 * Open file table structure
40 */
41struct files_struct {
Eric Dumazet0c9e63f2006-03-23 03:00:12 -080042 /*
43 * read mostly part
44 */
Eric Dumazet95e861d2005-11-13 16:06:24 -080045 atomic_t count;
Dipankar Sarmaab2af1f2005-09-09 13:04:13 -070046 struct fdtable *fdt;
Dipankar Sarmabadf1662005-09-09 13:04:10 -070047 struct fdtable fdtab;
Eric Dumazet0c9e63f2006-03-23 03:00:12 -080048 /*
49 * written part on a separate cache line in SMP
50 */
51 spinlock_t file_lock ____cacheline_aligned_in_smp;
52 int next_fd;
53 struct embedded_fd_set close_on_exec_init;
54 struct embedded_fd_set open_fds_init;
Eric Dumazet95e861d2005-11-13 16:06:24 -080055 struct file * fd_array[NR_OPEN_DEFAULT];
Linus Torvalds1da177e2005-04-16 15:20:36 -070056};
57
Dipankar Sarmaab2af1f2005-09-09 13:04:13 -070058#define files_fdtable(files) (rcu_dereference((files)->fdt))
Dipankar Sarmabadf1662005-09-09 13:04:10 -070059
Christoph Lameter8b7d91e2006-12-06 20:32:52 -080060extern struct kmem_cache *filp_cachep;
61
Linus Torvalds1da177e2005-04-16 15:20:36 -070062extern void FASTCALL(__fput(struct file *));
63extern void FASTCALL(fput(struct file *));
64
65static inline void fput_light(struct file *file, int fput_needed)
66{
67 if (unlikely(fput_needed))
68 fput(file);
69}
70
71extern struct file * FASTCALL(fget(unsigned int fd));
72extern struct file * FASTCALL(fget_light(unsigned int fd, int *fput_needed));
73extern void FASTCALL(set_close_on_exec(unsigned int fd, int flag));
74extern void put_filp(struct file *);
75extern int get_unused_fd(void);
Ulrich Drepper4a195422007-07-15 23:40:34 -070076extern int get_unused_fd_flags(int flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -070077extern void FASTCALL(put_unused_fd(unsigned int fd));
Pekka J Enberg2109a2d2005-11-07 00:58:01 -080078struct kmem_cache;
Linus Torvalds1da177e2005-04-16 15:20:36 -070079
Linus Torvalds1da177e2005-04-16 15:20:36 -070080extern int expand_files(struct files_struct *, int nr);
Vadim Lobanov4fd45812006-12-10 02:21:17 -080081extern void free_fdtable_rcu(struct rcu_head *rcu);
Dipankar Sarmaab2af1f2005-09-09 13:04:13 -070082extern void __init files_defer_init(void);
Linus Torvalds1da177e2005-04-16 15:20:36 -070083
Vadim Lobanov01b2d932006-12-22 01:10:43 -080084static inline void free_fdtable(struct fdtable *fdt)
85{
86 call_rcu(&fdt->rcu, free_fdtable_rcu);
87}
88
Linus Torvalds1da177e2005-04-16 15:20:36 -070089static inline struct file * fcheck_files(struct files_struct *files, unsigned int fd)
90{
91 struct file * file = NULL;
Dipankar Sarmabadf1662005-09-09 13:04:10 -070092 struct fdtable *fdt = files_fdtable(files);
Linus Torvalds1da177e2005-04-16 15:20:36 -070093
Dipankar Sarmabadf1662005-09-09 13:04:10 -070094 if (fd < fdt->max_fds)
Dipankar Sarmaab2af1f2005-09-09 13:04:13 -070095 file = rcu_dereference(fdt->fd[fd]);
Linus Torvalds1da177e2005-04-16 15:20:36 -070096 return file;
97}
98
99/*
100 * Check whether the specified fd has an open file.
101 */
102#define fcheck(fd) fcheck_files(current->files, fd)
103
104extern void FASTCALL(fd_install(unsigned int fd, struct file * file));
105
106struct task_struct;
107
108struct files_struct *get_files_struct(struct task_struct *);
109void FASTCALL(put_files_struct(struct files_struct *fs));
Kirill Korotaev3b9b8ab2006-09-29 02:00:05 -0700110void reset_files_struct(struct task_struct *, struct files_struct *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700111
Christoph Lameter5d6538f2006-12-06 20:32:50 -0800112extern struct kmem_cache *files_cachep;
113
Linus Torvalds1da177e2005-04-16 15:20:36 -0700114#endif /* __LINUX_FILE_H */