2 * descriptor table internals; you almost certainly want file.h instead.
5 #ifndef __LINUX_FDTABLE_H
6 #define __LINUX_FDTABLE_H
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>
13 #include <linux/init.h>
15 #include <asm/atomic.h>
18 * The default fd array needs to be at least BITS_PER_LONG,
19 * as this is the granularity returned by copy_fdset().
21 #define NR_OPEN_DEFAULT BITS_PER_LONG
24 * The embedded_fd_set is a small fd_set,
25 * suitable for most tasks (which open <= BITS_PER_LONG files)
27 struct embedded_fd_set {
28 unsigned long fds_bits[1];
33 struct file ** fd; /* current fd array */
34 fd_set *close_on_exec;
41 * Open file table structure
51 * written part on a separate cache line in SMP
53 spinlock_t file_lock ____cacheline_aligned_in_smp;
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];
60 #define files_fdtable(files) \
61 (rcu_dereference_check((files)->fdt, \
62 rcu_read_lock_held() || \
63 lockdep_is_held(&(files)->file_lock) || \
64 atomic_read(&files->count) == 1))
66 struct file_operations;
70 extern int expand_files(struct files_struct *, int nr);
71 extern void free_fdtable_rcu(struct rcu_head *rcu);
72 extern void __init files_defer_init(void);
74 static inline void free_fdtable(struct fdtable *fdt)
76 call_rcu(&fdt->rcu, free_fdtable_rcu);
79 static inline struct file * fcheck_files(struct files_struct *files, unsigned int fd)
81 struct file * file = NULL;
82 struct fdtable *fdt = files_fdtable(files);
84 if (fd < fdt->max_fds)
85 file = rcu_dereference_check(fdt->fd[fd], rcu_read_lock_held() || lockdep_is_held(&files->file_lock) || atomic_read(&files->count) == 1);
90 * Check whether the specified fd has an open file.
92 #define fcheck(fd) fcheck_files(current->files, fd)
96 struct files_struct *get_files_struct(struct task_struct *);
97 void put_files_struct(struct files_struct *fs);
98 void reset_files_struct(struct files_struct *);
99 int unshare_files(struct files_struct **);
100 struct files_struct *dup_fd(struct files_struct *, int *);
102 extern struct kmem_cache *files_cachep;
104 #endif /* __LINUX_FDTABLE_H */