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>
16 #include <linux/atomic.h>
19 * The default fd array needs to be at least BITS_PER_LONG,
20 * as this is the granularity returned by copy_fdset().
22 #define NR_OPEN_DEFAULT BITS_PER_LONG
25 * The embedded_fd_set is a small fd_set,
26 * suitable for most tasks (which open <= BITS_PER_LONG files)
28 struct embedded_fd_set {
29 unsigned long fds_bits[1];
34 struct file __rcu **fd; /* current fd array */
35 fd_set *close_on_exec;
41 static inline void __set_close_on_exec(int fd, struct fdtable *fdt)
43 FD_SET(fd, fdt->close_on_exec);
46 static inline void __clear_close_on_exec(int fd, struct fdtable *fdt)
48 FD_CLR(fd, fdt->close_on_exec);
51 static inline bool close_on_exec(int fd, const struct fdtable *fdt)
53 return FD_ISSET(fd, fdt->close_on_exec);
56 static inline void __set_open_fd(int fd, struct fdtable *fdt)
58 FD_SET(fd, fdt->open_fds);
61 static inline void __clear_open_fd(int fd, struct fdtable *fdt)
63 FD_CLR(fd, fdt->open_fds);
66 static inline bool fd_is_open(int fd, const struct fdtable *fdt)
68 return FD_ISSET(fd, fdt->open_fds);
72 * Open file table structure
79 struct fdtable __rcu *fdt;
82 * written part on a separate cache line in SMP
84 spinlock_t file_lock ____cacheline_aligned_in_smp;
86 struct embedded_fd_set close_on_exec_init;
87 struct embedded_fd_set open_fds_init;
88 struct file __rcu * fd_array[NR_OPEN_DEFAULT];
91 #define rcu_dereference_check_fdtable(files, fdtfd) \
92 (rcu_dereference_check((fdtfd), \
93 lockdep_is_held(&(files)->file_lock) || \
94 atomic_read(&(files)->count) == 1 || \
95 rcu_my_thread_group_empty()))
97 #define files_fdtable(files) \
98 (rcu_dereference_check_fdtable((files), (files)->fdt))
100 struct file_operations;
104 extern int expand_files(struct files_struct *, int nr);
105 extern void free_fdtable_rcu(struct rcu_head *rcu);
106 extern void __init files_defer_init(void);
108 static inline void free_fdtable(struct fdtable *fdt)
110 call_rcu(&fdt->rcu, free_fdtable_rcu);
113 static inline struct file * fcheck_files(struct files_struct *files, unsigned int fd)
115 struct file * file = NULL;
116 struct fdtable *fdt = files_fdtable(files);
118 if (fd < fdt->max_fds)
119 file = rcu_dereference_check_fdtable(files, fdt->fd[fd]);
124 * Check whether the specified fd has an open file.
126 #define fcheck(fd) fcheck_files(current->files, fd)
130 struct files_struct *get_files_struct(struct task_struct *);
131 void put_files_struct(struct files_struct *fs);
132 void reset_files_struct(struct files_struct *);
133 int unshare_files(struct files_struct **);
134 struct files_struct *dup_fd(struct files_struct *, int *);
136 extern struct kmem_cache *files_cachep;
138 #endif /* __LINUX_FDTABLE_H */