[linux-2.6-block.git] / include / linux / fdtable.h

/*
 * descriptor table internals; you almost certainly want file.h instead.
 */

#ifndef __LINUX_FDTABLE_H
#define __LINUX_FDTABLE_H

#include <linux/posix_types.h>
#include <linux/compiler.h>
#include <linux/spinlock.h>
#include <linux/rcupdate.h>
#include <linux/types.h>
#include <linux/init.h>
#include <linux/fs.h>

#include <linux/atomic.h>

/*
 * The default fd array needs to be at least BITS_PER_LONG,
 * as this is the granularity returned by copy_fdset().
 */
#define NR_OPEN_DEFAULT BITS_PER_LONG

struct fdtable {
	unsigned int max_fds;
	struct file __rcu **fd;      /* current fd array */
	unsigned long *close_on_exec;
	unsigned long *open_fds;
	struct rcu_head rcu;
};

static inline bool close_on_exec(int fd, const struct fdtable *fdt)
{
	return test_bit(fd, fdt->close_on_exec);
}

static inline bool fd_is_open(int fd, const struct fdtable *fdt)
{
	return test_bit(fd, fdt->open_fds);
}

/*
 * Open file table structure
 */
struct files_struct {
  /*
   * read mostly part
   */
	atomic_t count;
	bool resize_in_progress;
	wait_queue_head_t resize_wait;

	struct fdtable __rcu *fdt;
	struct fdtable fdtab;
  /*
   * written part on a separate cache line in SMP
   */
	spinlock_t file_lock ____cacheline_aligned_in_smp;
	int next_fd;
	unsigned long close_on_exec_init[1];
	unsigned long open_fds_init[1];
	struct file __rcu * fd_array[NR_OPEN_DEFAULT];
};

struct file_operations;
struct vfsmount;
struct dentry;

#define rcu_dereference_check_fdtable(files, fdtfd) \
	rcu_dereference_check((fdtfd), lockdep_is_held(&(files)->file_lock))

#define files_fdtable(files) \
	rcu_dereference_check_fdtable((files), (files)->fdt)

/*
 * The caller must ensure that fd table isn't shared or hold rcu or file lock
 */
static inline struct file *__fcheck_files(struct files_struct *files, unsigned int fd)
{
	struct fdtable *fdt = rcu_dereference_raw(files->fdt);

	if (fd < fdt->max_fds)
		return rcu_dereference_raw(fdt->fd[fd]);
	return NULL;
}

static inline struct file *fcheck_files(struct files_struct *files, unsigned int fd)
{
	RCU_LOCKDEP_WARN(!rcu_read_lock_held() &&
			   !lockdep_is_held(&files->file_lock),
			   "suspicious rcu_dereference_check() usage");
	return __fcheck_files(files, fd);
}

/*
 * Check whether the specified fd has an open file.
 */
#define fcheck(fd)	fcheck_files(current->files, fd)

struct task_struct;

struct files_struct *get_files_struct(struct task_struct *);
void put_files_struct(struct files_struct *fs);
void reset_files_struct(struct files_struct *);
int unshare_files(struct files_struct **);
struct files_struct *dup_fd(struct files_struct *, int *);
void do_close_on_exec(struct files_struct *);
int iterate_fd(struct files_struct *, unsigned,
		int (*)(const void *, struct file *, unsigned),
		const void *);

extern int __alloc_fd(struct files_struct *files,
		      unsigned start, unsigned end, unsigned flags);
extern void __fd_install(struct files_struct *files,
		      unsigned int fd, struct file *file);
extern int __close_fd(struct files_struct *files,
		      unsigned int fd);

extern struct kmem_cache *files_cachep;

#endif /* __LINUX_FDTABLE_H */
Commit	Line	Data
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	15
60063497	16	#include <linux/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
9f3acc31 AV	24	struct fdtable {
9f3acc31 AV	25	unsigned int max_fds;
4d2deb40	26	struct file __rcu *fd; / current fd array */
1fd36adc DH	27	unsigned long *close_on_exec;
1fd36adc DH	28	unsigned long *open_fds;
9f3acc31	29	struct rcu_head rcu;
9f3acc31 AV	30	};
9f3acc31 AV	31
1dce27c5 DH	32	static inline bool close_on_exec(int fd, const struct fdtable *fdt)
1dce27c5 DH	33	{
1fd36adc	34	return test_bit(fd, fdt->close_on_exec);
1dce27c5 DH	35	}
1dce27c5 DH	36
1dce27c5 DH	37	static inline bool fd_is_open(int fd, const struct fdtable *fdt)
1dce27c5 DH	38	{
1fd36adc	39	return test_bit(fd, fdt->open_fds);
1dce27c5 DH	40	}
1dce27c5 DH	41
9f3acc31 AV	42	/*
	43	* Open file table structure
	44	*/
	45	struct files_struct {
	46	/*
	47	* read mostly part
	48	*/
	49	atomic_t count;
8a81252b ED	50	bool resize_in_progress;
	51	wait_queue_head_t resize_wait;
	52
4d2deb40	53	struct fdtable __rcu *fdt;
9f3acc31 AV	54	struct fdtable fdtab;
	55	/*
	56	* written part on a separate cache line in SMP
	57	*/
	58	spinlock_t file_lock ____cacheline_aligned_in_smp;
	59	int next_fd;
1fd36adc DH	60	unsigned long close_on_exec_init[1];
1fd36adc DH	61	unsigned long open_fds_init[1];
4d2deb40	62	struct file __rcu * fd_array[NR_OPEN_DEFAULT];
9f3acc31 AV	63	};
9f3acc31 AV	64
9f3acc31 AV	65	struct file_operations;
	66	struct vfsmount;
	67	struct dentry;
	68
a8d4b834 ON	69	#define rcu_dereference_check_fdtable(files, fdtfd) \
	70	rcu_dereference_check((fdtfd), lockdep_is_held(&(files)->file_lock))
	71
	72	#define files_fdtable(files) \
	73	rcu_dereference_check_fdtable((files), (files)->fdt)
	74
	75	/*
	76	* The caller must ensure that fd table isn't shared or hold rcu or file lock
	77	*/
	78	static inline struct file __fcheck_files(struct files_struct files, unsigned int fd)
9f3acc31	79	{
a8d4b834	80	struct fdtable *fdt = rcu_dereference_raw(files->fdt);
9f3acc31 AV	81
9f3acc31 AV	82	if (fd < fdt->max_fds)
a8d4b834 ON	83	return rcu_dereference_raw(fdt->fd[fd]);
	84	return NULL;
	85	}
	86
	87	static inline struct file fcheck_files(struct files_struct files, unsigned int fd)
	88	{
f78f5b90 PM	89	RCU_LOCKDEP_WARN(!rcu_read_lock_held() &&
f78f5b90 PM	90	!lockdep_is_held(&files->file_lock),
a8d4b834 ON	91	"suspicious rcu_dereference_check() usage");
a8d4b834 ON	92	return __fcheck_files(files, fd);
9f3acc31 AV	93	}
	94
	95	/*
	96	* Check whether the specified fd has an open file.
	97	*/
	98	#define fcheck(fd) fcheck_files(current->files, fd)
	99
	100	struct task_struct;
	101
	102	struct files_struct get_files_struct(struct task_struct );
	103	void put_files_struct(struct files_struct *fs);
	104	void reset_files_struct(struct files_struct *);
	105	int unshare_files(struct files_struct **);
02afc626	106	struct files_struct dup_fd(struct files_struct , int *);
6a6d27de	107	void do_close_on_exec(struct files_struct *);
c3c073f8 AV	108	int iterate_fd(struct files_struct *, unsigned,
	109	int ()(const void , struct file *, unsigned),
	110	const void *);
9f3acc31	111
dcfadfa4 AV	112	extern int __alloc_fd(struct files_struct *files,
dcfadfa4 AV	113	unsigned start, unsigned end, unsigned flags);
f869e8a7 AV	114	extern void __fd_install(struct files_struct *files,
f869e8a7 AV	115	unsigned int fd, struct file *file);
483ce1d4 AV	116	extern int __close_fd(struct files_struct *files,
483ce1d4 AV	117	unsigned int fd);
dcfadfa4	118
9f3acc31 AV	119	extern struct kmem_cache *files_cachep;
	120
	121	#endif /* __LINUX_FDTABLE_H */