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

/*
 * Wrapper functions for accessing the file_struct fd array.
 */

#ifndef __LINUX_FILE_H
#define __LINUX_FILE_H

#include <asm/atomic.h>
#include <linux/posix_types.h>
#include <linux/compiler.h>
#include <linux/spinlock.h>
#include <linux/rcupdate.h>
#include <linux/types.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

/*
 * The embedded_fd_set is a small fd_set,
 * suitable for most tasks (which open <= BITS_PER_LONG files)
 */
struct embedded_fd_set {
	unsigned long fds_bits[1];
};

/*
 * More than this number of fds: we use a separately allocated fd_set
 */
#define EMBEDDED_FD_SET_SIZE (BITS_PER_BYTE * sizeof(struct embedded_fd_set))

struct fdtable {
	unsigned int max_fds;
	int max_fdset;
	struct file ** fd;      /* current fd array */
	fd_set *close_on_exec;
	fd_set *open_fds;
	struct rcu_head rcu;
	struct files_struct *free_files;
	struct fdtable *next;
};

/*
 * Open file table structure
 */
struct files_struct {
  /*
   * read mostly part
   */
	atomic_t count;
	struct fdtable *fdt;
	struct fdtable fdtab;
  /*
   * written part on a separate cache line in SMP
   */
	spinlock_t file_lock ____cacheline_aligned_in_smp;
	int next_fd;
	struct embedded_fd_set close_on_exec_init;
	struct embedded_fd_set open_fds_init;
	struct file * fd_array[NR_OPEN_DEFAULT];
};

#define files_fdtable(files) (rcu_dereference((files)->fdt))

extern void FASTCALL(__fput(struct file *));
extern void FASTCALL(fput(struct file *));

static inline void fput_light(struct file *file, int fput_needed)
{
	if (unlikely(fput_needed))
		fput(file);
}

extern struct file * FASTCALL(fget(unsigned int fd));
extern struct file * FASTCALL(fget_light(unsigned int fd, int *fput_needed));
extern void FASTCALL(set_close_on_exec(unsigned int fd, int flag));
extern void put_filp(struct file *);
extern int get_unused_fd(void);
extern void FASTCALL(put_unused_fd(unsigned int fd));
struct kmem_cache;

extern struct file ** alloc_fd_array(int);
extern void free_fd_array(struct file **, int);

extern fd_set *alloc_fdset(int);
extern void free_fdset(fd_set *, int);

extern int expand_files(struct files_struct *, int nr);
extern void free_fdtable(struct fdtable *fdt);
extern void __init files_defer_init(void);

static inline struct file * fcheck_files(struct files_struct *files, unsigned int fd)
{
	struct file * file = NULL;
	struct fdtable *fdt = files_fdtable(files);

	if (fd < fdt->max_fds)
		file = rcu_dereference(fdt->fd[fd]);
	return file;
}

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

extern void FASTCALL(fd_install(unsigned int fd, struct file * file));

struct task_struct;

struct files_struct *get_files_struct(struct task_struct *);
void FASTCALL(put_files_struct(struct files_struct *fs));

#endif /* __LINUX_FILE_H */
Commit	Line	Data
1da177e4 LT	1	/*
	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>
ab2af1f5	12	#include <linux/rcupdate.h>
0c9e63fd	13	#include <linux/types.h>
1da177e4 LT	14
	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
0c9e63fd ED	21	/*
	22	* The embedded_fd_set is a small fd_set,
	23	* suitable for most tasks (which open <= BITS_PER_LONG files)
	24	*/
	25	struct embedded_fd_set {
	26	unsigned long fds_bits[1];
	27	};
	28
	29	/*
	30	* More than this number of fds: we use a separately allocated fd_set
	31	*/
	32	#define EMBEDDED_FD_SET_SIZE (BITS_PER_BYTE * sizeof(struct embedded_fd_set))
	33
badf1662 DS	34	struct fdtable {
	35	unsigned int max_fds;
	36	int max_fdset;
badf1662 DS	37	struct file ** fd; /* current fd array */
	38	fd_set *close_on_exec;
	39	fd_set *open_fds;
ab2af1f5 DS	40	struct rcu_head rcu;
	41	struct files_struct *free_files;
	42	struct fdtable *next;
badf1662 DS	43	};
badf1662 DS	44
1da177e4 LT	45	/*
	46	* Open file table structure
	47	*/
	48	struct files_struct {
0c9e63fd ED	49	/*
	50	* read mostly part
	51	*/
95e861db	52	atomic_t count;
ab2af1f5	53	struct fdtable *fdt;
badf1662	54	struct fdtable fdtab;
0c9e63fd ED	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;
	60	struct embedded_fd_set close_on_exec_init;
	61	struct embedded_fd_set open_fds_init;
95e861db	62	struct file * fd_array[NR_OPEN_DEFAULT];
1da177e4 LT	63	};
1da177e4 LT	64
ab2af1f5	65	#define files_fdtable(files) (rcu_dereference((files)->fdt))
badf1662	66
1da177e4 LT	67	extern void FASTCALL(__fput(struct file *));
	68	extern void FASTCALL(fput(struct file *));
	69
	70	static inline void fput_light(struct file *file, int fput_needed)
	71	{
	72	if (unlikely(fput_needed))
	73	fput(file);
	74	}
	75
	76	extern struct file * FASTCALL(fget(unsigned int fd));
	77	extern struct file * FASTCALL(fget_light(unsigned int fd, int *fput_needed));
	78	extern void FASTCALL(set_close_on_exec(unsigned int fd, int flag));
	79	extern void put_filp(struct file *);
	80	extern int get_unused_fd(void);
	81	extern void FASTCALL(put_unused_fd(unsigned int fd));
2109a2d1	82	struct kmem_cache;
1da177e4 LT	83
	84	extern struct file ** alloc_fd_array(int);
	85	extern void free_fd_array(struct file **, int);
	86
	87	extern fd_set *alloc_fdset(int);
	88	extern void free_fdset(fd_set *, int);
	89
	90	extern int expand_files(struct files_struct *, int nr);
ab2af1f5 DS	91	extern void free_fdtable(struct fdtable *fdt);
ab2af1f5 DS	92	extern void __init files_defer_init(void);
1da177e4 LT	93
	94	static inline struct file * fcheck_files(struct files_struct *files, unsigned int fd)
	95	{
	96	struct file * file = NULL;
badf1662	97	struct fdtable *fdt = files_fdtable(files);
1da177e4	98
badf1662	99	if (fd < fdt->max_fds)
ab2af1f5	100	file = rcu_dereference(fdt->fd[fd]);
1da177e4 LT	101	return file;
	102	}
	103
	104	/*
	105	* Check whether the specified fd has an open file.
	106	*/
	107	#define fcheck(fd) fcheck_files(current->files, fd)
	108
	109	extern void FASTCALL(fd_install(unsigned int fd, struct file * file));
	110
	111	struct task_struct;
	112
	113	struct files_struct get_files_struct(struct task_struct );
	114	void FASTCALL(put_files_struct(struct files_struct *fs));
	115
	116	#endif /* __LINUX_FILE_H */