original development tree for Linux kernel GTP module; now long in mainline.
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/*
* 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];
};
struct fdtable {
unsigned int max_fds;
struct file ** fd; /* current fd array */
fd_set *close_on_exec;
fd_set *open_fds;
struct rcu_head rcu;
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 struct kmem_cache *filp_cachep;
extern void __fput(struct file *);
extern void fput(struct file *);
extern void drop_file_write_access(struct file *file);
struct file_operations;
struct vfsmount;
struct dentry;
extern int init_file(struct file *, struct vfsmount *mnt,
struct dentry *dentry, mode_t mode,
const struct file_operations *fop);
extern struct file *alloc_file(struct vfsmount *, struct dentry *dentry,
mode_t mode, const struct file_operations *fop);
static inline void fput_light(struct file *file, int fput_needed)
{
if (unlikely(fput_needed))
fput(file);
}
extern struct file *fget(unsigned int fd);
extern struct file *fget_light(unsigned int fd, int *fput_needed);
extern void set_close_on_exec(unsigned int fd, int flag);
extern void put_filp(struct file *);
extern int get_unused_fd(void);
extern int get_unused_fd_flags(int flags);
extern void put_unused_fd(unsigned int fd);
struct kmem_cache;
extern int expand_files(struct files_struct *, int nr);
extern void free_fdtable_rcu(struct rcu_head *rcu);
extern void __init files_defer_init(void);
static inline void free_fdtable(struct fdtable *fdt)
{
call_rcu(&fdt->rcu, free_fdtable_rcu);
}
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 fd_install(unsigned int fd, struct file *file);
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 **);
extern struct kmem_cache *files_cachep;
#endif /* __LINUX_FILE_H */