/* * 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> /* * 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;	int max_fdset;	int next_fd;	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 {        atomic_t count;        spinlock_t file_lock;     /* Protects all the below members.  Nests inside tsk->alloc_lock */	struct fdtable *fdt;	struct fdtable fdtab;        fd_set close_on_exec_init;        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_s;extern void filp_ctor(void * objp, struct kmem_cache_s *cachep, unsigned long cflags);extern void filp_dtor(void * objp, struct kmem_cache_s *cachep, unsigned long dflags); 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 */