/* * 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 *); 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 task_struct *, struct files_struct *); extern struct kmem_cache *files_cachep; #endif /* __LINUX_FILE_H */