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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 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 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 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));
- void reset_files_struct(struct task_struct *, struct files_struct *);
- extern struct kmem_cache *files_cachep;
- #endif /* __LINUX_FILE_H */
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