#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,
*/
#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;
- int next_fd;
struct file ** fd; /* current fd array */
fd_set *close_on_exec;
fd_set *open_fds;
* Open file table structure
*/
struct files_struct {
- atomic_t count;
- spinlock_t file_lock; /* Protects all the below members. Nests inside tsk->alloc_lock */
+ /*
+ * read mostly part
+ */
+ atomic_t count;
struct fdtable *fdt;
struct fdtable fdtab;
- fd_set close_on_exec_init;
- fd_set open_fds_init;
- struct file * fd_array[NR_OPEN_DEFAULT];
+ /*
+ * 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 int get_unused_fd(void);
extern void FASTCALL(put_unused_fd(unsigned int fd));
struct kmem_cache;
-extern void filp_ctor(void * objp, struct kmem_cache *cachep, unsigned long cflags);
-extern void filp_dtor(void * objp, struct kmem_cache *cachep, unsigned long dflags);
extern struct file ** alloc_fd_array(int);
extern void free_fd_array(struct file **, int);
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 *);
#endif /* __LINUX_FILE_H */