Commit de12c339 authored by Al Viro's avatar Al Viro
Browse files

add struct fd constructors, get rid of __to_fd() 



	Make __fdget() et.al. return struct fd directly.
New helpers: BORROWED_FD(file) and CLONED_FD(file), for
borrowed and cloned file references resp.

	NOTE: this might need tuning; in particular, inline on
__fget_light() is there to keep the code generation same as
before - we probably want to keep it inlined in fdget() et.al.
(especially so in fdget_pos()), but that needs profiling.

Reviewed-by: default avatarChristian Brauner <brauner@kernel.org>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 88a2f646

fs/file.c

+13 −13
Original line number Diff line number Diff line
@@ -1128,7 +1128,7 @@ EXPORT_SYMBOL(task_lookup_next_fdget_rcu); 
 * The fput_needed flag returned by fget_light should be passed to the

 * corresponding fput_light.

 */

static unsigned long __fget_light(unsigned int fd, fmode_t mask)

static inline struct fd __fget_light(unsigned int fd, fmode_t mask)

{

	struct files_struct *files = current->files;

	struct file *file;
@@ -1145,22 +1145,22 @@ static unsigned long __fget_light(unsigned int fd, fmode_t mask) 
	if (likely(atomic_read_acquire(&files->count) == 1)) {

		file = files_lookup_fd_raw(files, fd);

		if (!file || unlikely(file->f_mode & mask))

			return 0;

		return (unsigned long)file;

			return EMPTY_FD;

		return BORROWED_FD(file);

	} else {

		file = __fget_files(files, fd, mask);

		if (!file)

			return 0;

		return FDPUT_FPUT | (unsigned long)file;

			return EMPTY_FD;

		return CLONED_FD(file);

	}

}

unsigned long __fdget(unsigned int fd)

struct fd fdget(unsigned int fd)

{

	return __fget_light(fd, FMODE_PATH);

}

EXPORT_SYMBOL(__fdget);

EXPORT_SYMBOL(fdget);



unsigned long __fdget_raw(unsigned int fd)

struct fd fdget_raw(unsigned int fd)

{

	return __fget_light(fd, 0);

}
@@ -1181,16 +1181,16 @@ static inline bool file_needs_f_pos_lock(struct file *file) 
		(file_count(file) > 1 || file->f_op->iterate_shared);

}



unsigned long __fdget_pos(unsigned int fd)

struct fd fdget_pos(unsigned int fd)

{

	unsigned long v = __fdget(fd);

	struct file *file = (struct file *)(v & ~3);

	struct fd f = fdget(fd);

	struct file *file = fd_file(f);



	if (file && file_needs_f_pos_lock(file)) {

		v |= FDPUT_POS_UNLOCK;

		f.word |= FDPUT_POS_UNLOCK;

		mutex_lock(&file->f_pos_lock);

	}

	return v;

	return f;

}



void __f_unlock_pos(struct file *f)

include/linux/file.h

+11 −22
Original line number Diff line number Diff line
@@ -53,6 +53,14 @@ static inline bool fd_empty(struct fd f) 
}



#define EMPTY_FD (struct fd){0}

static inline struct fd BORROWED_FD(struct file *f)

{

	return (struct fd){(unsigned long)f};

}

static inline struct fd CLONED_FD(struct file *f)

{

	return (struct fd){(unsigned long)f | FDPUT_FPUT};

}



static inline void fdput(struct fd fd)

{
@@ -63,30 +71,11 @@ static inline void fdput(struct fd fd) 
extern struct file *fget(unsigned int fd);

extern struct file *fget_raw(unsigned int fd);

extern struct file *fget_task(struct task_struct *task, unsigned int fd);

extern unsigned long __fdget(unsigned int fd);

extern unsigned long __fdget_raw(unsigned int fd);

extern unsigned long __fdget_pos(unsigned int fd);

extern void __f_unlock_pos(struct file *);



static inline struct fd __to_fd(unsigned long v)

{

	return (struct fd){v};

}



static inline struct fd fdget(unsigned int fd)

{

	return __to_fd(__fdget(fd));

}



static inline struct fd fdget_raw(unsigned int fd)

{

	return __to_fd(__fdget_raw(fd));

}



static inline struct fd fdget_pos(int fd)

{

	return __to_fd(__fdget_pos(fd));

}

struct fd fdget(unsigned int fd);

struct fd fdget_raw(unsigned int fd);

struct fd fdget_pos(unsigned int fd);



static inline void fdput_pos(struct fd f)

{