Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 0ee8cdfe authored by Al Viro's avatar Al Viro
Browse files

take fget() and friends to fs/file.c 



Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent f869e8a7

fs/file.c

+106 −0
Original line number Diff line number Diff line
@@ -625,3 +625,109 @@ void fd_install(unsigned int fd, struct file *file) 
}



EXPORT_SYMBOL(fd_install);



struct file *fget(unsigned int fd)

{

	struct file *file;

	struct files_struct *files = current->files;



	rcu_read_lock();

	file = fcheck_files(files, fd);

	if (file) {

		/* File object ref couldn't be taken */

		if (file->f_mode & FMODE_PATH ||

		    !atomic_long_inc_not_zero(&file->f_count))

			file = NULL;

	}

	rcu_read_unlock();



	return file;

}



EXPORT_SYMBOL(fget);



struct file *fget_raw(unsigned int fd)

{

	struct file *file;

	struct files_struct *files = current->files;



	rcu_read_lock();

	file = fcheck_files(files, fd);

	if (file) {

		/* File object ref couldn't be taken */

		if (!atomic_long_inc_not_zero(&file->f_count))

			file = NULL;

	}

	rcu_read_unlock();



	return file;

}



EXPORT_SYMBOL(fget_raw);



/*

 * Lightweight file lookup - no refcnt increment if fd table isn't shared.

 *

 * You can use this instead of fget if you satisfy all of the following

 * conditions:

 * 1) You must call fput_light before exiting the syscall and returning control

 *    to userspace (i.e. you cannot remember the returned struct file * after

 *    returning to userspace).

 * 2) You must not call filp_close on the returned struct file * in between

 *    calls to fget_light and fput_light.

 * 3) You must not clone the current task in between the calls to fget_light

 *    and fput_light.

 *

 * The fput_needed flag returned by fget_light should be passed to the

 * corresponding fput_light.

 */

struct file *fget_light(unsigned int fd, int *fput_needed)

{

	struct file *file;

	struct files_struct *files = current->files;



	*fput_needed = 0;

	if (atomic_read(&files->count) == 1) {

		file = fcheck_files(files, fd);

		if (file && (file->f_mode & FMODE_PATH))

			file = NULL;

	} else {

		rcu_read_lock();

		file = fcheck_files(files, fd);

		if (file) {

			if (!(file->f_mode & FMODE_PATH) &&

			    atomic_long_inc_not_zero(&file->f_count))

				*fput_needed = 1;

			else

				/* Didn't get the reference, someone's freed */

				file = NULL;

		}

		rcu_read_unlock();

	}



	return file;

}



struct file *fget_raw_light(unsigned int fd, int *fput_needed)

{

	struct file *file;

	struct files_struct *files = current->files;



	*fput_needed = 0;

	if (atomic_read(&files->count) == 1) {

		file = fcheck_files(files, fd);

	} else {

		rcu_read_lock();

		file = fcheck_files(files, fd);

		if (file) {

			if (atomic_long_inc_not_zero(&file->f_count))

				*fput_needed = 1;

			else

				/* Didn't get the reference, someone's freed */

				file = NULL;

		}

		rcu_read_unlock();

	}



	return file;

}

fs/file_table.c

+0 −106
Original line number Diff line number Diff line
@@ -339,112 +339,6 @@ void __fput_sync(struct file *file) 


EXPORT_SYMBOL(fput);



struct file *fget(unsigned int fd)

{

	struct file *file;

	struct files_struct *files = current->files;



	rcu_read_lock();

	file = fcheck_files(files, fd);

	if (file) {

		/* File object ref couldn't be taken */

		if (file->f_mode & FMODE_PATH ||

		    !atomic_long_inc_not_zero(&file->f_count))

			file = NULL;

	}

	rcu_read_unlock();



	return file;

}



EXPORT_SYMBOL(fget);



struct file *fget_raw(unsigned int fd)

{

	struct file *file;

	struct files_struct *files = current->files;



	rcu_read_lock();

	file = fcheck_files(files, fd);

	if (file) {

		/* File object ref couldn't be taken */

		if (!atomic_long_inc_not_zero(&file->f_count))

			file = NULL;

	}

	rcu_read_unlock();



	return file;

}



EXPORT_SYMBOL(fget_raw);



/*

 * Lightweight file lookup - no refcnt increment if fd table isn't shared.

 *

 * You can use this instead of fget if you satisfy all of the following

 * conditions:

 * 1) You must call fput_light before exiting the syscall and returning control

 *    to userspace (i.e. you cannot remember the returned struct file * after

 *    returning to userspace).

 * 2) You must not call filp_close on the returned struct file * in between

 *    calls to fget_light and fput_light.

 * 3) You must not clone the current task in between the calls to fget_light

 *    and fput_light.

 *

 * The fput_needed flag returned by fget_light should be passed to the

 * corresponding fput_light.

 */

struct file *fget_light(unsigned int fd, int *fput_needed)

{

	struct file *file;

	struct files_struct *files = current->files;



	*fput_needed = 0;

	if (atomic_read(&files->count) == 1) {

		file = fcheck_files(files, fd);

		if (file && (file->f_mode & FMODE_PATH))

			file = NULL;

	} else {

		rcu_read_lock();

		file = fcheck_files(files, fd);

		if (file) {

			if (!(file->f_mode & FMODE_PATH) &&

			    atomic_long_inc_not_zero(&file->f_count))

				*fput_needed = 1;

			else

				/* Didn't get the reference, someone's freed */

				file = NULL;

		}

		rcu_read_unlock();

	}



	return file;

}



struct file *fget_raw_light(unsigned int fd, int *fput_needed)

{

	struct file *file;

	struct files_struct *files = current->files;



	*fput_needed = 0;

	if (atomic_read(&files->count) == 1) {

		file = fcheck_files(files, fd);

	} else {

		rcu_read_lock();

		file = fcheck_files(files, fd);

		if (file) {

			if (atomic_long_inc_not_zero(&file->f_count))

				*fput_needed = 1;

			else

				/* Didn't get the reference, someone's freed */

				file = NULL;

		}

		rcu_read_unlock();

	}



	return file;

}



void put_filp(struct file *file)

{

	if (atomic_long_dec_and_test(&file->f_count)) {