Commit 4149be7b authored by Kuniyuki Iwashima's avatar Kuniyuki Iwashima Committed by Jeff Layton
Browse files

fs/lock: Don't allocate file_lock in flock_make_lock(). 



Two functions, flock syscall and locks_remove_flock(), call
flock_make_lock().  It allocates struct file_lock from slab
cache if its argument fl is NULL.

When we call flock syscall, we pass NULL to allocate memory
for struct file_lock.  However, we always free it at the end
by locks_free_lock().  We need not allocate it and instead
should use a local variable as locks_remove_flock() does.

Also, the validation for flock_translate_cmd() is not necessary
for locks_remove_flock().  So we move the part to flock syscall
and make flock_make_lock() return nothing.

Signed-off-by: default avatarKuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: default avatarChuck Lever <chuck.lever@oracle.com>
Signed-off-by: default avatarJeff Layton <jlayton@kernel.org>
parent ff699273

fs/locks.c

+15 −31
Original line number Diff line number Diff line
@@ -425,21 +425,9 @@ static inline int flock_translate_cmd(int cmd) { 
}



/* Fill in a file_lock structure with an appropriate FLOCK lock. */

static struct file_lock *

flock_make_lock(struct file *filp, unsigned int cmd, struct file_lock *fl)

static void flock_make_lock(struct file *filp, struct file_lock *fl, int type)

{

	int type = flock_translate_cmd(cmd);



	if (type < 0)

		return ERR_PTR(type);



	if (fl == NULL) {

		fl = locks_alloc_lock();

		if (fl == NULL)

			return ERR_PTR(-ENOMEM);

	} else {

	locks_init_lock(fl);

	}



	fl->fl_file = filp;

	fl->fl_owner = filp;
@@ -447,8 +435,6 @@ flock_make_lock(struct file *filp, unsigned int cmd, struct file_lock *fl) 
	fl->fl_flags = FL_FLOCK;

	fl->fl_type = type;

	fl->fl_end = OFFSET_MAX;



	return fl;

}



static int assign_type(struct file_lock *fl, long type)
@@ -2097,10 +2083,9 @@ EXPORT_SYMBOL(locks_lock_inode_wait); 
 */

SYSCALL_DEFINE2(flock, unsigned int, fd, unsigned int, cmd)

{

	int can_sleep, error, unlock, type;

	struct fd f = fdget(fd);

	struct file_lock *lock;

	int can_sleep, unlock;

	int error;

	struct file_lock fl;



	error = -EBADF;

	if (!f.file)
@@ -2127,28 +2112,27 @@ SYSCALL_DEFINE2(flock, unsigned int, fd, unsigned int, cmd) 
		goto out_putf;

	}



	lock = flock_make_lock(f.file, cmd, NULL);

	if (IS_ERR(lock)) {

		error = PTR_ERR(lock);

	type = flock_translate_cmd(cmd);

	if (type < 0) {

		error = type;

		goto out_putf;

	}



	flock_make_lock(f.file, &fl, type);



	if (can_sleep)

		lock->fl_flags |= FL_SLEEP;

		fl.fl_flags |= FL_SLEEP;



	error = security_file_lock(f.file, lock->fl_type);

	error = security_file_lock(f.file, fl.fl_type);

	if (error)

		goto out_free;

		goto out_putf;



	if (f.file->f_op->flock)

		error = f.file->f_op->flock(f.file,

					  (can_sleep) ? F_SETLKW : F_SETLK,

					  lock);

					    &fl);

	else

		error = locks_lock_file_wait(f.file, lock);



 out_free:

	locks_free_lock(lock);

		error = locks_lock_file_wait(f.file, &fl);



 out_putf:

	fdput(f);
@@ -2614,7 +2598,7 @@ locks_remove_flock(struct file *filp, struct file_lock_context *flctx) 
	if (list_empty(&flctx->flc_flock))

		return;



	flock_make_lock(filp, LOCK_UN, &fl);

	flock_make_lock(filp, &fl, F_UNLCK);

	fl.fl_flags |= FL_CLOSE;



	if (filp->f_op->flock)