Commit d144fe6f authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Song Liu
Browse files

md: refactor mddev_find_or_alloc 



Allocate the new mddev first speculatively, which greatly simplifies
the code flow.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarSong Liu <song@kernel.org>
parent 85c8c3c1

drivers/md/md.c

+24 −36
Original line number Diff line number Diff line
@@ -784,57 +784,45 @@ static struct mddev *mddev_find(dev_t unit) 


static struct mddev *mddev_find_or_alloc(dev_t unit)

{

	struct mddev *mddev, *new = NULL;

	struct mddev *mddev = NULL, *new;



	if (unit && MAJOR(unit) != MD_MAJOR)

		unit &= ~((1 << MdpMinorShift) - 1);



 retry:

	spin_lock(&all_mddevs_lock);

	new = kzalloc(sizeof(*new), GFP_KERNEL);

	if (!new)

		return NULL;

	mddev_init(new);



	spin_lock(&all_mddevs_lock);

	if (unit) {

		mddev = mddev_find_locked(unit);

		if (mddev) {

			mddev_get(mddev);

			spin_unlock(&all_mddevs_lock);

			kfree(new);

			return mddev;

			goto out_free_new;

		}



		if (new) {

			list_add(&new->all_mddevs, &all_mddevs);

			spin_unlock(&all_mddevs_lock);

		new->unit = unit;

		if (MAJOR(unit) == MD_MAJOR)

			new->md_minor = MINOR(unit);

		else

			new->md_minor = MINOR(unit) >> MdpMinorShift;

		new->hold_active = UNTIL_IOCTL;

			return new;

		}

	} else if (new) {

	} else {

		new->unit = mddev_alloc_unit();

		if (!new->unit) {

			spin_unlock(&all_mddevs_lock);

			kfree(new);

			return NULL;

		}

		if (!new->unit)

			goto out_free_new;

		new->md_minor = MINOR(new->unit);

		new->hold_active = UNTIL_STOP;

	}



	list_add(&new->all_mddevs, &all_mddevs);

	spin_unlock(&all_mddevs_lock);

	return new;

	}

out_free_new:

	spin_unlock(&all_mddevs_lock);



	new = kzalloc(sizeof(*new), GFP_KERNEL);

	if (!new)

		return NULL;



	new->unit = unit;

	if (MAJOR(unit) == MD_MAJOR)

		new->md_minor = MINOR(unit);

	else

		new->md_minor = MINOR(unit) >> MdpMinorShift;



	mddev_init(new);



	goto retry;

	kfree(new);

	return mddev;

}



static struct attribute_group md_redundancy_group;