Commit 85c8c3c1 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Song Liu
Browse files

md: factor out a mddev_alloc_unit helper from mddev_find 



Split out a self contained helper to find a free minor for the md
"unit" number.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarSong Liu <song@kernel.org>
parent f8ee34a9

drivers/md/md.c

+27 −20
Original line number Diff line number Diff line
@@ -745,6 +745,27 @@ static struct mddev *mddev_find_locked(dev_t unit) 
	return NULL;

}



/* find an unused unit number */

static dev_t mddev_alloc_unit(void)

{

	static int next_minor = 512;

	int start = next_minor;

	bool is_free = 0;

	dev_t dev = 0;



	while (!is_free) {

		dev = MKDEV(MD_MAJOR, next_minor);

		next_minor++;

		if (next_minor > MINORMASK)

			next_minor = 0;

		if (next_minor == start)

			return 0;		/* Oh dear, all in use. */

		is_free = !mddev_find_locked(dev);

	}



	return dev;

}



static struct mddev *mddev_find(dev_t unit)

{

	struct mddev *mddev;
@@ -787,27 +808,13 @@ static struct mddev *mddev_find_or_alloc(dev_t unit) 
			return new;

		}

	} else if (new) {

		/* find an unused unit number */

		static int next_minor = 512;

		int start = next_minor;

		int is_free = 0;

		int dev = 0;

		while (!is_free) {

			dev = MKDEV(MD_MAJOR, next_minor);

			next_minor++;

			if (next_minor > MINORMASK)

				next_minor = 0;

			if (next_minor == start) {

				/* Oh dear, all in use. */

		new->unit = mddev_alloc_unit();

		if (!new->unit) {

			spin_unlock(&all_mddevs_lock);

			kfree(new);

			return NULL;

		}



			is_free = !mddev_find_locked(dev);

		}

		new->unit = dev;

		new->md_minor = MINOR(dev);

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

		new->hold_active = UNTIL_STOP;

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

		spin_unlock(&all_mddevs_lock);