Commit 830cf3f7 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by openeuler-sync-bot
Browse files

md: factor out a mddev_alloc_unit helper from mddev_find 

mainline inclusion
from mainline-v5.13-rc1
commit 85c8c3c1
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I8O6NL
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=85c8c3c1f8d9e31f626c93435dd91c2f85603e07



-------------------------------------------------

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>
Signed-off-by: default avatarLi Lingfeng <lilingfeng3@huawei.com>
(cherry picked from commit 38f910c8)
parent 3b063171

drivers/md/md.c

+27 −20
Original line number Diff line number Diff line
@@ -723,6 +723,27 @@ 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;
@@ -765,27 +786,13 @@ 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);