[PATCH 4.9 081/240] md: factor out a mddev_find_locked helper from mddev_find

Greg Kroah-Hartman
2021-05-20T11:09:06Z

From: Christoph Hellwig <hch@lst.de>

commit 8b57251f9a91f5e5a599de7549915d2d226cc3af upstream.

Factor out a self-contained helper to just lookup a mddev by the dev_t
"unit".

Cc: stable@vger.kernel.org
Reviewed-by: Heming Zhao <heming.zhao@suse.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Song Liu <song@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/md/md.c | 32 +++++++++++++++++++-------------
1 file changed, 19 insertions(+), 13 deletions(-)

--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -508,6 +508,17 @@ void mddev_init(struct mddev *mddev)
}
EXPORT_SYMBOL_GPL(mddev_init);

+static struct mddev *mddev_find_locked(dev_t unit)
+{
+ struct mddev *mddev;
+
+ list_for_each_entry(mddev, &all_mddevs, all_mddevs)
+ if (mddev->unit == unit)
+ return mddev;
+
+ return NULL;
+}
+
static struct mddev *mddev_find(dev_t unit)
{
struct mddev *mddev, *new = NULL;
@@ -519,13 +530,13 @@ static struct mddev *mddev_find(dev_t un
spin_lock(&all_mddevs_lock);

if (unit) {
- list_for_each_entry(mddev, &all_mddevs, all_mddevs)
- if (mddev->unit == unit) {
- mddev_get(mddev);
- spin_unlock(&all_mddevs_lock);
- kfree(new);
- return mddev;
- }
+ mddev = mddev_find_locked(unit);
+ if (mddev) {
+ mddev_get(mddev);
+ spin_unlock(&all_mddevs_lock);
+ kfree(new);
+ return mddev;
+ }

if (new) {
list_add(&new->all_mddevs, &all_mddevs);
@@ -551,12 +562,7 @@ static struct mddev *mddev_find(dev_t un
return NULL;
}

- is_free = 1;
- list_for_each_entry(mddev, &all_mddevs, all_mddevs)
- if (mddev->unit == dev) {
- is_free = 0;
- break;
- }
+ is_free = !mddev_find_locked(dev);
}
new->unit = dev;
new->md_minor = MINOR(dev);