Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit cd9d9f5d authored by Alex Elder's avatar Alex Elder
Browse files

rbd: don't hold spinlock during messenger flush 



A recent change made changes to the rbd_client_list be protected by
a spinlock.  Unfortunately in rbd_put_client(), the lock is taken
before possibly dropping the last reference to an rbd_client, and on
the last reference that eventually calls flush_workqueue() which can
sleep.

The problem was flagged by a debug spinlock warning:
    BUG: spinlock wrong CPU on CPU#3, rbd/27814

The solution is to move the spinlock acquisition and release inside
rbd_client_release(), which is the spot where it's really needed for
protecting the removal of the rbd_client from the client list.

Signed-off-by: default avatarAlex Elder <elder@dreamhost.com>
Reviewed-by: default avatarSage Weil <sage@newdream.net>
parent c666601a

drivers/block/rbd.c

+2 −2
Original line number Diff line number Diff line
@@ -450,7 +450,9 @@ static void rbd_client_release(struct kref *kref) 
	struct rbd_client *rbdc = container_of(kref, struct rbd_client, kref);



	dout("rbd_release_client %p\n", rbdc);

	spin_lock(&rbd_client_list_lock);

	list_del(&rbdc->node);

	spin_unlock(&rbd_client_list_lock);



	ceph_destroy_client(rbdc->client);

	kfree(rbdc->rbd_opts);
@@ -463,9 +465,7 @@ static void rbd_client_release(struct kref *kref) 
 */

static void rbd_put_client(struct rbd_device *rbd_dev)

{

	spin_lock(&rbd_client_list_lock);

	kref_put(&rbd_dev->rbd_client->kref, rbd_client_release);

	spin_unlock(&rbd_client_list_lock);

	rbd_dev->rbd_client = NULL;

}