From: Alex Elder Date: Wed, 4 Apr 2012 18:35:44 +0000 (-0500) Subject: rbd: don't hold spinlock during messenger flush X-Git-Tag: v3.4.20~85 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=095cb2142dfb10daea5a3351ed9646d3178a6823;p=platform%2Fkernel%2Flinux-stable.git rbd: don't hold spinlock during messenger flush (cherry picked from commit cd9d9f5df6098c50726200d4185e9e8da32785b3) 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: Alex Elder Reviewed-by: Sage Weil Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c index 013c7a5..c1f7701 100644 --- a/drivers/block/rbd.c +++ b/drivers/block/rbd.c @@ -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; }