From 095cb2142dfb10daea5a3351ed9646d3178a6823 Mon Sep 17 00:00:00 2001 From: Alex Elder Date: Wed, 4 Apr 2012 13:35:44 -0500 Subject: [PATCH] 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 --- drivers/block/rbd.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) 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; } -- 2.7.4