diff options
| author | Jianchao Wang <jianchao.w.wang@oracle.com> | 2018-02-12 20:54:46 +0800 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2018-03-26 08:53:43 -0600 |
| commit | 765cc031cddde40bdc279e8e2697571c7956c54e (patch) | |
| tree | 7d8beb4bcf2cf6fbe8cebdb600b3633158ce61e6 /drivers/nvme/host/multipath.c | |
| parent | 6f8e0d787e3727ed70116e3523f4ecb86887c000 (diff) | |
nvme: change namespaces_mutext to namespaces_rwsem
namespaces_mutext is used to synchronize the operations on ctrl
namespaces list. Most of the time, it is a read operation.
On the other hand, there are many interfaces in nvme core that
need this lock, such as nvme_wait_freeze, and even more interfaces
will be added. If we use mutex here, circular dependency could be
introduced easily. For example:
context A context B
nvme_xxx nvme_xxx
hold namespaces_mutext require namespaces_mutext
sync context B
So it is better to change it from mutex to rwsem.
Reviewed-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Jianchao Wang <jianchao.w.wang@oracle.com>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'drivers/nvme/host/multipath.c')
| -rw-r--r-- | drivers/nvme/host/multipath.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/nvme/host/multipath.c b/drivers/nvme/host/multipath.c index 7283d7149baf..affd67021b6f 100644 --- a/drivers/nvme/host/multipath.c +++ b/drivers/nvme/host/multipath.c @@ -44,12 +44,12 @@ void nvme_kick_requeue_lists(struct nvme_ctrl *ctrl) { struct nvme_ns *ns; - mutex_lock(&ctrl->namespaces_mutex); + down_read(&ctrl->namespaces_rwsem); list_for_each_entry(ns, &ctrl->namespaces, list) { if (ns->head->disk) kblockd_schedule_work(&ns->head->requeue_work); } - mutex_unlock(&ctrl->namespaces_mutex); + up_read(&ctrl->namespaces_rwsem); } static struct nvme_ns *__nvme_find_path(struct nvme_ns_head *head) |