nvme: don't call blk_mq_{,un}quiesce_tagset when ctrl->tagset is NULL

The NVMe drivers support a mode where no tagset is allocated for the I/O
queues and only the admin queue is usable.  In that case ctrl->tagset is
NULL and we must not call the block per-tagset quiesce helpers that
dereference it.

Fixes: 98d81f0df70c ("nvme: use blk_mq_[un]quiesce_tagset")
Reported-by: Gerd Bayer <gbayer@linux.ibm.com>
Reported-by: Chao Leng <lengchao@huawei.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chao Leng <lengchao@huawei.com>

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 3195ae1..fd2e26c 100644 (file)
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -5215,6 +5215,8 @@ EXPORT_SYMBOL_GPL(nvme_start_freeze);
 
 void nvme_quiesce_io_queues(struct nvme_ctrl *ctrl)
 {
+       if (!ctrl->tagset)
+               return;
        if (!test_and_set_bit(NVME_CTRL_STOPPED, &ctrl->flags))
                blk_mq_quiesce_tagset(ctrl->tagset);
        else
@@ -5224,6 +5226,8 @@ EXPORT_SYMBOL_GPL(nvme_quiesce_io_queues);
 
 void nvme_unquiesce_io_queues(struct nvme_ctrl *ctrl)
 {
+       if (!ctrl->tagset)
+               return;
        if (test_and_clear_bit(NVME_CTRL_STOPPED, &ctrl->flags))
                blk_mq_unquiesce_tagset(ctrl->tagset);
 }