From mboxrd@z Thu Jan 1 00:00:00 1970 From: keith.busch@intel.com (Keith Busch) Date: Tue, 17 May 2016 15:37:42 -0600 Subject: [PATCH] NVMe: Fix possible scheduling while atomic error Message-ID: <1463521062-16488-1-git-send-email-keith.busch@intel.com> Stopping a h/w queue could have scheduled the task to wait on cancelling work. This patch removes stopping the the delayed work so we can safely hold rcu_read_lock() while stopping h/w queues. Since blk-mq requeue work may restart the h/w queues during a reset, the nvme driver's queue_rq will stop them again if the driver receives a command during the reset window. Reported-by: Ming Lin [fixes 0bf77e9 nvme: switch to RCU freeing the namespace] Signed-off-by: Keith Busch --- drivers/nvme/host/core.c | 6 ++++-- drivers/nvme/host/pci.c | 6 ++++++ 2 files changed, 10 insertions(+), 2 deletions(-) diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c index 1a51584..1e05abf 100644 --- a/drivers/nvme/host/core.c +++ b/drivers/nvme/host/core.c @@ -1823,7 +1823,6 @@ void nvme_stop_queues(struct nvme_ctrl *ctrl) queue_flag_set(QUEUE_FLAG_STOPPED, ns->queue); spin_unlock_irq(ns->queue->queue_lock); - blk_mq_cancel_requeue_work(ns->queue); blk_mq_stop_hw_queues(ns->queue); } rcu_read_unlock(); @@ -1836,7 +1835,10 @@ void nvme_start_queues(struct nvme_ctrl *ctrl) rcu_read_lock(); list_for_each_entry_rcu(ns, &ctrl->namespaces, list) { - queue_flag_clear_unlocked(QUEUE_FLAG_STOPPED, ns->queue); + spin_lock_irq(ns->queue->queue_lock); + queue_flag_clear(QUEUE_FLAG_STOPPED, ns->queue); + spin_unlock_irq(ns->queue->queue_lock); + blk_mq_start_stopped_hw_queues(ns->queue, true); blk_mq_kick_requeue_list(ns->queue); } diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c index 8356813..9693629 100644 --- a/drivers/nvme/host/pci.c +++ b/drivers/nvme/host/pci.c @@ -609,6 +609,12 @@ static int nvme_queue_rq(struct blk_mq_hw_ctx *hctx, spin_unlock_irq(&nvmeq->q_lock); return BLK_MQ_RQ_QUEUE_OK; out: + if (ret == BLK_MQ_RQ_QUEUE_BUSY) { + spin_lock_irq(ns->queue->queue_lock); + if (blk_queue_stopped(req->q)) + blk_mq_stop_hw_queues(ns->queue); + spin_unlock_irq(ns->queue->queue_lock); + } nvme_free_iod(dev, req); return ret; } -- 2.7.2