| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.20 53/88] nvme-rdma: fix timeout handler | Date | Mon, 4 Mar 2019 09:22:36 +0100 |
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4.20-stable review patch. If anyone has any objections, please let me know.
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[ Upstream commit 4c174e6366746ae8d49f9cc409f728eebb7a9ac9 ]
Currently, we have several problems with the timeout handler: 1. If we timeout on the controller establishment flow, we will hang because we don't execute the error recovery (and we shouldn't because the create_ctrl flow needs to fail and cleanup on its own) 2. We might also hang if we get a disconnet on a queue while the controller is already deleting. This racy flow can cause the controller disable/shutdown admin command to hang.
We cannot complete a timed out request from the timeout handler without mutual exclusion from the teardown flow (e.g. nvme_rdma_error_recovery_work). So we serialize it in the timeout handler and teardown io and admin queues to guarantee that no one races with us from completing the request.
Reported-by: Jaesoo Lee <jalee@purestorage.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Sagi Grimberg <sagi@grimberg.me> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org> --- drivers/nvme/host/rdma.c | 26 ++++++++++++++++++-------- 1 file changed, 18 insertions(+), 8 deletions(-)
diff --git a/drivers/nvme/host/rdma.c b/drivers/nvme/host/rdma.c index ab6ec7295bf90..6e24b20304b53 100644 --- a/drivers/nvme/host/rdma.c +++ b/drivers/nvme/host/rdma.c @@ -1679,18 +1679,28 @@ static enum blk_eh_timer_return nvme_rdma_timeout(struct request *rq, bool reserved) { struct nvme_rdma_request *req = blk_mq_rq_to_pdu(rq); + struct nvme_rdma_queue *queue = req->queue; + struct nvme_rdma_ctrl *ctrl = queue->ctrl; - dev_warn(req->queue->ctrl->ctrl.device, - "I/O %d QID %d timeout, reset controller\n", - rq->tag, nvme_rdma_queue_idx(req->queue)); + dev_warn(ctrl->ctrl.device, "I/O %d QID %d timeout\n", + rq->tag, nvme_rdma_queue_idx(queue)); - /* queue error recovery */ - nvme_rdma_error_recovery(req->queue->ctrl); + if (ctrl->ctrl.state != NVME_CTRL_LIVE) { + /* + * Teardown immediately if controller times out while starting + * or we are already started error recovery. all outstanding + * requests are completed on shutdown, so we return BLK_EH_DONE. + */ + flush_work(&ctrl->err_work); + nvme_rdma_teardown_io_queues(ctrl, false); + nvme_rdma_teardown_admin_queue(ctrl, false); + return BLK_EH_DONE; + } - /* fail with DNR on cmd timeout */ - nvme_req(rq)->status = NVME_SC_ABORT_REQ | NVME_SC_DNR; + dev_warn(ctrl->ctrl.device, "starting error recovery\n"); + nvme_rdma_error_recovery(ctrl); - return BLK_EH_DONE; + return BLK_EH_RESET_TIMER; } static blk_status_t nvme_rdma_queue_rq(struct blk_mq_hw_ctx *hctx, -- 2.19.1
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