From 7776db1ccc123d5944a8c170c9c45f7e91d49643 Mon Sep 17 00:00:00 2001 From: Keith Busch Date: Fri, 24 Feb 2017 17:59:28 -0500 Subject: [PATCH] nvme/pci: Poll CQ on timeout If an IO timeout occurs, it's helpful to know if the controller did not post a completion or the driver missed an interrupt. While we never expect the latter, this patch will make it possible to tell the difference so we don't have to guess. Signed-off-by: Keith Busch Signed-off-by: Christoph Hellwig Tested-by: Johannes Thumshirn Reviewed-by: Johannes Thumshirn --- drivers/nvme/host/pci.c | 21 ++++++++++++++++++--- 1 file changed, 18 insertions(+), 3 deletions(-) diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c index a363fecb8d82..212f7e0db84f 100644 --- a/drivers/nvme/host/pci.c +++ b/drivers/nvme/host/pci.c @@ -846,10 +846,8 @@ static irqreturn_t nvme_irq_check(int irq, void *data) return IRQ_NONE; } -static int nvme_poll(struct blk_mq_hw_ctx *hctx, unsigned int tag) +static int __nvme_poll(struct nvme_queue *nvmeq, unsigned int tag) { - struct nvme_queue *nvmeq = hctx->driver_data; - if (nvme_cqe_valid(nvmeq, nvmeq->cq_head, nvmeq->cq_phase)) { spin_lock_irq(&nvmeq->q_lock); __nvme_process_cq(nvmeq, &tag); @@ -862,6 +860,13 @@ static int nvme_poll(struct blk_mq_hw_ctx *hctx, unsigned int tag) return 0; } +static int nvme_poll(struct blk_mq_hw_ctx *hctx, unsigned int tag) +{ + struct nvme_queue *nvmeq = hctx->driver_data; + + return __nvme_poll(nvmeq, tag); +} + static void nvme_pci_submit_async_event(struct nvme_ctrl *ctrl, int aer_idx) { struct nvme_dev *dev = to_nvme_dev(ctrl); @@ -959,6 +964,16 @@ static enum blk_eh_timer_return nvme_timeout(struct request *req, bool reserved) struct request *abort_req; struct nvme_command cmd; + /* + * Did we miss an interrupt? + */ + if (__nvme_poll(nvmeq, req->tag)) { + dev_warn(dev->ctrl.device, + "I/O %d QID %d timeout, completion polled\n", + req->tag, nvmeq->qid); + return BLK_EH_HANDLED; + } + /* * Shutdown immediately if controller times out while starting. The * reset work will see the pci device disabled when it gets the forced -- 2.20.1