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 <keith.busch@intel.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index a363fec..212f7e0 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);
@@ -960,6 +965,16 @@ static enum blk_eh_timer_return nvme_timeout(struct request *req, bool reserved)
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
* cancellation error. All outstanding requests are completed on