NVMe: make setup work for devices that don't do INTx

The setup/probe part currently relies on INTx being there and
working, that's not always the case. For devices that don't
advertise INTx, enable a single MSIx vector early on and disable
it again before we ask for our full range of queue vecs.

Acked-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

diff --git a/drivers/block/nvme-core.c b/drivers/block/nvme-core.c
index 677d7b9ff454dca2c3cf97545dc3ed43830c9c7a..9310fe51382e1e497af93ce22fdbafef6bbbad09 100644 (file)
--- a/drivers/block/nvme-core.c
+++ b/drivers/block/nvme-core.c
@@ -1998,6 +1998,13 @@ static int nvme_setup_io_queues(struct nvme_dev *dev)
        /* Deregister the admin queue's interrupt */
        free_irq(dev->entry[0].vector, adminq);
 
+       /*
+        * If we enable msix early due to not intx, disable it again before
+        * setting up the full range we need.
+        */
+       if (!pdev->irq)
+               pci_disable_msix(pdev);
+
        for (i = 0; i < nr_io_queues; i++)
                dev->entry[i].entry = i;
        vecs = pci_enable_msix_range(pdev, dev->entry, 1, nr_io_queues);
@@ -2150,10 +2157,22 @@ static int nvme_dev_map(struct nvme_dev *dev)
        dev->bar = ioremap(pci_resource_start(pdev, 0), 8192);
        if (!dev->bar)
                goto disable;
+
        if (readl(&dev->bar->csts) == -1) {
                result = -ENODEV;
                goto unmap;
        }
+
+       /*
+        * Some devices don't advertse INTx interrupts, pre-enable a single
+        * MSIX vec for setup. We'll adjust this later.
+        */
+       if (!pdev->irq) {
+               result = pci_enable_msix(pdev, dev->entry, 1);
+               if (result < 0)
+                       goto unmap;
+       }
+
        cap = readq(&dev->bar->cap);
        dev->q_depth = min_t(int, NVME_CAP_MQES(cap) + 1, NVME_Q_DEPTH);
        dev->db_stride = 1 << NVME_CAP_STRIDE(cap);