uio/uio_pci_generic: don't fail probe if pdev->irq == NULL

Some userspace drivers and frameworks only poll and do not
require interrupts to be available and enabled on the
PCI device.  So remove the requirement that an IRQ is
assigned.  If an IRQ is not assigned and a userspace
driver tries to read()/write(), the generic uio
framework will just return -EIO.

This allows binding uio_pci_generic to devices which
cannot get an IRQ assigned, such as an NVMe controller
behind Intel Volume Management Device (VMD), since VMD
does not support INTx interrupts.

Signed-off-by: Jim Harris <james.r.harris@intel.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/uio/uio_pci_generic.c b/drivers/uio/uio_pci_generic.c
index d0b508b68f3c3e4969bf46036510255d01ae7dd9..a56fdf972dbe5906b9d6368fbf84275c734f212e 100644 (file)
--- a/drivers/uio/uio_pci_generic.c
+++ b/drivers/uio/uio_pci_generic.c
@@ -66,14 +66,7 @@ static int probe(struct pci_dev *pdev,
                return err;
        }
 
-       if (!pdev->irq) {
-               dev_warn(&pdev->dev, "No IRQ assigned to device: "
-                        "no support for interrupts?\n");
-               pci_disable_device(pdev);
-               return -ENODEV;
-       }
-
-       if (!pci_intx_mask_supported(pdev)) {
+       if (pdev->irq && !pci_intx_mask_supported(pdev)) {
                err = -ENODEV;
                goto err_verify;
        }
@@ -86,10 +79,15 @@ static int probe(struct pci_dev *pdev,
 
        gdev->info.name = "uio_pci_generic";
        gdev->info.version = DRIVER_VERSION;
-       gdev->info.irq = pdev->irq;
-       gdev->info.irq_flags = IRQF_SHARED;
-       gdev->info.handler = irqhandler;
        gdev->pdev = pdev;
+       if (pdev->irq) {
+               gdev->info.irq = pdev->irq;
+               gdev->info.irq_flags = IRQF_SHARED;
+               gdev->info.handler = irqhandler;
+       } else {
+               dev_warn(&pdev->dev, "No IRQ assigned to device: "
+                        "no support for interrupts?\n");
+       }
 
        err = uio_register_device(&pdev->dev, &gdev->info);
        if (err)