um-virt-pci: Make max delay configurable

There is a hard coded maximum time for which the driver busy-loops
waiting for a response from the virtio device.  This default time may be
too short for some systems, so make it a module parameter so that it can
be set via the kernel command line.

Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

diff --git a/arch/um/drivers/virt-pci.c b/arch/um/drivers/virt-pci.c
index 6884e1b..0aa71c0 100644 (file)
--- a/arch/um/drivers/virt-pci.c
+++ b/arch/um/drivers/virt-pci.c
@@ -54,7 +54,8 @@ static struct irq_domain *um_pci_inner_domain;
 static struct irq_domain *um_pci_msi_domain;
 static unsigned long um_pci_msi_used[BITS_TO_LONGS(MAX_MSI_VECTORS)];
 
-#define UM_VIRT_PCI_MAXDELAY 40000
+static unsigned int um_pci_max_delay_us = 40000;
+module_param_named(max_delay_us, um_pci_max_delay_us, uint, 0644);
 
 struct um_pci_message_buffer {
        struct virtio_pcidev_msg hdr;
@@ -155,7 +156,7 @@ static int um_pci_send_cmd(struct um_pci_device *dev,
                        kfree(completed);
 
                if (WARN_ONCE(virtqueue_is_broken(dev->cmd_vq) ||
-                             ++delay_count > UM_VIRT_PCI_MAXDELAY,
+                             ++delay_count > um_pci_max_delay_us,
                              "um virt-pci delay: %d", delay_count)) {
                        ret = -EIO;
                        break;