[PATCH] pcnet32: Use pci_resource_len to validate PCI resource

[Guenter Roeck]

pci_resource_start() is not a good indicator to determine if a PCI
resource exists or not, since the resource may start at address 0.
This is seen when trying to instantiate the driver in qemu for riscv32
or riscv64.

pci 0000:00:01.0: reg 0x10: [io  0x0000-0x001f]
pci 0000:00:01.0: reg 0x14: [mem 0x00000000-0x0000001f]
...
pcnet32: card has no PCI IO resources, aborting

Use pci_resouce_len() instead.

Signed-off-by: Guenter Roeck <li...@roeck-us.net>
---
 drivers/net/ethernet/amd/pcnet32.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/amd/pcnet32.c 
b/drivers/net/ethernet/amd/pcnet32.c
index 187b0b9a6e1d..f78daba60b35 100644
--- a/drivers/net/ethernet/amd/pcnet32.c
+++ b/drivers/net/ethernet/amd/pcnet32.c
@@ -1534,8 +1534,7 @@ pcnet32_probe_pci(struct pci_dev *pdev, const struct 
pci_device_id *ent)
        }
        pci_set_master(pdev);
 
-       ioaddr = pci_resource_start(pdev, 0);
-       if (!ioaddr) {
+       if (!pci_resource_len(pdev, 0)) {
                if (pcnet32_debug & NETIF_MSG_PROBE)
                        pr_err("card has no PCI IO resources, aborting\n");
                err = -ENODEV;
@@ -1548,6 +1547,8 @@ pcnet32_probe_pci(struct pci_dev *pdev, const struct 
pci_device_id *ent)
                        pr_err("architecture does not support 32bit PCI 
busmaster DMA\n");
                goto err_disable_dev;
        }
+
+       ioaddr = pci_resource_start(pdev, 0);
        if (!request_region(ioaddr, PCNET32_TOTAL_SIZE, "pcnet32_probe_pci")) {
                if (pcnet32_debug & NETIF_MSG_PROBE)
                        pr_err("io address range already allocated\n");
-- 
2.17.1