PCI/vga: Use hotplug-safe pci_get_domain_bus_and_slot()

Following code has a race window between pci_find_bus() and pci_get_slot()
if PCI hotplug operation happens between them which removes the pci_bus.
So use PCI hotplug safe interface pci_get_domain_bus_and_slot() instead,
which also reduces code complexity.

    struct pci_bus *pci_bus = pci_find_bus(domain, busno);
    struct pci_dev *pci_dev = pci_get_slot(pci_bus, devfn);

Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

diff --git a/drivers/gpu/vga/vgaarb.c b/drivers/gpu/vga/vgaarb.c
index 3df8fc0ec01a93ab95883139b2c3f531b72e5934..b6852b776931e8c8482c0c8754951708ca99954f 100644 (file)
--- a/drivers/gpu/vga/vgaarb.c
+++ b/drivers/gpu/vga/vgaarb.c
@@ -1066,7 +1066,6 @@ static ssize_t vga_arb_write(struct file *file, const char __user * buf,
                }
 
        } else if (strncmp(curr_pos, "target ", 7) == 0) {
-               struct pci_bus *pbus;
                unsigned int domain, bus, devfn;
                struct vga_device *vgadev;
 
@@ -1085,19 +1084,11 @@ static ssize_t vga_arb_write(struct file *file, const char __user * buf,
                        pr_debug("vgaarb: %s ==> %x:%x:%x.%x\n", curr_pos,
                                domain, bus, PCI_SLOT(devfn), PCI_FUNC(devfn));
 
-                       pbus = pci_find_bus(domain, bus);
-                       pr_debug("vgaarb: pbus %p\n", pbus);
-                       if (pbus == NULL) {
-                               pr_err("vgaarb: invalid PCI domain and/or bus address %x:%x\n",
-                                       domain, bus);
-                               ret_val = -ENODEV;
-                               goto done;
-                       }
-                       pdev = pci_get_slot(pbus, devfn);
+                       pdev = pci_get_domain_bus_and_slot(domain, bus, devfn);
                        pr_debug("vgaarb: pdev %p\n", pdev);
                        if (!pdev) {
-                               pr_err("vgaarb: invalid PCI address %x:%x\n",
-                                       bus, devfn);
+                               pr_err("vgaarb: invalid PCI address %x:%x:%x\n",
+                                       domain, bus, devfn);
                                ret_val = -ENODEV;
                                goto done;
                        }