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>

1 files changed, 3 insertions, 12 deletions

diff --git a/drivers/gpu/vga/vgaarb.c b/drivers/gpu/vga/vgaarb.c
index 3df8fc0ec01a..b6852b776931 100644
--- 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;
                         }