There's a typical usage pattern to search a PCI device under a specific
PCI bus (domian, busno) as below:
struct pci_bus *pci_bus = pci_find_bus(domain, busno);
struct pci_dev *pci_dev = pci_get_slot(pci_bus, devfn);

The above code has a race window between pci_find_bus() and pci_get_slot()
if PCI hotplug operations happen 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.

Signed-off-by: Jiang Liu <liu...@gmail.com>
---
 arch/ia64/sn/kernel/io_common.c      |    4 +---
 drivers/gpu/vga/vgaarb.c             |   15 +++------------
 drivers/pci/hotplug/cpcihp_generic.c |    8 ++------
 drivers/pci/iov.c                    |    8 ++------
 drivers/pci/xen-pcifront.c           |   10 ++--------
 5 files changed, 10 insertions(+), 35 deletions(-)

diff --git a/arch/ia64/sn/kernel/io_common.c b/arch/ia64/sn/kernel/io_common.c
index fbb5f2f..8630875 100644
--- a/arch/ia64/sn/kernel/io_common.c
+++ b/arch/ia64/sn/kernel/io_common.c
@@ -229,7 +229,6 @@ void sn_pci_fixup_slot(struct pci_dev *dev, struct 
pcidev_info *pcidev_info,
 {
        int segment = pci_domain_nr(dev->bus);
        struct pcibus_bussoft *bs;
-       struct pci_bus *host_pci_bus;
        struct pci_dev *host_pci_dev;
        unsigned int bus_no, devfn;
 
@@ -245,8 +244,7 @@ void sn_pci_fixup_slot(struct pci_dev *dev, struct 
pcidev_info *pcidev_info,
 
        bus_no = (pcidev_info->pdi_slot_host_handle >> 32) & 0xff;
        devfn = pcidev_info->pdi_slot_host_handle & 0xffffffff;
-       host_pci_bus = pci_find_bus(segment, bus_no);
-       host_pci_dev = pci_get_slot(host_pci_bus, devfn);
+       host_pci_dev = pci_get_domain_bus_and_slot(segment, bus_no, devfn);
 
        pcidev_info->host_pci_dev = host_pci_dev;
        pcidev_info->pdi_linux_pcidev = dev;
diff --git a/drivers/gpu/vga/vgaarb.c b/drivers/gpu/vga/vgaarb.c
index 3df8fc0..b6852b7 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;
                        }
diff --git a/drivers/pci/hotplug/cpcihp_generic.c 
b/drivers/pci/hotplug/cpcihp_generic.c
index 81af764..a6a71c4 100644
--- a/drivers/pci/hotplug/cpcihp_generic.c
+++ b/drivers/pci/hotplug/cpcihp_generic.c
@@ -154,12 +154,8 @@ static int __init cpcihp_generic_init(void)
        if(!r)
                return -EBUSY;
 
-       bus = pci_find_bus(0, bridge_busnr);
-       if (!bus) {
-               err("Invalid bus number %d", bridge_busnr);
-               return -EINVAL;
-       }
-       dev = pci_get_slot(bus, PCI_DEVFN(bridge_slot, 0));
+       dev = pci_get_domain_bus_and_slot(0, bridge_busnr,
+                                         PCI_DEVFN(bridge_slot, 0));
        if(!dev || dev->hdr_type != PCI_HEADER_TYPE_BRIDGE) {
                err("Invalid bridge device %s", bridge);
                pci_dev_put(dev);
diff --git a/drivers/pci/iov.c b/drivers/pci/iov.c
index 74bbaf8..c7d2969 100644
--- a/drivers/pci/iov.c
+++ b/drivers/pci/iov.c
@@ -152,15 +152,11 @@ failed1:
 static void virtfn_remove(struct pci_dev *dev, int id, int reset)
 {
        char buf[VIRTFN_ID_LEN];
-       struct pci_bus *bus;
        struct pci_dev *virtfn;
        struct pci_sriov *iov = dev->sriov;
 
-       bus = pci_find_bus(pci_domain_nr(dev->bus), virtfn_bus(dev, id));
-       if (!bus)
-               return;
-
-       virtfn = pci_get_slot(bus, virtfn_devfn(dev, id));
+       virtfn = pci_get_domain_bus_and_slot(pci_domain_nr(dev->bus),
+                       virtfn_bus(dev, id), virtfn_devfn(dev, id));
        if (!virtfn)
                return;
 
diff --git a/drivers/pci/xen-pcifront.c b/drivers/pci/xen-pcifront.c
index d6cc62c..def8d0b 100644
--- a/drivers/pci/xen-pcifront.c
+++ b/drivers/pci/xen-pcifront.c
@@ -982,7 +982,6 @@ static int pcifront_detach_devices(struct pcifront_device 
*pdev)
        int err = 0;
        int i, num_devs;
        unsigned int domain, bus, slot, func;
-       struct pci_bus *pci_bus;
        struct pci_dev *pci_dev;
        char str[64];
 
@@ -1032,13 +1031,8 @@ static int pcifront_detach_devices(struct 
pcifront_device *pdev)
                        goto out;
                }
 
-               pci_bus = pci_find_bus(domain, bus);
-               if (!pci_bus) {
-                       dev_dbg(&pdev->xdev->dev, "Cannot get bus %04x:%02x\n",
-                               domain, bus);
-                       continue;
-               }
-               pci_dev = pci_get_slot(pci_bus, PCI_DEVFN(slot, func));
+               pci_dev = pci_get_domain_bus_and_slot(domain, bus,
+                               PCI_DEVFN(slot, func));
                if (!pci_dev) {
                        dev_dbg(&pdev->xdev->dev,
                                "Cannot get PCI device %04x:%02x:%02x.%d\n",
-- 
1.7.9.5

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