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Date: Wed, 8 Aug 2012 00:10:41 +0800
From: Jiang Liu <liuj97@...il.com>
To: Bjorn Helgaas <bhelgaas@...gle.com>,
Don Dutile <ddutile@...hat.com>,
Yinghai Lu <yinghai@...nel.org>,
Greg KH <gregkh@...uxfoundation.org>,
Kenji Kaneshige <kaneshige.kenji@...fujitsu.com>
Cc: Jiang Liu <jiang.liu@...wei.com>,
Taku Izumi <izumi.taku@...fujitsu.com>,
"Rafael J . Wysocki" <rjw@...k.pl>,
Yijing Wang <wangyijing@...wei.com>,
Xinwei Hu <huxinwei@...wei.com>, linux-kernel@...r.kernel.org,
linux-pci@...r.kernel.org, Jiang Liu <liuj97@...il.com>
Subject: [RFC PATCH v1 01/22] PCI: use pci_get_domain_bus_and_slot() to avoid race conditions
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 <liuj97@...il.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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