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From: Jiang Liu <liuj97@gmail.com>
To: Bjorn Helgaas <bhelgaas@google.com>, Dave Airlie <airlied@redhat.com>
Cc: Jiang Liu <jiang.liu@huawei.com>, Don Dutile <ddutile@redhat.com>,
	Yinghai Lu <yinghai@kernel.org>,
	Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>,
	Yijing Wang <wangyijing@huawei.com>,
	linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org
Subject: [PATCH 2/5] PCI/vga: simplify code by hotplug safe pci_get_domain_bus_and_slot()
Date: Tue, 28 Aug 2012 23:43:55 +0800	[thread overview]
Message-ID: <1346168638-32724-3-git-send-email-jiang.liu@huawei.com> (raw)
In-Reply-To: <1346168638-32724-1-git-send-email-jiang.liu@huawei.com>

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>
---
 drivers/gpu/vga/vgaarb.c |   15 +++------------
 1 file changed, 3 insertions(+), 12 deletions(-)

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;
 			}
-- 
1.7.9.5


  parent reply	other threads:[~2012-08-28 15:43 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-08-28 15:43 [PATCH 0/5] Simplify code by using hotplug safe pci_get_domain_bus_and_slot() Jiang Liu
2012-08-28 15:43 ` [PATCH 1/5] PCI/IA64: simplify code by " Jiang Liu
2012-08-28 15:43 ` Jiang Liu [this message]
2012-08-28 15:43 ` [PATCH 3/5] PCI/cpcihp: " Jiang Liu
2012-08-28 15:43 ` [PATCH 4/5] PCI/IOV: " Jiang Liu
2012-09-20 20:38   ` Yinghai Lu
2012-09-20 23:59     ` Bjorn Helgaas
2012-09-21  0:02       ` Jiang Liu
2012-09-21  1:51       ` Yinghai Lu
2012-09-21  2:56         ` Bjorn Helgaas
2012-09-21  6:22           ` Yinghai Lu
2012-09-21 14:15             ` Don Dutile
2012-09-21 15:11               ` Yinghai Lu
2012-08-28 15:43 ` [PATCH 5/5] PCI/xen-pcifront: " Jiang Liu
2012-08-28 16:59   ` Konrad Rzeszutek Wilk
2012-08-28 23:56     ` Jiang Liu
2012-09-05 16:29       ` Konrad Rzeszutek Wilk
2012-09-05 20:32   ` Konrad Rzeszutek Wilk
2012-09-17 19:34 ` [PATCH 0/5] Simplify code by using " Bjorn Helgaas

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