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[RFC,6/6] VFIO: use ACCESS_ONCE() to guard access to dev->driver

Message ID 1352555839-18961-6-git-send-email-jiang.liu@huawei.com (mailing list archive)
State New, archived
Headers show

Commit Message

Jiang Liu Nov. 10, 2012, 1:57 p.m. UTC 
From: Jiang Liu <jiang.liu@huawei.com>

Comments from dev_driver_string(),
/* dev->driver can change to NULL underneath us because of unbinding,
 * so be careful about accessing it.
 */

So use ACCESS_ONCE() to guard access to dev->driver field.

Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
---
 drivers/vfio/vfio.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
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Patch

diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c
index 18714b9..f158e42 100644
--- a/drivers/vfio/vfio.c
+++ b/drivers/vfio/vfio.c
@@ -520,8 +520,9 @@  static bool vfio_whitelisted_driver(struct device_driver *drv)
 static int vfio_dev_viable(struct device *dev, void *data)
 {
 	struct vfio_device_driver *driver;
+	struct device_driver *drv = ACCESS_ONCE(dev->driver);
 
-	if (!dev->driver || vfio_whitelisted_driver(dev->driver))
+	if (!drv || vfio_whitelisted_driver(drv))
 		return 0;
 
 	mutex_lock(&vfio.device_drivers_lock);