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authorKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>2014-12-03 22:40:26 +0100
committerDavid Vrabel <david.vrabel@citrix.com>2014-12-04 13:41:58 +0100
commite8801a7418dda995a70f30874aef77e6d064828e (patch)
treeee4e691009b468c5397216b9e5776c6c239cc51e /drivers/xen/xen-pciback/pciback.h
parentswiotlb-xen: pass dev_addr to swiotlb_tbl_unmap_single (diff)
downloadlinux-e8801a7418dda995a70f30874aef77e6d064828e.tar.xz
linux-e8801a7418dda995a70f30874aef77e6d064828e.zip
xen/pciback: Don't deadlock when unbinding.
As commit 0a9fd0152929db372ff61b0d6c280fdd34ae8bdb 'xen/pciback: Document the entry points for 'pcistub_put_pci_dev'' explained there are four entry points in this function. Two of them are when the user fiddles in the SysFS to unbind a device which might be in use by a guest or not. Both 'unbind' states will cause a deadlock as the the PCI lock has already been taken, which then pci_device_reset tries to take. We can simplify this by requiring that all callers of pcistub_put_pci_dev MUST hold the device lock. And then we can just call the lockless version of pci_device_reset. To make it even simpler we will modify xen_pcibk_release_pci_dev to quality whether it should take a lock or not - as it ends up calling xen_pcibk_release_pci_dev and needs to hold the lock. Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Diffstat (limited to 'drivers/xen/xen-pciback/pciback.h')
-rw-r--r--drivers/xen/xen-pciback/pciback.h7
1 files changed, 4 insertions, 3 deletions
diff --git a/drivers/xen/xen-pciback/pciback.h b/drivers/xen/xen-pciback/pciback.h
index f72af87640e0..58e38d586f52 100644
--- a/drivers/xen/xen-pciback/pciback.h
+++ b/drivers/xen/xen-pciback/pciback.h
@@ -99,7 +99,8 @@ struct xen_pcibk_backend {
unsigned int *domain, unsigned int *bus,
unsigned int *devfn);
int (*publish)(struct xen_pcibk_device *pdev, publish_pci_root_cb cb);
- void (*release)(struct xen_pcibk_device *pdev, struct pci_dev *dev);
+ void (*release)(struct xen_pcibk_device *pdev, struct pci_dev *dev,
+ bool lock);
int (*add)(struct xen_pcibk_device *pdev, struct pci_dev *dev,
int devid, publish_pci_dev_cb publish_cb);
struct pci_dev *(*get)(struct xen_pcibk_device *pdev,
@@ -122,10 +123,10 @@ static inline int xen_pcibk_add_pci_dev(struct xen_pcibk_device *pdev,
}
static inline void xen_pcibk_release_pci_dev(struct xen_pcibk_device *pdev,
- struct pci_dev *dev)
+ struct pci_dev *dev, bool lock)
{
if (xen_pcibk_backend && xen_pcibk_backend->release)
- return xen_pcibk_backend->release(pdev, dev);
+ return xen_pcibk_backend->release(pdev, dev, lock);
}
static inline struct pci_dev *