• Konrad Rzeszutek Wilk's avatar
    xen/pciback: Don't deadlock when unbinding. · e8801a74
    Konrad Rzeszutek Wilk authored
    As commit 0a9fd015
    '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: default avatarBoris Ostrovsky <boris.ostrovsky@oracle.com>
    Signed-off-by: default avatarKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
    Signed-off-by: default avatarDavid Vrabel <david.vrabel@citrix.com>
    e8801a74
passthrough.c 4.74 KB