On Mon, Sep 27, 2021 at 01:46:31PM +0000, Shameerali Kolothum Thodi wrote: > > > > Nope, this is locked wrong and has no lifetime management. > > > > > > Ok. Holding the device_lock() sufficient here? > > > > You can't hold a hisi_qm pointer with some kind of lifecycle > > management of that pointer. device_lock/etc is necessary to call > > pci_get_drvdata() > > Since this migration driver only supports VF devices and the PF > driver will not be removed until all the VF devices gets removed, > is the locking necessary here? Oh.. That is really busted up. pci_sriov_disable() is called under the device_lock(pf) and obtains the device_lock(vf). This means a VF driver can never use the device_lock(pf), otherwise it can deadlock itself if PF removal triggers VF removal. But you can't access these members without using the device_lock(), as there really are no safety guarentees.. The mlx5 patches have this same sketchy problem. We may need a new special function 'pci_get_sriov_pf_devdata()' that confirms the vf/pf relationship and explicitly interlocks with the pci_sriov_enable/disable instead of using device_lock() Leon, what do you think? Jason
