On Thu, Aug 05 2021, Jason Gunthorpe <jgg@xxxxxxxxxx> wrote: > vfio_pci_try_bus_reset() is triggering a reset of the entire_dev set if > any device within it has accumulated a needs_reset. This reset can only be > done once all of the drivers operating the PCI devices to be reset are in > a known safe state. > > Make this clearer by directly operating on the dev_set instead of the > vfio_pci_device. Rename the function to vfio_pci_dev_set_try_reset(). > > Use the device list inside the dev_set to check that all drivers are in a > safe state instead of working backwards from the pci_device. > > The dev_set->lock directly prevents devices from joining/leaving the set, > or changing their state, which further implies the pci_device cannot > change drivers or that the vfio_device be freed, eliminating the need for > get/put's. > > If a pci_device to be reset is not in the dev_set then the reset cannot be > used as we can't know what the state of that driver is. Directly measure > this by checking that every pci_device is in the dev_set - which > effectively proves that VFIO drivers are attached to everything. > > Remove the odd interaction around vfio_pci_set_power_state() - have the > only caller avoid its redundant vfio_pci_set_power_state() instead of > avoiding it inside vfio_pci_dev_set_try_reset(). > > This restructuring corrects a call to pci_dev_driver() without holding the > device_lock() and removes a hard wiring to &vfio_pci_driver. > > Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxx> > --- > drivers/vfio/pci/vfio_pci.c | 182 +++++++++++++++++------------------- > 1 file changed, 86 insertions(+), 96 deletions(-) Reviewed-by: Cornelia Huck <cohuck@xxxxxxxxxx>
