4.0-stable review patch. If anyone has any objections, please let me know.
------------------ From: Alex Williamson <[email protected]> commit db7d4d7f40215843000cb9d441c9149fd42ea36b upstream. Commit 13060b64b819 ("vfio: Add and use device request op for vfio bus drivers") incorrectly makes use of an interruptible timeout. When interrupted, the signal remains pending resulting in subsequent timeouts occurring instantly. This makes the loop spin at a much higher rate than intended. Instead of making this completely non-interruptible, we can change this into a sort of interruptible-once behavior and use the "once" to log debug information. The driver API doesn't allow us to abort and return an error code. Signed-off-by: Alex Williamson <[email protected]> Fixes: 13060b64b819 Signed-off-by: Greg Kroah-Hartman <[email protected]> --- drivers/vfio/vfio.c | 21 ++++++++++++++++++--- 1 file changed, 18 insertions(+), 3 deletions(-) --- a/drivers/vfio/vfio.c +++ b/drivers/vfio/vfio.c @@ -711,6 +711,8 @@ void *vfio_del_group_dev(struct device * void *device_data = device->device_data; struct vfio_unbound_dev *unbound; unsigned int i = 0; + long ret; + bool interrupted = false; /* * The group exists so long as we have a device reference. Get @@ -756,9 +758,22 @@ void *vfio_del_group_dev(struct device * vfio_device_put(device); - } while (wait_event_interruptible_timeout(vfio.release_q, - !vfio_dev_present(group, dev), - HZ * 10) <= 0); + if (interrupted) { + ret = wait_event_timeout(vfio.release_q, + !vfio_dev_present(group, dev), HZ * 10); + } else { + ret = wait_event_interruptible_timeout(vfio.release_q, + !vfio_dev_present(group, dev), HZ * 10); + if (ret == -ERESTARTSYS) { + interrupted = true; + dev_warn(dev, + "Device is currently in use, task" + " \"%s\" (%d) " + "blocked until device is released", + current->comm, task_pid_nr(current)); + } + } + } while (ret <= 0); vfio_group_put(group); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
