Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost

Pull virtio updates from Michael Tsirkin:
 "A small number of improvements all over the place:

   - shutdown has been reworked to reset devices

   - virtio fs is now allowed in vduse

   - vhost-scsi memory use has been reduced

   - cleanups, fixes all over the place

  A couple more fixes are being tested and will be merged after rc1"

* tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost:
  vhost-scsi: Reduce response iov mem use
  vhost-scsi: Allocate iov_iter used for unaligned copies when needed
  vhost-scsi: Stop duplicating se_cmd fields
  vhost-scsi: Dynamically allocate scatterlists
  vhost-scsi: Return queue full for page alloc failures during copy
  vhost-scsi: Add better resource allocation failure handling
  vhost-scsi: Allocate T10 PI structs only when enabled
  vhost-scsi: Reduce mem use by moving upages to per queue
  vduse: add virtio_fs to allowed dev id
  sound/virtio: Fix cancel_sync warnings on uninitialized work_structs
  vdpa/mlx5: Fix oversized null mkey longer than 32bit
  vdpa/mlx5: Fix mlx5_vdpa_get_config() endianness on big-endian machines
  vhost-scsi: Fix handling of multiple calls to vhost_scsi_set_endpoint
  tools: virtio/linux/module.h add MODULE_DESCRIPTION() define.
  tools: virtio/linux/compiler.h: Add data_race() define.
  tools/virtio: Add DMA_MAPPING_ERROR and sg_dma_len api define for virtio test
  virtio: break and reset virtio devices on device_shutdown()

1 files changed, 29 insertions, 0 deletions

diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c
index ba37665188b5..150753c3b578 100644
--- a/drivers/virtio/virtio.c
+++ b/drivers/virtio/virtio.c
@@ -395,6 +395,34 @@ static const struct cpumask *virtio_irq_get_affinity(struct device *_d,
 	return dev->config->get_vq_affinity(dev, irq_vec);
 }
 
+static void virtio_dev_shutdown(struct device *_d)
+{
+	struct virtio_device *dev = dev_to_virtio(_d);
+	struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
+
+	/*
+	 * Stop accesses to or from the device.
+	 * We only need to do it if there's a driver - no accesses otherwise.
+	 */
+	if (!drv)
+		return;
+
+	/*
+	 * Some devices get wedged if you kick them after they are
+	 * reset. Mark all vqs as broken to make sure we don't.
+	 */
+	virtio_break_device(dev);
+	/*
+	 * Guarantee that any callback will see vq->broken as true.
+	 */
+	virtio_synchronize_cbs(dev);
+	/*
+	 * As IOMMUs are reset on shutdown, this will block device access to memory.
+	 * Some devices get wedged if this happens, so reset to make sure it does not.
+	 */
+	dev->config->reset(dev);
+}
+
 static const struct bus_type virtio_bus = {
 	.name  = "virtio",
 	.match = virtio_dev_match,
@@ -403,6 +431,7 @@ static const struct bus_type virtio_bus = {
 	.probe = virtio_dev_probe,
 	.remove = virtio_dev_remove,
 	.irq_get_affinity = virtio_irq_get_affinity,
+	.shutdown = virtio_dev_shutdown,
 };
 
 int __register_virtio_driver(struct virtio_driver *driver, struct module *owner)