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

Pull virtio updates from Michael Tsirkin:
 "Several fixes, most notably fix for virtio on swiotlb systems"

* tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost:
  vhost: silence an unused-variable warning
  virtio: hint if callbacks surprisingly might sleep
  virtio-ccw: wire up ->bus_name callback
  s390/virtio: handle find on invalid queue gracefully
  virtio-ccw: diag 500 may return a negative cookie
  virtio_balloon: remove the unnecessary 0-initialization
  virtio-balloon: improve update_balloon_size_func
  virtio-blk: Consider virtio_max_dma_size() for maximum segment size
  virtio: Introduce virtio_max_dma_size()
  dma: Introduce dma_max_mapping_size()
  swiotlb: Add is_swiotlb_active() function
  swiotlb: Introduce swiotlb_max_mapping_size()

1 files changed, 14 insertions, 0 deletions

diff --git a/kernel/dma/mapping.c b/kernel/dma/mapping.c
index ef2aba503467..c000906348c9 100644
--- a/kernel/dma/mapping.c
+++ b/kernel/dma/mapping.c
@@ -360,3 +360,17 @@ void dma_cache_sync(struct device *dev, void *vaddr, size_t size,
 		ops->cache_sync(dev, vaddr, size, dir);
 }
 EXPORT_SYMBOL(dma_cache_sync);
+
+size_t dma_max_mapping_size(struct device *dev)
+{
+	const struct dma_map_ops *ops = get_dma_ops(dev);
+	size_t size = SIZE_MAX;
+
+	if (dma_is_direct(ops))
+		size = dma_direct_max_mapping_size(dev);
+	else if (ops && ops->max_mapping_size)
+		size = ops->max_mapping_size(dev);
+
+	return size;
+}
+EXPORT_SYMBOL_GPL(dma_max_mapping_size);