On Wed, Jan 23, 2019 at 05:30:49PM +0100, Joerg Roedel wrote: > + max_size = virtio_max_dma_size(vdev); > + > /* Host can optionally specify maximum segment size and number of > * segments. */ > err = virtio_cread_feature(vdev, VIRTIO_BLK_F_SIZE_MAX, > struct virtio_blk_config, size_max, &v); > if (!err) > - blk_queue_max_segment_size(q, v); > - else > - blk_queue_max_segment_size(q, -1U); > + max_size = min(max_size, v); > + > + blk_queue_max_segment_size(q, max_size); I wonder if we should just move the dma max segment size check into blk_queue_max_segment_size so that all block drivers benefit from it. Even if not I think at least the SCSI midlayer should be updated to support it. Btw, I wonder why virtio-scsi sticks to the default segment size, unlike virtio-blk.
