On Wed, Jan 23, 2019 at 10:31:39PM +0100, Christoph Hellwig wrote: > 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. In that case the limit would also apply to virtio-blk even if it doesn't use the DMA-API. If that is acceptable we can move the check to blk_queue_max_segment_size(). Regards, Joerg
