[PATCH 5/5] virtio-blk: Consider virtio_max_dma_size() for maximum segment size

[Joerg Roedel]

From: Joerg Roedel <jroe...@suse.de>

Segments can't be larger than the maximum DMA mapping size
supported on the platform. Take that into account when
setting the maximum segment size for a block device.

Reviewed-by: Konrad Rzeszutek Wilk <konrad.w...@oracle.com>
Reviewed-by: Christoph Hellwig <h...@lst.de>
Signed-off-by: Joerg Roedel <jroe...@suse.de>
---
 drivers/block/virtio_blk.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
index b16a887bbd02..4bc083b7c9b5 100644
--- a/drivers/block/virtio_blk.c
+++ b/drivers/block/virtio_blk.c
@@ -723,7 +723,7 @@ static int virtblk_probe(struct virtio_device *vdev)
        struct request_queue *q;
        int err, index;
 
-       u32 v, blk_size, sg_elems, opt_io_size;
+       u32 v, blk_size, max_size, sg_elems, opt_io_size;
        u16 min_io_size;
        u8 physical_block_exp, alignment_offset;
 
@@ -826,14 +826,16 @@ static int virtblk_probe(struct virtio_device *vdev)
        /* No real sector limit. */
        blk_queue_max_hw_sectors(q, -1U);
 
+       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);
 
        /* Host can optionally specify the block size of the device */
        err = virtio_cread_feature(vdev, VIRTIO_BLK_F_BLK_SIZE,
-- 
2.17.1