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

From: Joerg Roedel
Date: Tue Jan 29 2019 - 03:44:05 EST


From: Joerg Roedel <jroedel@xxxxxxx>

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.wilk@xxxxxxxxxx>
Signed-off-by: Joerg Roedel <jroedel@xxxxxxx>
---
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