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

Commit Message

Joerg Roedel Jan. 29, 2019, 8:43 a.m. UTC

From: Joerg Roedel <[e-mail]>

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 <[e-mail]>
Signed-off-by: Joerg Roedel <[e-mail]>
---
 drivers/block/virtio_blk.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

Comments

Christoph Hellwig Jan. 29, 2019, 5:13 p.m. UTC | #1

On Tue, Jan 29, 2019 at 09:43:42AM +0100, Joerg Roedel wrote:
> From: Joerg Roedel <[e-mail]>
> 
> 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 <[e-mail]>
> Signed-off-by: Joerg Roedel <[e-mail]>

Looks good:

Reviewed-by: Christoph Hellwig <[e-mail]>

Patch

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,