BlockLimits: introduce max_transfer_length

Signed-off-by: Peter Lieven <pl@kamp.de>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/block.c b/block.c
index 88f6d9b236..76fcc1d6d3 100644
--- a/block.c
+++ b/block.c
@@ -519,6 +519,7 @@ void bdrv_refresh_limits(BlockDriverState *bs, Error **errp)
             return;
         }
         bs->bl.opt_transfer_length = bs->file->bl.opt_transfer_length;
+        bs->bl.max_transfer_length = bs->file->bl.max_transfer_length;
         bs->bl.opt_mem_alignment = bs->file->bl.opt_mem_alignment;
     } else {
         bs->bl.opt_mem_alignment = 512;
@@ -533,6 +534,9 @@ void bdrv_refresh_limits(BlockDriverState *bs, Error **errp)
         bs->bl.opt_transfer_length =
             MAX(bs->bl.opt_transfer_length,
                 bs->backing_hd->bl.opt_transfer_length);
+        bs->bl.max_transfer_length =
+            MIN_NON_ZERO(bs->bl.max_transfer_length,
+                         bs->backing_hd->bl.max_transfer_length);
         bs->bl.opt_mem_alignment =
             MAX(bs->bl.opt_mem_alignment,
                 bs->backing_hd->bl.opt_mem_alignment);