block-backend: align max_transfer to request alignment
Block device requests must be aligned to bs->bl.request_alignment.
It makes sense for drivers to align bs->bl.max_transfer the same
way; however when there is no specified limit, blk_get_max_transfer
just returns INT_MAX. Since the contract of the function does not
specify that INT_MAX means "no maximum", just align the outcome
of the function (whether INT_MAX or bs->bl.max_transfer) before
returning it.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/block/block-backend.c b/block/block-backend.c
index 15f1ea4..6e37582 100644
--- a/block/block-backend.c
+++ b/block/block-backend.c
@@ -1957,12 +1957,12 @@
uint32_t blk_get_max_transfer(BlockBackend *blk)
{
BlockDriverState *bs = blk_bs(blk);
- uint32_t max = 0;
+ uint32_t max = INT_MAX;
if (bs) {
- max = bs->bl.max_transfer;
+ max = MIN_NON_ZERO(max, bs->bl.max_transfer);
}
- return MIN_NON_ZERO(max, INT_MAX);
+ return ROUND_DOWN(max, blk_get_request_alignment(blk));
}
int blk_get_max_iov(BlockBackend *blk)
