This patch adds a helper function whether a queue can merge
the segments by the DMA MAP layer (e.g. via IOMMU).
Signed-off-by: NYoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: Simon Horman <horms+renesas@verge.net.au
Signed-off-by: NChristoph Hellwig <hch@lst.de>