usb-storage: use hcd_uses_dma to check for DMA capabilities

The dma_mask on its own doesn't mean much.  Instead check for the actual
flag.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20190903084615.19161-4-hch@lst.deSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/storage/scsiglue.c

@@ -40,6 +40,7 @@
 #include <scsi/scsi_eh.h>
 
 #include "usb.h"
+#include <linux/usb/hcd.h>
 #include "scsiglue.h"
 #include "debug.h"
 #include "transport.h"
@@ -141,11 +142,10 @@ static int slave_configure(struct scsi_device *sdev)
 
 	/*
 	 * Some USB host controllers can't do DMA; they have to use PIO.
-	 * They indicate this by setting their dma_mask to NULL.  For
-	 * such controllers we need to make sure the block layer sets
+	 * For such controllers we need to make sure the block layer sets
 	 * up bounce buffers in addressable memory.
 	 */
-	if (!us->pusb_dev->bus->controller->dma_mask)
+	if (!hcd_uses_dma(bus_to_hcd(us->pusb_dev->bus)))
 		blk_queue_bounce_limit(sdev->request_queue, BLK_BOUNCE_HIGH);
 
 	/*