diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c
index 43a89e4..2cec49d 100644
--- a/drivers/usb/core/hcd.c
+++ b/drivers/usb/core/hcd.c
@@ -1398,11 +1398,10 @@
 					ret = -EAGAIN;
 				else
 					urb->transfer_flags |= URB_DMA_MAP_SG;
-				if (n != urb->num_sgs) {
-					urb->num_sgs = n;
+				urb->num_mapped_sgs = n;
+				if (n != urb->num_sgs)
 					urb->transfer_flags |=
 							URB_DMA_SG_COMBINED;
-				}
 			} else if (urb->sg) {
 				struct scatterlist *sg = urb->sg;
 				urb->transfer_dma = dma_map_page(
diff --git a/drivers/usb/host/ehci-q.c b/drivers/usb/host/ehci-q.c
index f136f7f1..36ca507 100644
--- a/drivers/usb/host/ehci-q.c
+++ b/drivers/usb/host/ehci-q.c
@@ -658,7 +658,7 @@
 	/*
 	 * data transfer stage:  buffer setup
 	 */
-	i = urb->num_sgs;
+	i = urb->num_mapped_sgs;
 	if (len > 0 && i > 0) {
 		sg = urb->sg;
 		buf = sg_dma_address(sg);
diff --git a/drivers/usb/host/uhci-q.c b/drivers/usb/host/uhci-q.c
index f6ca80e..d2c6f5a 100644
--- a/drivers/usb/host/uhci-q.c
+++ b/drivers/usb/host/uhci-q.c
@@ -943,7 +943,7 @@
 	if (usb_pipein(urb->pipe))
 		status |= TD_CTRL_SPD;
 
-	i = urb->num_sgs;
+	i = urb->num_mapped_sgs;
 	if (len > 0 && i > 0) {
 		sg = urb->sg;
 		data = sg_dma_address(sg);
diff --git a/drivers/usb/host/whci/qset.c b/drivers/usb/host/whci/qset.c
index d6e1754..a91712c 100644
--- a/drivers/usb/host/whci/qset.c
+++ b/drivers/usb/host/whci/qset.c
@@ -443,7 +443,7 @@
 
 	remaining = urb->transfer_buffer_length;
 
-	for_each_sg(urb->sg, sg, urb->num_sgs, i) {
+	for_each_sg(urb->sg, sg, urb->num_mapped_sgs, i) {
 		dma_addr_t dma_addr;
 		size_t dma_remaining;
 		dma_addr_t sp, ep;
@@ -561,7 +561,7 @@
 
 	remaining = urb->transfer_buffer_length;
 
-	for_each_sg(urb->sg, sg, urb->num_sgs, i) {
+	for_each_sg(urb->sg, sg, urb->num_mapped_sgs, i) {
 		size_t len;
 		size_t sg_remaining;
 		void *orig;
diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index 133ce30..d030f0b 100644
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -2551,7 +2551,7 @@
 	struct scatterlist *sg;
 
 	sg = NULL;
-	num_sgs = urb->num_sgs;
+	num_sgs = urb->num_mapped_sgs;
 	temp = urb->transfer_buffer_length;
 
 	xhci_dbg(xhci, "count sg list trbs: \n");
@@ -2735,7 +2735,7 @@
 		return -EINVAL;
 
 	num_trbs = count_sg_trbs_needed(xhci, urb);
-	num_sgs = urb->num_sgs;
+	num_sgs = urb->num_mapped_sgs;
 	total_packet_count = roundup(urb->transfer_buffer_length,
 			usb_endpoint_maxp(&urb->ep->desc));
 
diff --git a/include/linux/usb.h b/include/linux/usb.h
index 2f05a7f..4269c3f 100644
--- a/include/linux/usb.h
+++ b/include/linux/usb.h
@@ -1221,6 +1221,7 @@
 	void *transfer_buffer;		/* (in) associated data buffer */
 	dma_addr_t transfer_dma;	/* (in) dma addr for transfer_buffer */
 	struct scatterlist *sg;		/* (in) scatter gather buffer list */
+	int num_mapped_sgs;		/* (internal) mapped sg entries */
 	int num_sgs;			/* (in) number of entries in the sg list */
 	u32 transfer_buffer_length;	/* (in) data buffer length */
 	u32 actual_length;		/* (return) actual transfer length */