USB: Change the scatterlist type in struct urb

Change the type of the URB's 'sg' pointer from a usb_sg_request to
a scatterlist.  This allows drivers to submit scatter-gather lists
without using the usb_sg_wait() interface.  It has the added benefit
of removing the typecasts that were added as part of patch as1368 (and
slightly decreasing the number of pointer dereferences).
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Reviewed-by: Alan Stern <stern@rowland.harvard.edu>
Tested-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/core/hcd.c

@@ -1278,7 +1278,7 @@ static void unmap_urb_for_dma(struct usb_hcd *hcd, struct urb *urb)
 	dir = usb_urb_dir_in(urb) ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
 	if (urb->transfer_flags & URB_DMA_MAP_SG)
 		dma_unmap_sg(hcd->self.controller,
-				urb->sg->sg,
+				urb->sg,
 				urb->num_sgs,
 				dir);
 	else if (urb->transfer_flags & URB_DMA_MAP_PAGE)
@@ -1346,7 +1346,7 @@ static int map_urb_for_dma(struct usb_hcd *hcd, struct urb *urb,
 			if (urb->num_sgs) {
 				int n = dma_map_sg(
 						hcd->self.controller,
-						urb->sg->sg,
+						urb->sg,
 						urb->num_sgs,
 						dir);
 				if (n <= 0)
@@ -1359,9 +1359,7 @@ static int map_urb_for_dma(struct usb_hcd *hcd, struct urb *urb,
 							URB_DMA_SG_COMBINED;
 				}
 			} else if (urb->sg) {
-				struct scatterlist *sg;
-
-				sg = (struct scatterlist *) urb->sg;
+				struct scatterlist *sg = urb->sg;
 				urb->transfer_dma = dma_map_page(
 						hcd->self.controller,
 						sg_page(sg),

drivers/usb/core/message.c

@@ -413,7 +413,7 @@ int usb_sg_init(struct usb_sg_request *io, struct usb_device *dev,
 					sg->length;
 			}
 		}
-		io->urbs[0]->sg = io;
+		io->urbs[0]->sg = sg;
 		io->urbs[0]->num_sgs = io->entries;
 		io->entries = 1;
 	} else {
@@ -454,7 +454,7 @@ int usb_sg_init(struct usb_sg_request *io, struct usb_device *dev,
 			}
 			io->urbs[i]->transfer_buffer_length = len;
 
-			io->urbs[i]->sg = (struct usb_sg_request *) sg;
+			io->urbs[i]->sg = sg;
 		}
 		io->urbs[--i]->transfer_flags &= ~URB_NO_INTERRUPT;
 	}

drivers/usb/host/ehci-q.c

@@ -663,7 +663,7 @@ qh_urb_transaction (
 	 */
 	i = urb->num_sgs;
 	if (len > 0 && i > 0) {
-		sg = urb->sg->sg;
+		sg = urb->sg;
 		buf = sg_dma_address(sg);
 
 		/* urb->transfer_buffer_length may be smaller than the

drivers/usb/host/whci/qset.c

@@ -443,7 +443,7 @@ static int qset_add_urb_sg(struct whc *whc, struct whc_qset *qset, struct urb *u
 
 	remaining = urb->transfer_buffer_length;
 
-	for_each_sg(urb->sg->sg, sg, urb->num_sgs, i) {
+	for_each_sg(urb->sg, sg, urb->num_sgs, i) {
 		dma_addr_t dma_addr;
 		size_t dma_remaining;
 		dma_addr_t sp, ep;
@@ -561,7 +561,7 @@ static int qset_add_urb_sg_linearize(struct whc *whc, struct whc_qset *qset,
 
 	remaining = urb->transfer_buffer_length;
 
-	for_each_sg(urb->sg->sg, sg, urb->sg->nents, i) {
+	for_each_sg(urb->sg, sg, urb->num_sgs, i) {
 		size_t len;
 		size_t sg_remaining;
 		void *orig;

drivers/usb/host/xhci-ring.c

@@ -1788,7 +1788,7 @@ static unsigned int count_sg_trbs_needed(struct xhci_hcd *xhci, struct urb *urb)
 
 	xhci_dbg(xhci, "count sg list trbs: \n");
 	num_trbs = 0;
-	for_each_sg(urb->sg->sg, sg, num_sgs, i) {
+	for_each_sg(urb->sg, sg, num_sgs, i) {
 		unsigned int previous_total_trbs = num_trbs;
 		unsigned int len = sg_dma_len(sg);
 
@@ -1951,7 +1951,7 @@ static int queue_bulk_sg_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
 	 *    the amount of memory allocated for this scatter-gather list.
 	 * 3. TRBs buffers can't cross 64KB boundaries.
 	 */
-	sg = urb->sg->sg;
+	sg = urb->sg;
 	addr = (u64) sg_dma_address(sg);
 	this_sg_len = sg_dma_len(sg);
 	trb_buff_len = TRB_MAX_BUFF_SIZE -

drivers/usb/mon/mon_bin.c

@@ -422,7 +422,7 @@ static unsigned int mon_bin_get_data(const struct mon_reader_bin *rp,
 		}
 
 		/* Copy up to the first non-addressable segment */
-		for_each_sg(urb->sg->sg, sg, urb->num_sgs, i) {
+		for_each_sg(urb->sg, sg, urb->num_sgs, i) {
 			if (length == 0 || PageHighMem(sg_page(sg)))
 				break;
 			this_len = min_t(unsigned int, sg->length, length);

drivers/usb/mon/mon_text.c

@@ -159,7 +159,7 @@ static inline char mon_text_get_data(struct mon_event_text *ep, struct urb *urb,
 		if (src == NULL)
 			return 'Z';	/* '0' would be not as pretty. */
 	} else {
-		struct scatterlist *sg = urb->sg->sg;
+		struct scatterlist *sg = urb->sg;
 
 		if (PageHighMem(sg_page(sg)))
 			return 'D';

include/linux/usb.h

@@ -1195,7 +1195,7 @@ struct urb {
 	unsigned int transfer_flags;	/* (in) URB_SHORT_NOT_OK | ...*/
 	void *transfer_buffer;		/* (in) associated data buffer */
 	dma_addr_t transfer_dma;	/* (in) dma addr for transfer_buffer */
-	struct usb_sg_request *sg;	/* (in) scatter gather buffer list */
+	struct scatterlist *sg;		/* (in) scatter gather buffer list */
 	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 */