[PATCH] USB: shuttle_usbat: Fix handling of scatter-gather buffers

I've worked out what's going wrong. The scsi layer is now much
more likely to pass down scatterlists instead of plain buffers. So
you have to make sure that they're handled correctly. In one of the
changes along the way, usbat_write_block and friends stopped obeying
the srb->use_sg flag.

Anyway, with the appended patch, and the one I'm putting in the next email, it
all seems to work for the HP cd4e. Of course, someone's going to have
to test it with the flash drives as well....

This patch teaches the usbat_{read,write}_block functions to
obey the use_sg flag in the scsi-request.

Signed-off-by: Peter Chubb <[e-mail]>
Signed-off-by: Daniel Drake <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/usb/storage/shuttle_usbat.c

···
  * Convenience function to perform a bulk read
  */
 static int usbat_bulk_read(struct us_data *us,
-							 unsigned char *data,
-							 unsigned int len)
+			   unsigned char *data,
+			   unsigned int len,
+			   int use_sg)
 {
 	if (len == 0)
 		return USB_STOR_XFER_GOOD;
 
 	US_DEBUGP("usbat_bulk_read: len = %d\n", len);
-	return usb_stor_bulk_transfer_buf(us, us->recv_bulk_pipe, data, len, NULL);
+	return usb_stor_bulk_transfer_sg(us, us->recv_bulk_pipe, data, len, use_sg, NULL);
 }
 
 /*
  * Convenience function to perform a bulk write
  */
 static int usbat_bulk_write(struct us_data *us,
-							unsigned char *data,
-							unsigned int len)
+			    unsigned char *data,
+			    unsigned int len,
+			    int use_sg)
 {
 	if (len == 0)
 		return USB_STOR_XFER_GOOD;
 
 	US_DEBUGP("usbat_bulk_write:  len = %d\n", len);
-	return usb_stor_bulk_transfer_buf(us, us->send_bulk_pipe, data, len, NULL);
+	return usb_stor_bulk_transfer_sg(us, us->send_bulk_pipe, data, len, use_sg, NULL);
 }
 
 /*
···
  */
 static int usbat_read_block(struct us_data *us,
 			    unsigned char *content,
-			    unsigned short len)
+			    unsigned short len,
+			    int use_sg)
 {
 	int result;
 	unsigned char *command = us->iobuf;
···
 	if (result != USB_STOR_XFER_GOOD)
 		return USB_STOR_TRANSPORT_ERROR;
 
-	result = usbat_bulk_read(us, content, len);
+	result = usbat_bulk_read(us, content, len, use_sg);
 	return (result == USB_STOR_XFER_GOOD ?
 			USB_STOR_TRANSPORT_GOOD : USB_STOR_TRANSPORT_ERROR);
 }
···
 			     unsigned char access,
 			     unsigned char *content,
 			     unsigned short len,
-			     int minutes)
+			     int minutes,
+			     int use_sg)
 {
 	int result;
 	unsigned char *command = us->iobuf;
···
 	if (result != USB_STOR_XFER_GOOD)
 		return USB_STOR_TRANSPORT_ERROR;
 
-	result = usbat_bulk_write(us, content, len);
+	result = usbat_bulk_write(us, content, len, use_sg);
 	if (result != USB_STOR_XFER_GOOD)
 		return USB_STOR_TRANSPORT_ERROR;
 
···
 				data[1+(j<<1)] = data_out[j];
 			}
 
-			result = usbat_bulk_write(us, data, num_registers*2);
+			result = usbat_bulk_write(us, data, num_registers*2, 0);
 			if (result != USB_STOR_XFER_GOOD)
 				return USB_STOR_TRANSPORT_ERROR;
 
···
 	}
 
 	/* Send the data */
-	result = usbat_bulk_write(us, data, num_registers*2);
+	result = usbat_bulk_write(us, data, num_registers*2, 0);
 	if (result != USB_STOR_XFER_GOOD)
 		return USB_STOR_TRANSPORT_ERROR;
 
···
  * other related details) are defined beforehand with _set_shuttle_features().
  */
 static int usbat_read_blocks(struct us_data *us,
-							 unsigned char *buffer,
-							 int len)
+			     unsigned char *buffer,
+			     int len,
+			     int use_sg)
 {
 	int result;
 	unsigned char *command = us->iobuf;
···
 		return USB_STOR_TRANSPORT_FAILED;
 	
 	/* Read the blocks we just asked for */
-	result = usbat_bulk_read(us, buffer, len);
+	result = usbat_bulk_read(us, buffer, len, use_sg);
 	if (result != USB_STOR_XFER_GOOD)
 		return USB_STOR_TRANSPORT_FAILED;
 
···
  */
 static int usbat_write_blocks(struct us_data *us,
 							  unsigned char *buffer,
-							  int len)
+			      int len,
+			      int use_sg)
 {
 	int result;
 	unsigned char *command = us->iobuf;
···
 		return USB_STOR_TRANSPORT_FAILED;
 	
 	/* Write the data */
-	result = usbat_bulk_write(us, buffer, len);
+	result = usbat_bulk_write(us, buffer, len, use_sg);
 	if (result != USB_STOR_XFER_GOOD)
 		return USB_STOR_TRANSPORT_FAILED;
 
···
 	msleep(100);
 
 	/* Read the device identification data */
-	rc = usbat_read_block(us, reply, 512);
+	rc = usbat_read_block(us, reply, 512, 0);
 	if (rc != USB_STOR_TRANSPORT_GOOD)
 		goto leave;
 
···
 			goto leave;
 
 		/* Read the data we just requested */
-		result = usbat_read_blocks(us, buffer, len);
+		result = usbat_read_blocks(us, buffer, len, 0);
 		if (result != USB_STOR_TRANSPORT_GOOD)
 			goto leave;
   	 
···
 			goto leave;
 
 		/* Write the data */
-		result = usbat_write_blocks(us, buffer, len);
+		result = usbat_write_blocks(us, buffer, len, 0);
 		if (result != USB_STOR_TRANSPORT_GOOD)
 			goto leave;
 
···
 	 * AT SPEED 4 IS UNRELIABLE!!!
 	 */
 
-	if ( (result = usbat_write_block(us, 
+	if ((result = usbat_write_block(us,
 			USBAT_ATA, srb->cmnd, 12,
-			srb->cmnd[0]==GPCMD_BLANK ? 75 : 10)) !=
-				USB_STOR_TRANSPORT_GOOD) {
+				(srb->cmnd[0]==GPCMD_BLANK ? 75 : 10), 0) !=
+			     USB_STOR_TRANSPORT_GOOD)) {
 		return result;
 	}
 
···
 			len = *status;
 
 
-		result = usbat_read_block(us, srb->request_buffer, len);
+		result = usbat_read_block(us, srb->request_buffer, len, srb->use_sg);
 
 		/* Debug-print the first 32 bytes of the transfer */