[media] dib0700: be sure that dib0700_ctrl_rd() users can do DMA

dib0700_ctrl_rd() takes a RX and a TX pointer. Be sure that
both will point to a memory allocated via kmalloc().
Reviewed-by: Patrick Boettcher <patrick.boettcher@posteo.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

drivers/media/usb/dvb-usb/dib0700_core.c

@@ -292,13 +292,15 @@ static int dib0700_i2c_xfer_legacy(struct i2c_adapter *adap,
 
 			/* special thing in the current firmware: when length is zero the read-failed */
 			len = dib0700_ctrl_rd(d, st->buf, msg[i].len + 2,
-					msg[i+1].buf, msg[i+1].len);
+					      st->buf, msg[i + 1].len);
 			if (len <= 0) {
 				deb_info("I2C read failed on address 0x%02x\n",
 						msg[i].addr);
 				break;
 			}
 
+			memcpy(msg[i + 1].buf, st->buf, msg[i + 1].len);
+
 			msg[i+1].len = len;
 
 			i++;

drivers/media/usb/dvb-usb/dib0700_devices.c

@@ -508,8 +508,6 @@ static int stk7700ph_tuner_attach(struct dvb_usb_adapter *adap)
 
 #define DEFAULT_RC_INTERVAL 50
 
-static u8 rc_request[] = { REQUEST_POLL_RC, 0 };
-
 /*
  * This function is used only when firmware is < 1.20 version. Newer
  * firmwares use bulk mode, with functions implemented at dib0700_core,
@@ -517,7 +515,6 @@ static u8 rc_request[] = { REQUEST_POLL_RC, 0 };
  */
 static int dib0700_rc_query_old_firmware(struct dvb_usb_device *d)
 {
-	u8 key[4];
 	enum rc_type protocol;
 	u32 scancode;
 	u8 toggle;
@@ -532,39 +529,43 @@ static int dib0700_rc_query_old_firmware(struct dvb_usb_device *d)
 		return 0;
 	}
 
-	i = dib0700_ctrl_rd(d, rc_request, 2, key, 4);
+	st->buf[0] = REQUEST_POLL_RC;
+	st->buf[1] = 0;
+
+	i = dib0700_ctrl_rd(d, st->buf, 2, st->buf, 4);
 	if (i <= 0) {
 		err("RC Query Failed");
-		return -1;
+		return -EIO;
 	}
 
 	/* losing half of KEY_0 events from Philipps rc5 remotes.. */
-	if (key[0] == 0 && key[1] == 0 && key[2] == 0 && key[3] == 0)
+	if (st->buf[0] == 0 && st->buf[1] == 0
+	    && st->buf[2] == 0 && st->buf[3] == 0)
 		return 0;
 
-	/* info("%d: %2X %2X %2X %2X",dvb_usb_dib0700_ir_proto,(int)key[3-2],(int)key[3-3],(int)key[3-1],(int)key[3]);  */
+	/* info("%d: %2X %2X %2X %2X",dvb_usb_dib0700_ir_proto,(int)st->buf[3 - 2],(int)st->buf[3 - 3],(int)st->buf[3 - 1],(int)st->buf[3]);  */
 
 	dib0700_rc_setup(d, NULL); /* reset ir sensor data to prevent false events */
 
 	switch (d->props.rc.core.protocol) {
 	case RC_BIT_NEC:
 		/* NEC protocol sends repeat code as 0 0 0 FF */
-		if ((key[3-2] == 0x00) && (key[3-3] == 0x00) &&
-		    (key[3] == 0xff)) {
+		if ((st->buf[3 - 2] == 0x00) && (st->buf[3 - 3] == 0x00) &&
+		    (st->buf[3] == 0xff)) {
 			rc_repeat(d->rc_dev);
 			return 0;
 		}
 
 		protocol = RC_TYPE_NEC;
-		scancode = RC_SCANCODE_NEC(key[3-2], key[3-3]);
+		scancode = RC_SCANCODE_NEC(st->buf[3 - 2], st->buf[3 - 3]);
 		toggle = 0;
 		break;
 
 	default:
 		/* RC-5 protocol changes toggle bit on new keypress */
 		protocol = RC_TYPE_RC5;
-		scancode = RC_SCANCODE_RC5(key[3-2], key[3-3]);
-		toggle = key[3-1];
+		scancode = RC_SCANCODE_RC5(st->buf[3 - 2], st->buf[3 - 3]);
+		toggle = st->buf[3 - 1];
 		break;
 	}