linux-kernel - [PATCH] usb: gadget: mv_udc: clarify a switch with an implicit fall-through

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Date:   Wed,  1 Mar 2017 15:34:19 +0100
From:   Michal Nazarewicz <mina86@...a86.com>
To:     Felipe Balbi <felipe.balbi@...ux.intel.com>
Cc:     linux-kernel@...r.kernel.org, linux-usb@...r.kernel.org,
        Michal Nazarewicz <mina86@...a86.com>
Subject: [PATCH] usb: gadget: mv_udc: clarify a switch with an implicit fall-through

Rearrange statements in mv_ep_enable function so that it’s obvious
what the switch does and how zlt, ios and mult variables are
initialised.  Most notably, this gets rid of an implicit fall-through
so people don’t have to wonder whether it was intenional or not.

Addresses-Coverity-ID: 201385
Reported-by: Gustavo A. R. Silva <garsilva@...eddedor.com>
Signed-off-by: Michal Nazarewicz <mina86@...a86.com>
---
 drivers/usb/gadget/udc/mv_udc_core.c | 13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/drivers/usb/gadget/udc/mv_udc_core.c b/drivers/usb/gadget/udc/mv_udc_core.c
index 27ebb0d5449d..76f56c5762f9 100644
--- a/drivers/usb/gadget/udc/mv_udc_core.c
+++ b/drivers/usb/gadget/udc/mv_udc_core.c
@@ -445,7 +445,8 @@ static int mv_ep_enable(struct usb_ep *_ep,
 	struct mv_dqh *dqh;
 	u16 max = 0;
 	u32 bit_pos, epctrlx, direction;
-	unsigned char zlt = 0, ios = 0, mult = 0;
+	const unsigned char zlt = 1;
+	unsigned char ios, mult;
 	unsigned long flags;
 
 	ep = container_of(_ep, struct mv_ep, ep);
@@ -465,8 +466,6 @@ static int mv_ep_enable(struct usb_ep *_ep,
 	 * disable HW zero length termination select
 	 * driver handles zero length packet through req->req.zero
 	 */
-	zlt = 1;
-
 	bit_pos = 1 << ((direction == EP_DIR_OUT ? 0 : 16) + ep->ep_num);
 
 	/* Check if the Endpoint is Primed */
@@ -481,16 +480,16 @@ static int mv_ep_enable(struct usb_ep *_ep,
 			(unsigned)bit_pos);
 		goto en_done;
 	}
+
 	/* Set the max packet length, interrupt on Setup and Mult fields */
+	ios = 0;
+	mult = 0;
 	switch (desc->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK) {
 	case USB_ENDPOINT_XFER_BULK:
-		zlt = 1;
-		mult = 0;
+	case USB_ENDPOINT_XFER_INT:
 		break;
 	case USB_ENDPOINT_XFER_CONTROL:
 		ios = 1;
-	case USB_ENDPOINT_XFER_INT:
-		mult = 0;
 		break;
 	case USB_ENDPOINT_XFER_ISOC:
 		/* Calculate transactions needed for high bandwidth iso */
-- 
2.12.0.rc1.440.g5b76565f74-goog