[PATCH] usb: host: fhci-hcd: annotate PIPE_CONTROL switch case with fallthrough

From: Rasmus Villemoes <linux@rasmusvillemoes.dk>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Timur Tabi <timur@kernel.org>, Li Yang <leoyang.li@nxp.com>,
	Rasmus Villemoes <linux@rasmusvillemoes.dk>,
	"Gustavo A. R. Silva" <gustavo@embeddedor.com>
Cc: Anton Vorontsov <avorontsov@ru.mvista.com>,
	kbuild test robot <lkp@intel.com>,
	linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH] usb: host: fhci-hcd: annotate PIPE_CONTROL switch case with fallthrough
Date: Thu, 13 Feb 2020 09:54:00 +0100	[thread overview]
Message-ID: <20200213085401.27862-1-linux@rasmusvillemoes.dk> (raw)

After this was made buildable for something other than PPC32, kbuild
starts warning

drivers/usb/host/fhci-hcd.c:398:8: warning: this statement may fall
through [-Wimplicit-fallthrough=]

I don't know this code, but from the construction (initializing size
with 0 and explicitly using "size +=" in the PIPE_BULK case) I assume
that fallthrough is indeed intended.

Reported-by: kbuild test robot <lkp@intel.com>
Fixes: 5a35435ef4e6 (soc: fsl: qe: remove PPC32 dependency from CONFIG_QUICC_ENGINE)
Fixes: a035d552a93b (Makefile: Globally enable fall-through warning)
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
---

Two different Fixes: Obviously my 5a35435ef4e6 is the one that started
making kbuild complain, but that's just because apparently kbuild
doesn't cover a PPC32+USB_FHCI_HCD .config. Note for -stable folks,
just in case 5.3.y is still maintained somewhere: a035d552a93b
appeared in 5.3, but the #define fallthrough that I'm using here
wasn't introduced until 5.4 (294f69e662d15). So either ignore this,
make it /* fallthrough */, or backport 294f69e662d15 to 5.3.y as well.

 drivers/usb/host/fhci-hcd.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/usb/host/fhci-hcd.c b/drivers/usb/host/fhci-hcd.c
index 04733876c9c6..a8e1048278d0 100644
--- a/drivers/usb/host/fhci-hcd.c
+++ b/drivers/usb/host/fhci-hcd.c
@@ -396,6 +396,7 @@ static int fhci_urb_enqueue(struct usb_hcd *hcd, struct urb *urb,
 	case PIPE_CONTROL:
 		/* 1 td fro setup,1 for ack */
 		size = 2;
+		fallthrough;
 	case PIPE_BULK:
 		/* one td for every 4096 bytes(can be up to 8k) */
 		size += urb->transfer_buffer_length / 4096;
-- 
2.23.0

