linux-kernel - [PATCH] usb: gadget: goku_udc: Fix mask and set operation on variable master

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Message-Id: <20210910163131.94796-1-colin.king@canonical.com>
Date:   Fri, 10 Sep 2021 17:31:31 +0100
From:   Colin King <colin.king@...onical.com>
To:     Felipe Balbi <balbi@...nel.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Evgeny Novikov <novikov@...ras.ru>, linux-usb@...r.kernel.org
Cc:     kernel-janitors@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH] usb: gadget: goku_udc: Fix mask and set operation on variable master

From: Colin Ian King <colin.king@...onical.com>

The variable master is being masked with ~MST_R_BITS however this
masked value is never used, the following updates to master are
assignments. I suspect the original intention was to mask out the
MST_R_BITS and then bit-wise or in the appropriate read bits rather
than perform an assignment. Fix this by using the |= operator rather
than a straight assignment.

Note that this code is pre-git history, so I can't find a sha for
it.

Addresses-Coverity: ("Unused value")
Signed-off-by: Colin Ian King <colin.king@...onical.com>
---
 drivers/usb/gadget/udc/goku_udc.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/usb/gadget/udc/goku_udc.c b/drivers/usb/gadget/udc/goku_udc.c
index 3e1267d38774..3757a772a55e 100644
--- a/drivers/usb/gadget/udc/goku_udc.c
+++ b/drivers/usb/gadget/udc/goku_udc.c
@@ -553,12 +553,12 @@ static int start_dma(struct goku_ep *ep, struct goku_request *req)
 
 		master &= ~MST_R_BITS;
 		if (unlikely(req->req.length == 0))
-			master = MST_RD_ENA | MST_RD_EOPB;
+			master |= MST_RD_ENA | MST_RD_EOPB;
 		else if ((req->req.length % ep->ep.maxpacket) != 0
 					|| req->req.zero)
-			master = MST_RD_ENA | MST_EOPB_ENA;
+			master |= MST_RD_ENA | MST_EOPB_ENA;
 		else
-			master = MST_RD_ENA | MST_EOPB_DIS;
+			master |= MST_RD_ENA | MST_EOPB_DIS;
 
 		ep->dev->int_enable |= INT_MSTRDEND;
 
-- 
2.32.0