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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Malcolm Priestley <tvboxspy@gmail.com>
Subject: [PATCH 5.4 41/78] staging: vt6656: Fix non zero logical return of, usb_control_msg
Date:   Tue, 14 Jan 2020 11:01:15 +0100
Message-Id: <20200114094359.096762080@linuxfoundation.org>
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From: Malcolm Priestley <tvboxspy@gmail.com>

commit 58c3e681b04dd57c70d0dcb7b69fe52d043ff75a upstream.

Starting with commit 59608cb1de1856
("staging: vt6656: clean function's error path in usbpipe.c")
the usb control functions have returned errors throughout driver
with only logical variable checking.

However, usb_control_msg return the amount of bytes transferred
this means that normal operation causes errors.

Correct the return function so only return zero when transfer
is successful.

Cc: stable <stable@vger.kernel.org> # v5.3+
Signed-off-by: Malcolm Priestley <tvboxspy@gmail.com>
Link: https://lore.kernel.org/r/08e88842-6f78-a2e3-a7a0-139fec960b2b@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/staging/vt6656/usbpipe.c |    8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

--- a/drivers/staging/vt6656/usbpipe.c
+++ b/drivers/staging/vt6656/usbpipe.c
@@ -59,7 +59,9 @@ int vnt_control_out(struct vnt_private *
 
 	kfree(usb_buffer);
 
-	if (ret >= 0 && ret < (int)length)
+	if (ret == (int)length)
+		ret = 0;
+	else
 		ret = -EIO;
 
 end_unlock:
@@ -103,7 +105,9 @@ int vnt_control_in(struct vnt_private *p
 
 	kfree(usb_buffer);
 
-	if (ret >= 0 && ret < (int)length)
+	if (ret == (int)length)
+		ret = 0;
+	else
 		ret = -EIO;
 
 end_unlock: