usb: acm: fix the computation of the number of data bits

commit 301a29da upstream.

The current code assumes that CSIZE is 0000060, which appears to be
wrong on some arches (such as powerpc).
Signed-off-by: Nicolas Boullis <nboullis@debian.org>
Acked-by: Oliver Neukum <oneukum@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

drivers/usb/class/cdc-acm.c

@@ -760,10 +760,6 @@ static const __u32 acm_tty_speed[] = {
 	2500000, 3000000, 3500000, 4000000
 };
 
-static const __u8 acm_tty_size[] = {
-	5, 6, 7, 8
-};
-
 static void acm_tty_set_termios(struct tty_struct *tty,
 						struct ktermios *termios_old)
 {
@@ -780,7 +776,21 @@ static void acm_tty_set_termios(struct tty_struct *tty,
 	newline.bParityType = termios->c_cflag & PARENB ?
 				(termios->c_cflag & PARODD ? 1 : 2) +
 				(termios->c_cflag & CMSPAR ? 2 : 0) : 0;
-	newline.bDataBits = acm_tty_size[(termios->c_cflag & CSIZE) >> 4];
+	switch (termios->c_cflag & CSIZE) {
+	case CS5:
+		newline.bDataBits = 5;
+		break;
+	case CS6:
+		newline.bDataBits = 6;
+		break;
+	case CS7:
+		newline.bDataBits = 7;
+		break;
+	case CS8:
+	default:
+		newline.bDataBits = 8;
+		break;
+	}
 	/* FIXME: Needs to clear unsupported bits in the termios */
 	acm->clocal = ((termios->c_cflag & CLOCAL) != 0);