Commit e7c22eeaff85 for kernel

commit e7c22eeaff8565d9a8374f320238c251ca31480b
Author: Geert Uytterhoeven <geert+renesas@glider.be>
Date:   Mon Jan 11 14:02:50 2021 +0100

    ALSA: fireface: Fix integer overflow in transmit_midi_msg()

    As snd_ff.rx_bytes[] is unsigned int, and NSEC_PER_SEC is 1000000000L,
    the second multiplication in

        ff->rx_bytes[port] * 8 * NSEC_PER_SEC / 31250

    always overflows on 32-bit platforms, truncating the result.  Fix this
    by precalculating "NSEC_PER_SEC / 31250", which is an integer constant.

    Note that this assumes ff->rx_bytes[port] <= 16777.

    Fixes: 19174295788de77d ("ALSA: fireface: add transaction support")
    Reviewed-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
    Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
    Link: https://lore.kernel.org/r/20210111130251.361335-2-geert+renesas@glider.be
    Signed-off-by: Takashi Iwai <tiwai@suse.de>

diff --git a/sound/firewire/fireface/ff-transaction.c b/sound/firewire/fireface/ff-transaction.c
index 7f82762ccc8c..ee7122c461d4 100644
--- a/sound/firewire/fireface/ff-transaction.c
+++ b/sound/firewire/fireface/ff-transaction.c
@@ -88,7 +88,7 @@ static void transmit_midi_msg(struct snd_ff *ff, unsigned int port)

 	/* Set interval to next transaction. */
 	ff->next_ktime[port] = ktime_add_ns(ktime_get(),
-				ff->rx_bytes[port] * 8 * NSEC_PER_SEC / 31250);
+			ff->rx_bytes[port] * 8 * (NSEC_PER_SEC / 31250));

 	if (quad_count == 1)
 		tcode = TCODE_WRITE_QUADLET_REQUEST;