As snd_fw_async_midi_port.consume_bytes is unsigned int, and
NSEC_PER_SEC is 1000000000L, the second multiplication in
port->consume_bytes * 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 port->consume_bytes <= 16777.
Fixes: 531f471834227d03 ("ALSA: firewire-lib/firewire-tascam: localize async midi port")
Signed-off-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
---
Compile-tested only.
I don't know the maximum transfer length of MIDI, but given it's an old
standard, I guess it's rather small. If it is larger than 16777, the
constant "8" should be replaced by "8ULL", to force 64-bit arithmetic.
---
sound/firewire/tascam/tascam-transaction.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/sound/firewire/tascam/tascam-transaction.c b/sound/firewire/tascam/tascam-transaction.c
index 90288b4b46379526..a073cece4a7d5e3a 100644
--- a/sound/firewire/tascam/tascam-transaction.c
+++ b/sound/firewire/tascam/tascam-transaction.c
@@ -209,7 +209,7 @@ static void midi_port_work(struct work_struct *work)
/* Set interval to next transaction. */
port->next_ktime = ktime_add_ns(ktime_get(),
- port->consume_bytes * 8 * NSEC_PER_SEC / 31250);
+ port->consume_bytes * 8 * (NSEC_PER_SEC / 31250));
/* Start this transaction. */
port->idling = false;
--
2.25.1
