ALSA: fireworks: fix wrong return count shorter than expected by 4 bytes

commit eb9d84b0ffe39893cb23b0b6712bbe3637fa25fa upstream.

ALSA fireworks driver has a bug in its initial state to return count
shorter than expected by 4 bytes to userspace applications when handling
response frame for Echo Audio Fireworks transaction. It's due to missing
addition of the size for the type of event in ALSA firewire stack.

Fixes: 555e8a8f7f14 ("ALSA: fireworks: Add command/response functionality into hwdep interface")
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20220424102428.21109-1-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/sound/firewire/fireworks/fireworks_hwdep.c b/sound/firewire/fireworks/fireworks_hwdep.c
index 2e1d9a23920c0c3ebf4b6edda5019b672dab4e82..09ba61f60699b91be5c56c2ea09a32df73d94aca 100644 (file)
--- a/sound/firewire/fireworks/fireworks_hwdep.c
+++ b/sound/firewire/fireworks/fireworks_hwdep.c
@@ -35,6 +35,7 @@ hwdep_read_resp_buf(struct snd_efw *efw, char __user *buf, long remained,
        type = SNDRV_FIREWIRE_EVENT_EFW_RESPONSE;
        if (copy_to_user(buf, &type, sizeof(type)))
                return -EFAULT;
+       count += sizeof(type);
        remained -= sizeof(type);
        buf += sizeof(type);