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 5cac26ab20b7105db6534c56b4fa577f1d2d4f21..e9209f44cb50046e99504b179cc71c553140b753 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);