[PATCH 3/5] ALSA: firewire-lib: fix check for the size of isochronous packet payload

[Takashi Sakamoto]

The check for size of isochronous packet payload just cares of the size of
IR context payload without the size of CIP header.

Cc: <stable at vger.kernel.org>
Fixes: f11453c7cc01 ("ALSA: firewire-lib: use 16 bytes IR context header to separate CIP header")
Signed-off-by: Takashi Sakamoto <o-takashi at sakamocchi.jp>
---
 sound/firewire/amdtp-stream.c | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/sound/firewire/amdtp-stream.c b/sound/firewire/amdtp-stream.c
index 4e2f2bb7879f..b53971bf4b90 100644
--- a/sound/firewire/amdtp-stream.c
+++ b/sound/firewire/amdtp-stream.c
@@ -633,18 +633,24 @@ static int parse_ir_ctx_header(struct amdtp_stream *s, unsigned int cycle,
 			       unsigned int *syt, unsigned int index)
 {
 	const __be32 *cip_header;
+	unsigned int cip_header_size;
 	int err;
 
 	*payload_length = be32_to_cpu(ctx_header[0]) >> ISO_DATA_LENGTH_SHIFT;
-	if (*payload_length > s->ctx_data.tx.ctx_header_size +
-					s->ctx_data.tx.max_ctx_payload_length) {
+
+	if (!(s->flags & CIP_NO_HEADER))
+		cip_header_size = 8;
+	else
+		cip_header_size = 0;
+
+	if (*payload_length > cip_header_size + s->ctx_data.tx.max_ctx_payload_length) {
 		dev_err(&s->unit->device,
 			"Detect jumbo payload: %04x %04x\n",
-			*payload_length, s->ctx_data.tx.max_ctx_payload_length);
+			*payload_length, cip_header_size + s->ctx_data.tx.max_ctx_payload_length);
 		return -EIO;
 	}
 
-	if (!(s->flags & CIP_NO_HEADER)) {
+	if (cip_header_size > 0) {
 		cip_header = ctx_header + 2;
 		err = check_cip_header(s, cip_header, *payload_length,
 				       data_blocks, data_block_counter, syt);
-- 
2.27.0