From 395f41e2cdac63e7581fb9574e5ac0f02556e34a Mon Sep 17 00:00:00 2001
From: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Date: Thu, 13 May 2021 21:56:50 +0900
Subject: [PATCH] ALSA: firewire-lib: fix check for the size of isochronous packet payload
Git-commit: 395f41e2cdac63e7581fb9574e5ac0f02556e34a
Patch-mainline: v5.13-rc3
References: git-fixes

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@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@sakamocchi.jp>
Link: https://lore.kernel.org/r/20210513125652.110249-4-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Iwai <tiwai@suse.de>

---
 sound/firewire/amdtp-stream.c |   14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

--- a/sound/firewire/amdtp-stream.c
+++ b/sound/firewire/amdtp-stream.c
@@ -621,18 +621,24 @@ static int parse_ir_ctx_header(struct am
 {
 	unsigned int dbc;
 	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, &dbc, syt);