[PATCH 2/2] Bluetooth: btmtk: size the ISO receive skb to hold header plus payload

[Chris Lu <chris.lu@mediatek.com>]

btmtk_recv_isopkt() allocates HCI_MAX_ISO_SIZE (251) bytes and stores the
4-byte HCI ISO header into the same skb, leaving only 247 bytes for the
payload. A Data_Total_Length of 248..251 would fail the skb_tailroom()
check and be dropped with -EILSEQ, taking the rest of the URB transfer
with it.

HCI_MAX_ISO_SIZE is the maximum payload length, not the maximum frame
length, so allocate HCI_MAX_ISO_SIZE + HCI_ISO_HDR_SIZE, matching how the
ACL path uses HCI_MAX_FRAME_SIZE (HCI_MAX_ACL_SIZE + 4).

Fixes: ceac1cb0259d ("Bluetooth: btusb: mediatek: add ISO data transmission functions")
Co-developed-by: Hao Qin <hao.qin@mediatek.com>
Signed-off-by: Hao Qin <hao.qin@mediatek.com>
Co-developed-by: Wenlong Tian <ot_wenlong.tian@mediatek.com>
Signed-off-by: Wenlong Tian <ot_wenlong.tian@mediatek.com>
Signed-off-by: Chris Lu <chris.lu@mediatek.com>
---
 drivers/bluetooth/btmtk.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/bluetooth/btmtk.c b/drivers/bluetooth/btmtk.c
index 869eb2176379..1b501b64d71f 100644
--- a/drivers/bluetooth/btmtk.c
+++ b/drivers/bluetooth/btmtk.c
@@ -1178,7 +1178,8 @@ static int btmtk_recv_isopkt(struct hci_dev *hdev, void *buffer, int count)
 		int len;
 
 		if (!skb) {
-			skb = bt_skb_alloc(HCI_MAX_ISO_SIZE, GFP_ATOMIC);
+			skb = bt_skb_alloc(HCI_MAX_ISO_SIZE + HCI_ISO_HDR_SIZE,
+					   GFP_ATOMIC);
 			if (!skb) {
 				err = -ENOMEM;
 				break;
-- 
2.45.2