Re: [PATCH] RFC: Bluetooth: missed cpu_to_le16 conversion in hci_init4_req

On Wed, Oct 16, 2019 at 08:42:48PM +0200, Marcel Holtmann wrote:

Hi Simon,

quoted

quoted

It looks like in hci_init4_req() the request is being
initialised from cpu-endian data but the packet is specified
to be little-endian. This causes an warning from sparse due
to __le16 to u16 conversion.

Fix this by using cpu_to_le16() on the two fields in the packet.

net/bluetooth/hci_core.c:845:27: warning: incorrect type in assignment (different base types)
net/bluetooth/hci_core.c:845:27:    expected restricted __le16 [usertype] tx_len
net/bluetooth/hci_core.c:845:27:    got unsigned short [usertype] le_max_tx_len
net/bluetooth/hci_core.c:846:28: warning: incorrect type in assignment (different base types)
net/bluetooth/hci_core.c:846:28:    expected restricted __le16 [usertype] tx_time
net/bluetooth/hci_core.c:846:28:    got unsigned short [usertype] le_max_tx_time

Signed-off-by: Ben Dooks <redacted>
---
Cc: Marcel Holtmann <marcel@holtmann.org>
Cc: Johan Hedberg <redacted>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: linux-bluetooth@vger.kernel.org
Cc: netdev@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
---
net/bluetooth/hci_core.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
index 04bc79359a17..b2559d4bed81 100644
--- a/net/bluetooth/hci_core.c
+++ b/net/bluetooth/hci_core.c

@@ -842,8 +842,8 @@ static int hci_init4_req(struct hci_request *req, unsigned long opt)

	if (hdev->le_features[0] & HCI_LE_DATA_LEN_EXT) {
		struct hci_cp_le_write_def_data_len cp;

-		cp.tx_len = hdev->le_max_tx_len;
-		cp.tx_time = hdev->le_max_tx_time;
+		cp.tx_len = cpu_to_le16(hdev->le_max_tx_len);
+		cp.tx_time = cpu_to_le16(hdev->le_max_tx_time);

I would suggest that the naming of the le_ fields of struct hci_dev
implies that the values stored in those fields should be little endian
(but those that are more than bone byte wide are not).

the le_ stands for Low Energy and not for Little Endian.

Thanks, in that case I have no objections.