On 1/14/21 2:59 AM, Vincent MAILHOL wrote:

On Tue. 14 Jan 2021 at 06:14, Marc Kleine-Budde [off-list ref] wrote:

quoted

If the length paramter in len2dlc() exceeds the size of the len2dlc array, we
return 0xF. This is equal to the last 16 members of the array.

This patch removes these members from the array, uses ARRAY_SIZE() for the
length check, and returns CANFD_MAX_DLC (which is 0xf).

Reviewed-by: Vincent Mailhol <redacted>
Link: https://lore.kernel.org/r/20210111141930.693847-9-mkl@pengutronix.de (local)
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
---
 drivers/net/can/dev/length.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/net/can/dev/length.c b/drivers/net/can/dev/length.c
index 5e7d481717ea..d695a3bee1ed 100644
--- a/drivers/net/can/dev/length.c
+++ b/drivers/net/can/dev/length.c

@@ -27,15 +27,13 @@ static const u8 len2dlc[] = {
        13, 13, 13, 13, 13, 13, 13, 13, /* 25 - 32 */
        14, 14, 14, 14, 14, 14, 14, 14, /* 33 - 40 */
        14, 14, 14, 14, 14, 14, 14, 14, /* 41 - 48 */
-       15, 15, 15, 15, 15, 15, 15, 15, /* 49 - 56 */
-       15, 15, 15, 15, 15, 15, 15, 15  /* 57 - 64 */
 };

 /* map the sanitized data length to an appropriate data length code */
 u8 can_fd_len2dlc(u8 len)
 {
-       if (unlikely(len > 64))
-               return 0xF;
+       if (len > ARRAY_SIZE(len2dlc))

Sorry but I missed an of-by-one issue when I did my first
review. Don't know why but it popped to my eyes this morning when
casually reading the emails.

ARRAY_SIZE(len2dlc) is 49. If len is between 0 and 48, use the
array, if len is greater *or equal* return CANFD_MAX_DLC.

Doh!

Looking for his brown paper bag,
Marc

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