Hi Guenter,
>>> Some static checker run by 0day reports a variableScope warning.
>>>
>>> net/bluetooth/smp.c:870:6: warning:
>>> The scope of the variable 'err' can be reduced. [variableScope]
>>>
>>> There is no need for two separate variables holding return values.
>>> Stick with the existing variable. While at it, don't pre-initialize
>>> 'ret' because it is set in each code path.
>>>
>>> tk_request() is supposed to return a negative error code on errors,
>>> not a bluetooth return code. The calling code converts the return
>>> value to SMP_UNSPECIFIED if needed.
>>>
>>> Fixes: 92516cd97fd4 ("Bluetooth: Always request for user confirmation for Just Works")
>>> Cc: Sonny Sasaka <sonnysasaka@xxxxxxxxxxxx>
>>> Signed-off-by: Guenter Roeck <linux@xxxxxxxxxxxx>
>>> ---
>>> net/bluetooth/smp.c | 9 ++++-----
>>> 1 file changed, 4 insertions(+), 5 deletions(-)
>>>
>>> diff --git a/net/bluetooth/smp.c b/net/bluetooth/smp.c
>>> index d0b695ee49f6..30e8626dd553 100644
>>> --- a/net/bluetooth/smp.c
>>> +++ b/net/bluetooth/smp.c
>>> @@ -854,8 +854,7 @@ static int tk_request(struct l2cap_conn *conn, u8 remote_oob, u8 auth,
>>> struct l2cap_chan *chan = conn->smp;
>>> struct smp_chan *smp = chan->data;
>>> u32 passkey = 0;
>>> - int ret = 0;
>>> - int err;
>>> + int ret;
>>>
>>> /* Initialize key for JUST WORKS */
>>> memset(smp->tk, 0, sizeof(smp->tk));
>>> @@ -887,12 +886,12 @@ static int tk_request(struct l2cap_conn *conn, u8 remote_oob, u8 auth,
>>> /* If Just Works, Continue with Zero TK and ask user-space for
>>> * confirmation */
>>> if (smp->method == JUST_WORKS) {
>>> - err = mgmt_user_confirm_request(hcon->hdev, &hcon->dst,
>>> + ret = mgmt_user_confirm_request(hcon->hdev, &hcon->dst,
>>> hcon->type,
>>> hcon->dst_type,
>>> passkey, 1);
>>> - if (err)
>>> - return SMP_UNSPECIFIED;
>>> + if (ret)
>>> + return ret;
>> I think there may be some miss match between expected types of error
>> codes here. The SMP error code type seems to be expected throughout
>> this code base, so this change would propagate a potential negative
>> value while the rest of the SMP protocol expects strictly positive
>> error codes.
>>
>
> Up to the patch introducing the SMP_UNSPECIFIED return value, tk_request()
> returned negative error codes, and all callers convert it to SMP_UNSPECIFIED.
>
> If tk_request() is supposed to return SMP_UNSPECIFIED on error, it should
> be returned consistently, and its callers don't have to convert it again.
maybe we need to fix that initial patch then.
Regards
Marcel
