On 2019/1/23 20:43, Greg KH wrote:
> On Wed, Jan 23, 2019 at 08:34:42PM +0800, YueHaibing wrote:
>> ./drivers/usb/misc/ftdi-elan.c:972:10-12: WARNING: possible condition with no effect (if == else)
>> ./drivers/usb/misc/ftdi-elan.c:983:9-11: WARNING: possible condition with no effect (if == else)
>> ./drivers/usb/misc/ftdi-elan.c:2052:11-13: WARNING: possible condition with no effect (if == else)
>>
>> Signed-off-by: YueHaibing <yuehaibing@xxxxxxxxxx>
>
> You can not just provide the output of a tool as a changelog text,
> sorry.
>
> Please explain what those lines mean, and why you are making the change
> that you are.
ok, will do that.
>
>> ---
>> drivers/usb/misc/ftdi-elan.c | 26 --------------------------
>> 1 file changed, 26 deletions(-)
>>
>> diff --git a/drivers/usb/misc/ftdi-elan.c b/drivers/usb/misc/ftdi-elan.c
>> index 76c718a..257efac 100644
>> --- a/drivers/usb/misc/ftdi-elan.c
>> +++ b/drivers/usb/misc/ftdi-elan.c
>> @@ -915,7 +915,6 @@ static int ftdi_elan_respond_engine(struct usb_ftdi *ftdi)
>> int bytes_read = 0;
>> int retry_on_empty = 1;
>> int retry_on_timeout = 3;
>> - int empty_packets = 0;
>> read:{
>> int packet_bytes = 0;
>> int retval = usb_bulk_msg(ftdi->udev,
>> @@ -960,31 +959,6 @@ read:{
>> dev_err(&ftdi->udev->dev, "error = %d with packet_bytes = %d with total %d bytes%s\n",
>> retval, packet_bytes, bytes_read, diag);
>> return retval;
>> - } else if (packet_bytes == 2) {
>> - unsigned char s0 = ftdi->bulk_in_buffer[0];
>> - unsigned char s1 = ftdi->bulk_in_buffer[1];
>> - empty_packets += 1;
>> - if (s0 == 0x31 && s1 == 0x60) {
>> - if (retry_on_empty-- > 0) {
>> - goto more;
>> - } else
>> - return 0;
>> - } else if (s0 == 0x31 && s1 == 0x00) {
>> - if (retry_on_empty-- > 0) {
>> - goto more;
>> - } else
>> - return 0;
>> - } else {
>> - if (retry_on_empty-- > 0) {
>> - goto more;
>> - } else
>> - return 0;
>> - }
>> - } else if (packet_bytes == 1) {
>> - if (retry_on_empty-- > 0) {
>> - goto more;
>> - } else
>> - return 0;
>
> Are you _sure_ that these lines are not needed and that the compiler is
> not really seeing them? As it doesn't look that way to me, what am I
> missing?
I checked and make sure that All these if/else if branch just do the same thing:
if (retry_on_empty-- > 0) {
goto more;
} else
return 0;
so it can be merged into the last else branch.
Also the variable 'empty_packets' doesn't use in any place, except for self increment
>
> thanks,
>
> greg k-h
>
> .
>
