On 5/2/19 5:26 AM, Johan Hovold wrote:
> On Wed, May 01, 2019 at 04:33:29PM -0500, Gustavo A. R. Silva wrote:
>> In preparation to enabling -Wimplicit-fallthrough, mark switch
>> cases where we are expecting to fall through.
>>
>> This patch fixes the following warnings:
>>
>> drivers/usb/serial/io_edgeport.c: In function ‘process_rcvd_data’:
>> drivers/usb/serial/io_edgeport.c:1750:7: warning: this statement may fall through [-Wimplicit-fallthrough=]
>> if (bufferLength == 0) {
>> ^
>> drivers/usb/serial/io_edgeport.c:1755:3: note: here
>> case EXPECT_HDR2:
>> ^~~~
>> drivers/usb/serial/io_edgeport.c:1810:8: warning: this statement may fall through [-Wimplicit-fallthrough=]
>> if (bufferLength == 0) {
>> ^
>> drivers/usb/serial/io_edgeport.c:1816:3: note: here
>> case EXPECT_DATA: /* Expect data */
>> ^~~~
>>
>> Warning level 3 was used: -Wimplicit-fallthrough=3
>>
>> Notice that, in this particular case, the code comments are modified
>> in accordance with what GCC is expecting to find.
>>
>> This patch is part of the ongoing efforts to enable
>> -Wimplicit-fallthrough.
>>
>> Signed-off-by: Gustavo A. R. Silva <gustavo@xxxxxxxxxxxxxx>
>> ---
>> Changes in v2:
>> - Warning level 3 is now used: -Wimplicit-fallthrough=3
>> instead of warning level 2.
>> - All warnings in the switch statement are addressed now.
>>
>> Notice that these are the last remaining fall-through warnings
>> in the USB subsystem. :)
>
>> drivers/usb/serial/io_edgeport.c | 3 ++-
>> 1 file changed, 2 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/usb/serial/io_edgeport.c b/drivers/usb/serial/io_edgeport.c
>> index 4ca31c0e4174..7ad10328f4e2 100644
>> --- a/drivers/usb/serial/io_edgeport.c
>> +++ b/drivers/usb/serial/io_edgeport.c
>> @@ -1751,7 +1751,7 @@ static void process_rcvd_data(struct edgeport_serial *edge_serial,
>> edge_serial->rxState = EXPECT_HDR2;
>> break;
>> }
>> - /* otherwise, drop on through */
>> + /* Fall through - otherwise, drop on through */
>> case EXPECT_HDR2:
>> edge_serial->rxHeader2 = *buffer;
>> ++buffer;
>> @@ -1813,6 +1813,7 @@ static void process_rcvd_data(struct edgeport_serial *edge_serial,
>> }
>> /* Else, drop through */
>> }
>> + /* Fall through */
>> case EXPECT_DATA: /* Expect data */
>
> Looks like you forgot to take the original review feedback you got into
> account:
>
> https://lkml.kernel.org/r/87k1zf4k24.fsf@xxxxxxxxxxxxxxxxx
>
Oh, the thing is that the fall-through comments have to be placed at
the very bottom of the case. Also, based on that feedback, this time
I left the "Else, drop through" comment in place, so people can be
informed that such fall-through is conditional.
What do you think about this:
diff --git a/drivers/usb/serial/io_edgeport.c b/drivers/usb/serial/io_edgeport.c
index 4ca31c0e4174..52f27fc82563 100644
--- a/drivers/usb/serial/io_edgeport.c
+++ b/drivers/usb/serial/io_edgeport.c
@@ -1751,7 +1751,7 @@ static void process_rcvd_data(struct edgeport_serial *edge_serial,
edge_serial->rxState = EXPECT_HDR2;
break;
}
- /* otherwise, drop on through */
+ /* Fall through - otherwise, drop on through */
case EXPECT_HDR2:
edge_serial->rxHeader2 = *buffer;
++buffer;
@@ -1813,6 +1813,11 @@ static void process_rcvd_data(struct edgeport_serial *edge_serial,
}
/* Else, drop through */
}
+ /* Beware that, currently, there are at least three
+ * break statements in this case block, so the
+ * fall-through marked below is NOT unconditional.
+ */
+ /* Fall through */
case EXPECT_DATA: /* Expect data */
if (bufferLength < edge_serial->rxBytesRemaining) {
rxLen = bufferLength;
Thanks
--
Gustavo
