Re: [PATCH] kdb: kdb_main: mark expected switch fall-throughs

From: Gustavo A. R. Silva
Date: Wed Aug 15 2018 - 11:32:46 EST


Hi Daniel,

On 8/15/18 9:34 AM, Daniel Thompson wrote:
> On 05/08/18 05:14, Gustavo A. R. Silva wrote:
>> In preparation to enabling -Wimplicit-fallthrough, mark switch cases
>> where we are expecting to fall through.
>>
>> Addresses-Coverity-ID: 115090 ("Missing break in switch")
>> Addresses-Coverity-ID: 115091 ("Missing break in switch")
>> Addresses-Coverity-ID: 114700 ("Missing break in switch")
>> Signed-off-by: Gustavo A. R. Silva <gustavo@xxxxxxxxxxxxxx>
>
> Adding fall through isn't wrong but its reasonable to ask why there is a complex hand unrolled loop here in the first place (and doubly so without a comment). The whole switch statement would be much clear expressed as:
>
> ÂÂÂÂfor (j=0; j<bytesperword; j++)
> ÂÂÂÂÂÂÂ *c++ = printable_char(*cp++);
> ÂÂÂÂaddr += bytesperword;
>

Yeah, I agree. I can send a patch for that.

Thanks for the feedback.
--
Gustavo

>
> Daniel.
>
>
>> ---
>> Â kernel/debug/kdb/kdb_main.c | 3 +++
>> Â 1 file changed, 3 insertions(+)
>>
>> diff --git a/kernel/debug/kdb/kdb_main.c b/kernel/debug/kdb/kdb_main.c
>> index 2ddfce8..2249645 100644
>> --- a/kernel/debug/kdb/kdb_main.c
>> +++ b/kernel/debug/kdb/kdb_main.c
>> @@ -1545,13 +1545,16 @@ static void kdb_md_line(const char *fmtstr, unsigned long addr,
>> ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ *c++ = printable_char(*cp++);
>> ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ *c++ = printable_char(*cp++);
>> ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ addr += 4;
>> +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ /* fall through */
>> ÂÂÂÂÂÂÂÂÂÂÂÂÂ case 4:
>> ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ *c++ = printable_char(*cp++);
>> ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ *c++ = printable_char(*cp++);
>> ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ addr += 2;
>> +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ /* fall through */
>> ÂÂÂÂÂÂÂÂÂÂÂÂÂ case 2:
>> ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ *c++ = printable_char(*cp++);
>> ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ addr++;
>> +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ /* fall through */
>> ÂÂÂÂÂÂÂÂÂÂÂÂÂ case 1:
>> ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ *c++ = printable_char(*cp++);
>> ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ addr++;
>>
>