2018-08-05 04:16:06

by Gustavo A. R. Silva

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

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 <[email protected]>
---
kernel/debug/kdb/kdb_main.c | 3 +++
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,
*c++ = printable_char(*cp++);
*c++ = printable_char(*cp++);
addr += 4;
+ /* fall through */
case 4:
*c++ = printable_char(*cp++);
*c++ = printable_char(*cp++);
addr += 2;
+ /* fall through */
case 2:
*c++ = printable_char(*cp++);
addr++;
+ /* fall through */
case 1:
*c++ = printable_char(*cp++);
addr++;
--
2.7.4

2018-08-15 14:35:53

by Daniel Thompson

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

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 <[email protected]>

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:

for (j=0; j<bytesperword; j++)
*c++ = printable_char(*cp++);
addr += bytesperword;


Daniel.


> ---
> kernel/debug/kdb/kdb_main.c | 3 +++
> 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,
> *c++ = printable_char(*cp++);
> *c++ = printable_char(*cp++);
> addr += 4;
> + /* fall through */
> case 4:
> *c++ = printable_char(*cp++);
> *c++ = printable_char(*cp++);
> addr += 2;
> + /* fall through */
> case 2:
> *c++ = printable_char(*cp++);
> addr++;
> + /* fall through */
> case 1:
> *c++ = printable_char(*cp++);
> addr++;
>

2018-08-15 15:34:06

by Gustavo A. R. Silva

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

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 <[email protected]>
>
> 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:
>
>     for (j=0; j<bytesperword; j++)
>         *c++ = printable_char(*cp++);
>     addr += bytesperword;
>

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

Thanks for the feedback.
--
Gustavo

>
> Daniel.
>
>
>> ---
>>   kernel/debug/kdb/kdb_main.c | 3 +++
>>   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,
>>                   *c++ = printable_char(*cp++);
>>                   *c++ = printable_char(*cp++);
>>                   addr += 4;
>> +                /* fall through */
>>               case 4:
>>                   *c++ = printable_char(*cp++);
>>                   *c++ = printable_char(*cp++);
>>                   addr += 2;
>> +                /* fall through */
>>               case 2:
>>                   *c++ = printable_char(*cp++);
>>                   addr++;
>> +                /* fall through */
>>               case 1:
>>                   *c++ = printable_char(*cp++);
>>                   addr++;
>>
>