Re: [PATCH v1 03/31] net/ntnic: add return code handling

[Stephen Hemminger <stephen@networkplumber.org>]

On Tue, 21 Jan 2025 18:07:41 +0100
Serhii Iliushyk <sil-plv@napatech.com> wrote:

> From: Danylo Vodopianov <dvo-plv@napatech.com>
> 
> CI found couple coverity problems which were fixed in this commit.
> 
> CID: 448984, 448982, 448975, 448969, 448968, 448967
> API usage errors  (BAD_COMPARE).
> 
> Add memcmp return value checking.
> 
> Coverity issue: 448984
> Fixes: 6e8b7f11205f ("net/ntnic: add categorizer (CAT) FPGA module")
> 
> Signed-off-by: Danylo Vodopianov <dvo-plv@napatech.com>
> ---
>  drivers/net/ntnic/include/hw_mod_backend.h | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/net/ntnic/include/hw_mod_backend.h b/drivers/net/ntnic/include/hw_mod_backend.h
> index f91a3ed058..40002f3343 100644
> --- a/drivers/net/ntnic/include/hw_mod_backend.h
> +++ b/drivers/net/ntnic/include/hw_mod_backend.h
> @@ -114,10 +114,10 @@ enum {
>  		typeof(be_module_reg) *temp_be_module = &(be_module_reg);                     \
>  		typeof(idx) tmp_idx = (idx);                                                  \
>  		typeof(cmp_idx) tmp_cmp_idx = (cmp_idx);                                      \
> -		if ((unsigned int)(tmp_idx) != (unsigned int)(tmp_cmp_idx)) {                     \
> -			(void)memcmp(temp_be_module + tmp_idx, &temp_be_module[tmp_cmp_idx],      \
> -				     sizeof(type));                                               \
> -		}                                                                                 \
> +		if ((unsigned int)(tmp_idx) != (unsigned int)(tmp_cmp_idx))                     \
> +			if (memcmp(temp_be_module + tmp_idx, &temp_be_module[tmp_cmp_idx], \
> +				sizeof(type)) == 0) \
> +				return 1;                                              \
>  	} while (0)
>  

Complex generic macros like this are brittle.
Adding a return in the middle of a loop means it will do unexpected exit of function??