Re: [PATCH v3 09/29] selftests/resctrl: Create cache_portion_size() helper

On Wed, 13 Dec 2023, Reinette Chatre wrote:

Hi Ilpo,

On 12/11/2023 4:18 AM, Ilpo Järvinen wrote:

...

+/*

• • cache_portion_size - Calculate the size of a cache portion
• • @cache_size: Total cache size in bytes
• • @portion_mask: Cache portion mask
• • @full_cache_mask: Full Cache Bit Mask (CBM) for the cache
• • Return: The size of the cache portion in bytes.
• */

+static inline int cache_portion_size(unsigned long cache_size,

• 		     unsigned long portion_mask,
  

• 		     unsigned long full_cache_mask)
  

+{

• return cache_size * count_bits(portion_mask) / count_bits(full_cache_mask);

+}

Even after you added the new zero check the static checker I tried was not able to recognize that this is safe. Could you please add a check to ensure that there will be no divide-by-zero here?

Okay. I also now noticed the return type is not what it should be.