Re: [PATCH iwl-next] iavf: convert crit_section to DECLARE_BITMAP

[Simon Horman <horms@kernel.org>]

On Fri, May 15, 2026 at 08:38:36AM +0200, Aleksandr Loktionov wrote:
> struct iavf_adapter::crit_section is a bit-lock container indexed
> by values from enum iavf_critical_section_t (__IAVF_IN_REMOVE_TASK).
> It is manipulated exclusively through the kernel atomic bitops API:
> set_bit(), clear_bit(), test_bit(), test_and_set_bit().
> 
> It is declared as a bare 'unsigned long' and every call site passes
> '&adapter->crit_section'. That is functionally correct -- the bit
> index is a compile-time enum value well below BITS_PER_LONG so
> BIT_WORD(nr) is always 0 and only the singleton word is ever
> touched -- but it relies on layout coincidence rather than on the
> documented contract of the bitops API, which is defined in terms of
> 'unsigned long *' arrays.
> 
> Static analyzers that model the same contract flag every such call
> site with ARRAY_VS_SINGLETON because the address of a scalar is
> passed where an array pointer is expected.
> 
> Convert the field to a proper bitmap using DECLARE_BITMAP() sized by
> a new sentinel __IAVF_CRIT_SECTION_NBITS at the end of the enum. The
> underlying storage is unchanged (a single unsigned long word on every
> architecture Linux supports), so there is no functional or ABI change;
> the type simply becomes 'unsigned long[1]' which matches what the
> bitops API expects and silences the analyzer warnings permanently.
> 
> Drop the leading '&' at every call site, since arrays decay to
> pointers.
> 
> No functional change intended.
> 
> Suggested-by: Arkadiusz Kubalewski <arkadiusz.kubalewski@intel.com>
> Signed-off-by: Aleksandr Loktionov <aleksandr.loktionov@intel.com>

Reviewed-by: Simon Horman <horms@kernel.org>