Re: [RFC PATCH v2.2 02/28] mm/damon/core: embed damon_probe objects in damon_ctx

[SeongJae Park <sj@kernel.org>]

On Fri, 15 May 2026 01:17:07 +0000 sashiko-bot@kernel.org wrote:

> Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
> - [Low] Missing parentheses around the `ctx` macro argument in `damon_for_each_probe` and `damon_for_each_probe_safe`.
> --
> 
> commit e24428c998724cd2c79829fc347f7cc9804f966b
> Author: SeongJae Park <sj@kernel.org>
> 
> mm/damon/core: embed damon_probe objects in damon_ctx
> 
> This commit adds a linked list of damon_probe objects to damon_ctx. It also
> introduces initialization, cleanup, and helper macros to iterate over the new
> list.
> 
> > diff --git a/include/linux/damon.h b/include/linux/damon.h
> > index a8fff5325b010..3ba5a31b51769 100644
> > --- a/include/linux/damon.h
> > +++ b/include/linux/damon.h
> 
> [ ... ]
> 
> > @@ -879,6 +880,11 @@ static inline unsigned long damon_sz_region(struct damon_region *r)
> >  	return r->ar.end - r->ar.start;
> >  }
> >  
> > +#define damon_for_each_probe(p, ctx) \
> > +	list_for_each_entry(p, &ctx->probes, list)
> > +
> > +#define damon_for_each_probe_safe(p, next, ctx) \
> > +	list_for_each_entry_safe(p, next, &ctx->probes, list)
> 
> Should the ctx macro argument be wrapped in parentheses here?
> 
> Due to C operator precedence, if a caller passes an expression requiring a
> cast like (struct damon_ctx *)ptr, the macro would expand to:
> 
>     &(struct damon_ctx *)ptr->probes
> 
> Because the member access operator -> binds tighter than the cast, this
> evaluates as &(struct damon_ctx *)(ptr->probes). This can lead to
> unexpected compilation errors or incorrect pointer arithmetic.
> 
> Wrapping it as &(ctx)->probes would safely isolate the argument and match
> the pattern used by the existing damon_for_each_scheme macro in this file.

Nice suggestion, I will do so.


Thanks,
SJ

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