Re: [PATCH 2/4] sched_ext: Move scx_dispatch_sched() from sub.h to internal.h

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Low] Moving `scx_dispatch_sched()` to `internal.h` and including `cid.h` at the end creates a circular header dependency. `cid.h` includes `internal.h` at the top. When `cid.h` is included first by a C file, it triggers the inclusion of `internal.h`. The `#include "cid.h"` at the end of `internal.h` is skipped by the include guard. Consequently, `scx_dispatch_sched()` is parsed before the rest of `cid.h` has been processed, resulting in an 'implicit declaration of function' compiler error for `scx_cpu_arg()`. This violates the kernel coding standard requiring headers to be self-contained and independently compilable.
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--- Patch [2]: [PATCH 2/4] sched_ext: Move scx_dispatch_sched() from sub.h to internal.h ---
commit 6f0aa181637de48d619823a3e1db41e281070615
Author: Tejun Heo <tj@kernel.org>

sched_ext: Move scx_dispatch_sched() from sub.h to internal.h

This commit moves scx_dispatch_sched() from sub.h to internal.h,
and includes cid.h at the end of internal.h to support scx_cpu_arg().

> diff --git a/kernel/sched/ext/internal.h b/kernel/sched/ext/internal.h
> index d7a1d6a14ebf3..88b2a9b5d3ab2 100644
> --- a/kernel/sched/ext/internal.h
> +++ b/kernel/sched/ext/internal.h
> @@ -2289,4 +2289,115 @@ static inline struct scx_sched *scx_prog_sched(const struct bpf_prog_aux *aux)
>  static inline struct scx_sched *scx_parent(struct scx_sched *sch) { return NULL; }
>  #endif	/* CONFIG_EXT_SUB_SCHED */
>  
> +#include "cid.h"

[Severity: Low]
Does this create a circular header dependency between internal.h and cid.h?

If a C file includes cid.h before internal.h, cid.h includes internal.h
at the top. When processing internal.h, the #include "cid.h" here is
skipped by the include guard.

This causes scx_dispatch_sched() to be parsed before the rest of cid.h is
processed, which would result in an implicit declaration error for
scx_cpu_arg() further down in this function.

Could this cause build failures if headers are included in a different order
in the future?

> +
> +/*
> + * One user of this function is scx_bpf_dispatch() which can be called
> + * recursively as sub-sched dispatches nest. Always inline to reduce stack usage
> + * from the call frame.
> + */
> +static __always_inline bool
> +scx_dispatch_sched(struct scx_sched *sch, struct rq *rq,

[ ... ]

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Sashiko AI review · https://sashiko.dev/#/patchset/20260714230917.84158-1-tj@kernel.org?part=2