Re: [PATCH] include/linux: Fix outdated comment on entry-common.h

[Thomas Gleixner <tglx@linutronix.de>]

On Sun, Jun 08 2025 at 19:48, Khalid Ali wrote:

'include/linux:' is not a valid prefix. See the documentation I pointed
you to in the other reply.

> From: Khalid Ali <khaliidcaliy@gmail.com>
>
> On most calls to this function, syscall_enter_from_user_mode_prepare()
> never get called as the comment indicates.
>
> Privious kernel version i used to see things happen as the function documentation
> indicated (syscall_enter_from_user_mode_prepare() called before
> syscall_enter_from_user_mode_work), however it seems now some things
> have changed which makes that point irrevelant. Most preparations that
> function does is handled manually by enter_from_user_mode() and
> some other places. So this makes it misleading.
>
> The point is remove strict function call indication on documentation as might be outdated
> one day in the future. There multiple places currently called
> syscall_enter_from_user_mode_work() without
> syscall_enter_from_user_mode_prepare() get called so that will make it
> condition not met.

That's again incomprehensible word salad.

You are right that the comment is not longer accurate, but your fixup
makes it even worse.

The real condition for calling this function is:

    1) enter_from_user_mode() has been invoked

    2) interrupts have been enabled

    3) Architecture specific work has been done

#1 must be the first thing. #2 and #3 have no ordering requirements.

syscall_enter_from_user_mode_prepare() does #1 and #2 together and in
the original implementation this was used in more places. So yes, the
comment is outdated, but it needs to describe the above requirements and
not something pulled out of thin air.

Thanks,

        tglx