linux-kernel - Re: [PATCH v11 09/14] entry: Rework syscall_exit_to_user_mode

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Message-ID: <87o6mbl82j.ffs@tglx>
Date: Fri, 30 Jan 2026 11:16:04 +0100
From: Thomas Gleixner <tglx@...nel.org>
To: Kevin Brodsky <kevin.brodsky@....com>, Jinjie Ruan
 <ruanjinjie@...wei.com>, catalin.marinas@....com, will@...nel.org,
 oleg@...hat.com, peterz@...radead.org, luto@...nel.org, shuah@...nel.org,
 kees@...nel.org, wad@...omium.org, deller@....de,
 akpm@...ux-foundation.org, charlie@...osinc.com, mark.rutland@....com,
 anshuman.khandual@....com, song@...nel.org, ryan.roberts@....com,
 thuth@...hat.com, ada.coupriediaz@....com, broonie@...nel.org,
 pengcan@...inos.cn, liqiang01@...inos.cn, kmal@...k.li,
 dvyukov@...gle.com, reddybalavignesh9979@...il.com,
 richard.weiyang@...il.com, linux-arm-kernel@...ts.infradead.org,
 linux-kernel@...r.kernel.org, linux-kselftest@...r.kernel.org
Subject: Re: [PATCH v11 09/14] entry: Rework
 syscall_exit_to_user_mode_work() for arch reuse

On Thu, Jan 29 2026 at 17:00, Kevin Brodsky wrote:
> On 29/01/2026 14:11, Jinjie Ruan wrote:
>>>> - * Calling convention is the same as for syscall_exit_to_user_mode() and it
>>>> - * returns with all work handled and interrupts disabled. The caller must
>>>> - * invoke exit_to_user_mode() before actually switching to user mode to
>>>> - * make the final state transitions. Interrupts must stay disabled between
>>>> - * return from this function and the invocation of exit_to_user_mode().
>>>> + * Calling convention is the same as for syscall_exit_to_user_mode(). The
>>>> + * caller must invoke local_irq_disable(), __exit_to_user_mode_prepare() and
>>> Shouldn't it be syscall_exit_to_user_mode_prepare() rather than
>>> __exit_to_user_mode_prepare()? The former has extra calls (e.g. rseq).
>> Perhaps we can just delete these comments — at present only generic
>> entry and arm64 use it, and nowhere else needs it; after the refactoring
>> the comments now seem rather unclear.
>
> Agreed, the comments are essentially describing what each function
> calls; considering how short they are, directly reading the code is
> probably easier.

No. Please keep them. There is more information in them than just the
pure 'what's' called.