Re: [PATCH] locking: Detect includes rwlock.h outside of spinlock.h

From: Sebastian Andrzej Siewior
Date: Thu Sep 08 2022 - 02:37:55 EST


On 2022-08-25 18:08:59 [+0200], To linux-kernel@xxxxxxxxxxxxxxx wrote:
> From: Michael S. Tsirkin <mst@xxxxxxxxxx>
>
> The check for __LINUX_SPINLOCK_H within rwlock.h (and other files)
> detects the direct include of the header file if it is at the very
> beginning of the include section.
> If it is listed later then chances are high that spinlock.h was already
> included (including rwlock.h) and the additional listing of rwlock.h
> will not cause any failure.
>
> On PREEMPT_RT this additional rwlock.h will lead to compile failures
> since it uses a different rwlock implementation.
>
> Add __LINUX_INSIDE_SPINLOCK_H to spinlock.h and check for this instead
> of __LINUX_SPINLOCK_H to detect wrong includes. This will help detect
> direct includes of rwlock.h with without PREEMPT_RT enabled.
>
> [ bigeasy: add remaining __LINUX_SPINLOCK_H user and rewrite
> commit description. ]
>
> Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
> ---
>
> This is to avoid patches like
> https://lkml.kernel.org/r/20220816074816.173227-1-bigeasy@xxxxxxxxxxxxx
>
> in the future which is not the first I sent…

polite *ping*

Sebastian