linux-kernel - Re: [PATCH v3 1/8] drm/gpu: Remove dead checks on wbinvd_on_all

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Message-ID: <aHDQwa8FnZ33Rj8u@phenom.ffwll.local>
Date: Fri, 11 Jul 2025 10:52:17 +0200
From: Simona Vetter <simona.vetter@...ll.ch>
To: Sean Christopherson <seanjc@...gle.com>
Cc: Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...hat.com>,
	Borislav Petkov <bp@...en8.de>,
	Dave Hansen <dave.hansen@...ux.intel.com>, x86@...nel.org,
	Paolo Bonzini <pbonzini@...hat.com>,
	Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
	Maxime Ripard <mripard@...nel.org>,
	Thomas Zimmermann <tzimmermann@...e.de>,
	David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>,
	linux-kernel@...r.kernel.org, kvm@...r.kernel.org,
	dri-devel@...ts.freedesktop.org,
	Kevin Loughlin <kevinloughlin@...gle.com>,
	Tom Lendacky <thomas.lendacky@....com>,
	Kai Huang <kai.huang@...el.com>, Ingo Molnar <mingo@...nel.org>,
	Zheyun Shen <szy0127@...u.edu.cn>,
	Mingwei Zhang <mizhang@...gle.com>,
	Francesco Lavra <francescolavra.fl@...il.com>
Subject: Re: [PATCH v3 1/8] drm/gpu: Remove dead checks on
 wbinvd_on_all_cpus()'s return value

On Thu, May 22, 2025 at 04:37:25PM -0700, Sean Christopherson wrote:
> Remove the checks and associated pr_err() on wbinvd_on_all_cpus() failure,
> as the helper has unconditionally returned 0/success since commit
> caa759323c73 ("smp: Remove smp_call_function() and on_each_cpu() return
> values").
> 
> Signed-off-by: Sean Christopherson <seanjc@...gle.com>

I guess this'll all land through x86 trees, for that on this and the patch
from Peter to adjust the module exports to include drm and i915:

Acked-by: Simona Vetter <simona.vetter@...ll.ch>

Cheers, Sima
> ---
>  drivers/gpu/drm/drm_cache.c | 9 +++------
>  1 file changed, 3 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_cache.c b/drivers/gpu/drm/drm_cache.c
> index 7051c9c909c2..ea1d2d5d2c66 100644
> --- a/drivers/gpu/drm/drm_cache.c
> +++ b/drivers/gpu/drm/drm_cache.c
> @@ -93,8 +93,7 @@ drm_clflush_pages(struct page *pages[], unsigned long num_pages)
>  		return;
>  	}
>  
> -	if (wbinvd_on_all_cpus())
> -		pr_err("Timed out waiting for cache flush\n");
> +	wbinvd_on_all_cpus();
>  
>  #elif defined(__powerpc__)
>  	unsigned long i;
> @@ -139,8 +138,7 @@ drm_clflush_sg(struct sg_table *st)
>  		return;
>  	}
>  
> -	if (wbinvd_on_all_cpus())
> -		pr_err("Timed out waiting for cache flush\n");
> +	wbinvd_on_all_cpus();
>  #else
>  	WARN_ONCE(1, "Architecture has no drm_cache.c support\n");
>  #endif
> @@ -172,8 +170,7 @@ drm_clflush_virt_range(void *addr, unsigned long length)
>  		return;
>  	}
>  
> -	if (wbinvd_on_all_cpus())
> -		pr_err("Timed out waiting for cache flush\n");
> +	wbinvd_on_all_cpus();
>  #else
>  	WARN_ONCE(1, "Architecture has no drm_cache.c support\n");
>  #endif
> -- 
> 2.49.0.1151.ga128411c76-goog
> 

-- 
Simona Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch