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From:   Jani Nikula <jani.nikula@linux.intel.com>
To:     Nathan Chancellor <nathan@kernel.org>,
        Nathan Huckleberry <nhuck@google.com>
Cc:     Dan Carpenter <error27@gmail.com>, llvm@lists.linux.dev,
        Joonas Lahtinen <joonas.lahtinen@linux.intel.com>,
        Rodrigo Vivi <rodrigo.vivi@intel.com>,
        Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>,
        David Airlie <airlied@linux.ie>,
        Daniel Vetter <daniel@ffwll.ch>,
        Nick Desaulniers <ndesaulniers@google.com>,
        Tom Rix <trix@redhat.com>,
        Matt Roper <matthew.d.roper@intel.com>,
        Lucas De Marchi <lucas.demarchi@intel.com>,
        intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH] drm/i915: Fix return type of mode_valid function hook
In-Reply-To: <YyEP7W/yZAyhNtTX@dev-arch.thelio-3990X>
Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo
References: <20220913205531.155046-1-nhuck@google.com>
 <YyEP7W/yZAyhNtTX@dev-arch.thelio-3990X>
Date:   Thu, 15 Sep 2022 10:39:26 +0300
Message-ID: <87v8pp13yp.fsf@intel.com>
MIME-Version: 1.0
Content-Type: text/plain
Precedence: bulk

On Tue, 13 Sep 2022, Nathan Chancellor <nathan@kernel.org> wrote:
> On Tue, Sep 13, 2022 at 01:55:27PM -0700, Nathan Huckleberry wrote:
>> All of the functions used for intel_dvo_dev_ops.mode_valid have a return
>> type of enum drm_mode_status, but the mode_valid field in the struct
>> definition has a return type of int.
>> 
>> The mismatched return type breaks forward edge kCFI since the underlying
>> function definitions do not match the function hook definition.
>> 
>> The return type of the mode_valid field should be changed from int to
>> enum drm_mode_status.
>> 
>> Reported-by: Dan Carpenter <error27@gmail.com>
>> Link: https://github.com/ClangBuiltLinux/linux/issues/1703
>> Cc: llvm@lists.linux.dev
>> Signed-off-by: Nathan Huckleberry <nhuck@google.com>
>
> Reviewed-by: Nathan Chancellor <nathan@kernel.org>

Thanks for the patch and reviews, pushed to drm-intel-next.

BR,
Jani.

>
>> ---
>>  drivers/gpu/drm/i915/display/intel_dvo_dev.h | 4 ++--
>>  1 file changed, 2 insertions(+), 2 deletions(-)
>> 
>> diff --git a/drivers/gpu/drm/i915/display/intel_dvo_dev.h b/drivers/gpu/drm/i915/display/intel_dvo_dev.h
>> index d96c3cc46e50..50205f064d93 100644
>> --- a/drivers/gpu/drm/i915/display/intel_dvo_dev.h
>> +++ b/drivers/gpu/drm/i915/display/intel_dvo_dev.h
>> @@ -75,8 +75,8 @@ struct intel_dvo_dev_ops {
>>  	 *
>>  	 * \return MODE_OK if the mode is valid, or another MODE_* otherwise.
>>  	 */
>> -	int (*mode_valid)(struct intel_dvo_device *dvo,
>> -			  struct drm_display_mode *mode);
>> +	enum drm_mode_status (*mode_valid)(struct intel_dvo_device *dvo,
>> +					   struct drm_display_mode *mode);
>>  
>>  	/*
>>  	 * Callback for preparing mode changes on an output
>> -- 
>> 2.37.2.789.g6183377224-goog
>> 

-- 
Jani Nikula, Intel Open Source Graphics Center