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Date:   Wed, 21 Dec 2022 21:08:01 +0530
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Subject: Re: [PATCH 04/10] drm/print: Fix support for NULL as first argument
 of drm_dbg_*
Content-Language: en-US, en-GB, hi-IN
To:     Thomas Zimmermann <tzimmermann@suse.de>
Cc:     dri-devel <dri-devel@lists.freedesktop.org>,
        linux-kernel <linux-kernel@vger.kernel.org>,
        Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
        Maxime Ripard <mripard@kernel.org>,
        David Airlie <airlied@gmail.com>,
        Daniel Vetter <daniel@ffwll.ch>
References: <cover.1671566741.git.code@siddh.me>
 <3ebf0d61ad5e82875a4493108602e62429306b14.1671566741.git.code@siddh.me>
 <e10cf9f1-af23-4355-7768-7d5010a28be0@suse.de>
From:   Siddh Raman Pant <code@siddh.me>
Message-ID: <16b08ba3-0d38-eb0f-8d4d-1da55ef38852@siddh.me>
In-Reply-To: <e10cf9f1-af23-4355-7768-7d5010a28be0@suse.de>
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On Wed, Dec 21 2022 at 14:38:08 +0530, Thomas Zimmermann wrote:
> Hi
>=20
> Am 20.12.22 um 21:16 schrieb Siddh Raman Pant:
>> Comments say macros DRM_DEBUG_* are deprecated in favor of
>> drm_dbg_*(NULL, ...), but they have broken support for it,
>> as the macro will result in `(NULL) ? (NULL)->dev : NULL`.
>>
>> Thus, fix them by casting input drm to a temporary struct ptr,
>> with the same convention as in __DRM_DEFINE_DBG_RATELIMITED.
>>
>> Signed-off-by: Siddh Raman Pant <code@siddh.me>
>> ---
>> =C2=A0 include/drm/drm_print.h | 89 ++++++++++++++++++++++++++++++++----=
-----
>> =C2=A0 1 file changed, 69 insertions(+), 20 deletions(-)
>>
>> diff --git a/include/drm/drm_print.h b/include/drm/drm_print.h
>> index a44fb7ef257f..53702d830291 100644
>> --- a/include/drm/drm_print.h
>> +++ b/include/drm/drm_print.h
>> @@ -486,26 +486,75 @@ void __drm_dev_dbg(struct _ddebug *desc, const str=
uct device *dev,
>> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 __drm_printk((drm), err, _ratelimited, "*=
ERROR* " fmt, ##__VA_ARGS__)
>> =C2=A0 =C2=A0 -#define drm_dbg_core(drm, fmt, ...)=C2=A0=C2=A0=C2=A0=C2=
=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=
=C2=A0=C2=A0=C2=A0 \
>> -=C2=A0=C2=A0=C2=A0 drm_dev_dbg((drm) ? (drm)->dev : NULL, DRM_UT_CORE, =
fmt, ##__VA_ARGS__)
> ...
>> +#define drm_dbg_core(drm, fmt, ...)=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=
=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 \
>> +({=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=
=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=
=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 \
>> +=C2=A0=C2=A0=C2=A0 const struct drm_device *drm_ =3D (drm);=C2=A0=C2=A0=
=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 \
>> +=C2=A0=C2=A0=C2=A0 drm_dev_dbg(drm_ ? drm_->dev : NULL, DRM_UT_CORE,=C2=
=A0=C2=A0=C2=A0 \
>> +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 fmt,=
 ##__VA_ARGS__);=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=
=A0=C2=A0 \
>> +})
>=20
> Instead of doing this for each drm_dbg_ macro, rather add an internal hel=
per that returns the device or NULL like this:
>=20
> static inline struct device *__drm_print_dev(struct drm_device *drm)
> {
> =C2=A0=C2=A0=C2=A0=C2=A0if (drm)
> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 return drm->dev;
> =C2=A0=C2=A0=C2=A0=C2=A0return NULL;
> }
>=20
> and change the macros to
>=20
> drm_dbg_core(drm, fmt, ...)
> =C2=A0=C2=A0=C2=A0=C2=A0drm_dev_dbg(__drm_print_dev(drm), DRM_UT_CORE, )
>=20
> and so on.
>=20
> Best regards
> Thomas

Sure, I'll send a v2.

Thanks,
Siddh