From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 9F013C433F5 for ; Wed, 16 Mar 2022 08:04:45 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id DF3FC10E7BD; Wed, 16 Mar 2022 08:04:41 +0000 (UTC) Received: from mga07.intel.com (mga07.intel.com [134.134.136.100]) by gabe.freedesktop.org (Postfix) with ESMTPS id 3F29510E7B3; Wed, 16 Mar 2022 08:04:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1647417880; x=1678953880; h=from:to:cc:subject:in-reply-to:references:date: message-id:mime-version:content-transfer-encoding; bh=ud3ZGW99NB2N9YtEXOyV+ImHcKiBaY2G/sDAEK31UH8=; b=T63nVg9YbghWWkRa6TTqNPN1w8vK7qB1k6yGzr8p0rmrNXDI9kw9lBaC +ILGU+T3l22Xb2YKm5yUhtDZ2dgUOCnO0f1R8tunY10aAfhvEeRy2klTX 5c5t5eqJe/2wFLCb3IfPvI4OHtDGcZL6BNuDci0ymSTxpMR/HNZRfz2t1 QU9TEcVu6ekH8NxjuPZitSXp1BBGzN80rIjF4Cou4/Ajf4C1eu4/UzBYg noTqh4ATSDyjxPteCnkFJTVw2omXzokiTyZZP9r5czKOJF0PCltERQsLf ZiLa0vZxNZ8aCrE3QdLKtW8qDkZl4fZX7+fM8qz9YvrnZ26C18Xig8hEn Q==; X-IronPort-AV: E=McAfee;i="6200,9189,10286"; a="319736929" X-IronPort-AV: E=Sophos;i="5.90,186,1643702400"; d="scan'208";a="319736929" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by orsmga105.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 16 Mar 2022 01:04:39 -0700 X-IronPort-AV: E=Sophos;i="5.90,186,1643702400"; d="scan'208";a="557333296" Received: from jgarrosx-mobl1.amr.corp.intel.com (HELO localhost) ([10.252.34.45]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 16 Mar 2022 01:04:37 -0700 From: Jani Nikula To: Ville Syrjala , dri-devel@lists.freedesktop.org In-Reply-To: <20220218100403.7028-20-ville.syrjala@linux.intel.com> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo References: <20220218100403.7028-1-ville.syrjala@linux.intel.com> <20220218100403.7028-20-ville.syrjala@linux.intel.com> Date: Wed, 16 Mar 2022 10:04:34 +0200 Message-ID: <871qz2pbl9.fsf@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Subject: Re: [Intel-gfx] [PATCH 19/22] drm/i915: Use drm_mode_copy() X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: intel-gfx@lists.freedesktop.org Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" On Fri, 18 Feb 2022, Ville Syrjala wrote: > From: Ville Syrj=C3=A4l=C3=A4 > > struct drm_display_mode embeds a list head, so overwriting > the full struct with another one will corrupt the list > (if the destination mode is on a list). Use drm_mode_copy() > instead which explicitly preserves the list head of > the destination mode. > > Even if we know the destination mode is not on any list > using drm_mode_copy() seems decent as it sets a good > example. Bad examples of not using it might eventually > get copied into code where preserving the list head > actually matters. > > Obviously one case not covered here is when the mode > itself is embedded in a larger structure and the whole > structure is copied. But if we are careful when copying > into modes embedded in structures I think we can be a > little more reassured that bogus list heads haven't been > propagated in. > > @is_mode_copy@ > @@ > drm_mode_copy(...) > { > ... > } > > @depends on !is_mode_copy@ > struct drm_display_mode *mode; > expression E, S; > @@ > ( > - *mode =3D E > + drm_mode_copy(mode, &E) > | > - memcpy(mode, E, S) > + drm_mode_copy(mode, E) > ) > > @depends on !is_mode_copy@ > struct drm_display_mode mode; > expression E; > @@ > ( > - mode =3D E > + drm_mode_copy(&mode, &E) > | > - memcpy(&mode, E, S) > + drm_mode_copy(&mode, E) > ) > > @@ > struct drm_display_mode *mode; > @@ > - &*mode > + mode > > Signed-off-by: Ville Syrj=C3=A4l=C3=A4 Reviewed-by: Jani Nikula > --- > drivers/gpu/drm/i915/display/intel_display.c | 15 ++++++++++----- > 1 file changed, 10 insertions(+), 5 deletions(-) > > diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/d= rm/i915/display/intel_display.c > index 74c5a99ab276..661e36435793 100644 > --- a/drivers/gpu/drm/i915/display/intel_display.c > +++ b/drivers/gpu/drm/i915/display/intel_display.c > @@ -5506,8 +5506,10 @@ intel_crtc_copy_uapi_to_hw_state_modeset(struct in= tel_atomic_state *state, >=20=20 > crtc_state->hw.enable =3D crtc_state->uapi.enable; > crtc_state->hw.active =3D crtc_state->uapi.active; > - crtc_state->hw.mode =3D crtc_state->uapi.mode; > - crtc_state->hw.adjusted_mode =3D crtc_state->uapi.adjusted_mode; > + drm_mode_copy(&crtc_state->hw.mode, > + &crtc_state->uapi.mode); > + drm_mode_copy(&crtc_state->hw.adjusted_mode, > + &crtc_state->uapi.adjusted_mode); > crtc_state->hw.scaling_filter =3D crtc_state->uapi.scaling_filter; >=20=20 > intel_crtc_copy_uapi_to_hw_state_nomodeset(state, crtc); > @@ -5584,9 +5586,12 @@ copy_bigjoiner_crtc_state_modeset(struct intel_ato= mic_state *state, > memset(&slave_crtc_state->hw, 0, sizeof(slave_crtc_state->hw)); > slave_crtc_state->hw.enable =3D master_crtc_state->hw.enable; > slave_crtc_state->hw.active =3D master_crtc_state->hw.active; > - slave_crtc_state->hw.mode =3D master_crtc_state->hw.mode; > - slave_crtc_state->hw.pipe_mode =3D master_crtc_state->hw.pipe_mode; > - slave_crtc_state->hw.adjusted_mode =3D master_crtc_state->hw.adjusted_m= ode; > + drm_mode_copy(&slave_crtc_state->hw.mode, > + &master_crtc_state->hw.mode); > + drm_mode_copy(&slave_crtc_state->hw.pipe_mode, > + &master_crtc_state->hw.pipe_mode); > + drm_mode_copy(&slave_crtc_state->hw.adjusted_mode, > + &master_crtc_state->hw.adjusted_mode); > slave_crtc_state->hw.scaling_filter =3D master_crtc_state->hw.scaling_f= ilter; >=20=20 > copy_bigjoiner_crtc_state_nomodeset(state, slave_crtc); --=20 Jani Nikula, Intel Open Source Graphics Center