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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 BDF9ECD343F for ; Thu, 7 May 2026 14:07:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=4nnZS8UhkRNBhCetvaI3gcfNb/5AGQqooHv4xQ6zj8I=; b=gI3y9kMcr8uqz9K6g3GasO+GVw FvHzP2WXYvNyKK/STZxj56w+9I5KEeXrR416W2/HmFWKG2CgroCDG8yiPLfXbt2p3ltafCntc7LB3 gqNETQJtS8xopWigL/3AD31f4wRPDNmZh5gEDE773KipLjE1sdRkmBFpPbjNhvCd86Y68lLl+vu6x 3G7YhK59akguNzUPOp7As3SpH4M4ADG5pzjIRJqfF5EjuU0ofEUi/Jzg9izdenBQcNHRHNGzMX+IH ZAQq+ozHkBNGJhanwZLEvXQFfSUe7kDF0ZSVLShppqgrrO1Kc6r82xzrIMqKjCrbBLInoqeZQQ/Ub EqiFD3WQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wKzNY-000000040mU-23ad; Thu, 07 May 2026 14:07:04 +0000 Received: from perceval.ideasonboard.com ([213.167.242.64]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1wKzNV-000000040lm-2rFw for linux-arm-kernel@lists.infradead.org; Thu, 07 May 2026 14:07:03 +0000 Received: from killaraus.ideasonboard.com (2001-14ba-70f3-e800--a06.rev.dnainternet.fi [IPv6:2001:14ba:70f3:e800::a06]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 25B22664; Thu, 7 May 2026 16:06:54 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1778162814; bh=XdoQSHYguWVmYaizw/9HEyu4QWIFpuURw2/1dzsB9v0=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=ZWeZiCKu+oIq14ANWhg9axIzcW14nW7oj/PYT+3BfRAGqbsCwMlfTrl+CGtMDhZrQ tXLV1TsYQALqmjgL5A0/3fYM5BRZOXZi9j7ReRC0s2HpoxszhmDFvl4+8ldreI27CM 6ia3Rtcw3CxN1hDJJYIIjf3Au2tq1XrN8aXaVc4c= Date: Thu, 7 May 2026 17:06:57 +0300 From: Laurent Pinchart To: Luca Ceresoli Cc: Andrzej Hajda , Neil Armstrong , Robert Foss , Jonas Karlman , Jernej Skrabec , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , Rob Clark , Dmitry Baryshkov , Abhinav Kumar , Jessica Zhang , Sean Paul , Marijn Suijten , Sumit Semwal , John Stultz , Tomi Valkeinen , Michal Simek , Hui Pu , Ian Ray , Thomas Petazzoni , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org, freedreno@lists.freedesktop.org, linux-arm-kernel@lists.infradead.org, Dmitry Baryshkov Subject: Re: [PATCH v5 01/11] drm/bridge: drm_bridge_put(): ignore ERR_PTR Message-ID: <20260507140657.GK1938994@killaraus.ideasonboard.com> References: <20260507-drm-bridge-alloc-getput-panel_or_bridge-v5-0-472b913b5cb7@bootlin.com> <20260507-drm-bridge-alloc-getput-panel_or_bridge-v5-1-472b913b5cb7@bootlin.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20260507-drm-bridge-alloc-getput-panel_or_bridge-v5-1-472b913b5cb7@bootlin.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260507_070701_867880_EDC9799D X-CRM114-Status: GOOD ( 17.81 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Thu, May 07, 2026 at 03:45:19PM +0200, Luca Ceresoli wrote: > Most functions returning a struct drm_bridge pointer currently return a > valid pointer or NULL, but this restricts their ability to return an error > code as an ERR_PTR describing the error kind. > > In preparation to have new APIs that can return a struct drm_bridge pointer > holding an ERR_PTR (and for those which already do) make drm_bridge_put() > ignore ERR_PTR values, just like it ignores NULL pointers. > > This will avoid annoying error checking in many places and the risk of > missing error checks. > > Suggested-by: Laurent Pinchart > Link: https://lore.kernel.org/all/20260318152533.GA633439@killaraus.ideasonboard.com/ > Suggested-by: Dmitry Baryshkov > Link: https://lore.kernel.org/all/omlnswxukeqgnatzdvooaashgkfcacjevkvbkm6xt33itgua2k@jcmzll2w6kdq/ > Reviewed-by: Dmitry Baryshkov > Signed-off-by: Luca Ceresoli Reviewed-by: Laurent Pinchart > --- > > Changes in v5: > - don't change drm_bridge_get(), only drm_bridge_put() has known use cases > > Changes in v4: > - removed incorrect change to drm_bridge_clear_and_put() kdoc > > Patch added in v2 > --- > drivers/gpu/drm/drm_bridge.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c > index d4b3478258ec..4aaea517b436 100644 > --- a/drivers/gpu/drm/drm_bridge.c > +++ b/drivers/gpu/drm/drm_bridge.c > @@ -300,7 +300,7 @@ EXPORT_SYMBOL(drm_bridge_get); > > /** > * drm_bridge_put - Release a bridge reference > - * @bridge: DRM bridge; if NULL this function does nothing > + * @bridge: DRM bridge; if NULL or an ERR_PTR this function does nothing > * > * This function decrements the bridge's reference count and frees the > * object if the reference count drops to zero. > @@ -310,7 +310,7 @@ EXPORT_SYMBOL(drm_bridge_get); > */ > void drm_bridge_put(struct drm_bridge *bridge) > { > - if (bridge) > + if (!IS_ERR_OR_NULL(bridge)) > kref_put(&bridge->refcount, __drm_bridge_free); > } > EXPORT_SYMBOL(drm_bridge_put); > -- Regards, Laurent Pinchart