From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 683622E426A for ; Thu, 16 Oct 2025 21:10:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760649027; cv=none; b=HJpqkNOUx1/DoCF+cSuEaYx4wiKx1A0AnlRfzrHmDXwd5PEECUDfdzIHvs97y/IaQM5AHtfxSSOLCO+IyW9BvQf57z1zKMFahU31dwEdWmAQePnwAYzDcat3Vc8y7xu6qHR6a6PPQDaor88aKzznnJU2R22I3LHb04Ch8EH10CM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760649027; c=relaxed/simple; bh=QrU4q3Vzt0MXcD2gDzySM0lrX65OYk3QyP55MPEUWLM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=KRz5xXo2fK1W6CEpZQtu3c5pc7yzqkwEAnloUoaxBrBLnDw9t1J477Zu4H7Fjjmo1OPHLCrtJZnSd7us050mLt3GmUaDC4bNNaKyceQX3kkoHc8Rlf2h3KLK1Oypp36D/4Bngp12tCYmC+pSLhYrrw5qj24PmlWJbfkMvRIjOJg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=GTNipxPp; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="GTNipxPp" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1760649024; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=Ij7DcA7oc5twnKbfaM76zg6OO8Y5d6E9HxWw6kPrfy8=; b=GTNipxPpynsrv4E7SPr7jKtWrjxGBHvXpspDFL0Gig+jp2YKyPBi68EWnwVcm+eolIrYkF TMObNRhNsVRHJT/BL4kQrU7W26lZbEjZfg5NdK+DqUGwWnYW9IaKHkrA3eb/t+FD4HwsVp K65QG0cSHotyRHIEW8T6mm1YO9oJr48= Received: from mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-659-YyiUp2BUOh2sxenhlo34EA-1; Thu, 16 Oct 2025 17:10:18 -0400 X-MC-Unique: YyiUp2BUOh2sxenhlo34EA-1 X-Mimecast-MFC-AGG-ID: YyiUp2BUOh2sxenhlo34EA_1760649016 Received: from mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.4]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 2952F180122A; Thu, 16 Oct 2025 21:10:16 +0000 (UTC) Received: from chopper.lan (unknown [10.22.80.252]) by mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 6956F30001BC; Thu, 16 Oct 2025 21:10:13 +0000 (UTC) From: Lyude Paul To: dri-devel@lists.freedesktop.org, rust-for-linux@vger.kernel.org, Daniel Almeida , Alice Ryhl Cc: David Airlie , Simona Vetter , Danilo Krummrich , Miguel Ojeda , Alex Gaynor , Boqun Feng , Gary Guo , =?UTF-8?q?Bj=C3=B6rn=20Roy=20Baron?= , Benno Lossin , Andreas Hindborg , Trevor Gross , Asahi Lina , Shankari Anand , linux-kernel@vger.kernel.org (open list) Subject: [PATCH v4 2/9] rust/drm: Add gem::impl_aref_for_gem_obj! Date: Thu, 16 Oct 2025 17:08:15 -0400 Message-ID: <20251016210955.2813186-3-lyude@redhat.com> In-Reply-To: <20251016210955.2813186-1-lyude@redhat.com> References: <20251016210955.2813186-1-lyude@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.4 In the future we're going to be introducing more GEM object types in rust then just gem::Object. Since all types of GEM objects have refcounting, let's introduce a macro that we can use in the gem crate in order to copy this boilerplate implementation for each type: impl_aref_for_gem_obj!(). Signed-off-by: Lyude Paul --- rust/kernel/drm/gem/mod.rs | 53 +++++++++++++++++++++++++++----------- 1 file changed, 38 insertions(+), 15 deletions(-) diff --git a/rust/kernel/drm/gem/mod.rs b/rust/kernel/drm/gem/mod.rs index 20c2769a8c9d6..981fbb931e952 100644 --- a/rust/kernel/drm/gem/mod.rs +++ b/rust/kernel/drm/gem/mod.rs @@ -15,6 +15,43 @@ }; use core::{ops::Deref, ptr::NonNull}; +/// A macro for implementing [`AlwaysRefCounted`] for any GEM object type. +/// +/// Since all GEM objects use the same refcounting scheme. +macro_rules! impl_aref_for_gem_obj { + ( + impl $( <$( $tparam_id:ident ),+> )? for $type:ty + $( + where + $( $bind_param:path : $bind_trait:path ),+ + )? + ) => { + // SAFETY: All gem objects are refcounted + unsafe impl $( <$( $tparam_id ),+> )? crate::types::AlwaysRefCounted for $type + $( + where + $( $bind_param : $bind_trait ),+ + )? + { + fn inc_ref(&self) { + // SAFETY: The existence of a shared reference guarantees that the refcount is + // non-zero. + unsafe { bindings::drm_gem_object_get(self.as_raw()) }; + } + + unsafe fn dec_ref(obj: core::ptr::NonNull) { + // SAFETY: `obj` is a valid pointer to an `Object`. + let obj = unsafe { obj.as_ref() }; + + // SAFETY: The safety requirements guarantee that the refcount is non-zero. + unsafe { bindings::drm_gem_object_put(obj.as_raw()) }; + } + } + }; +} + +pub(crate) use impl_aref_for_gem_obj; + /// A type alias for retrieving a [`Driver`]s [`DriverFile`] implementation from its /// [`DriverObject`] implementation. /// @@ -253,21 +290,7 @@ extern "C" fn free_callback(obj: *mut bindings::drm_gem_object) { } } -// SAFETY: Instances of `Object` are always reference-counted. -unsafe impl crate::types::AlwaysRefCounted for Object { - fn inc_ref(&self) { - // SAFETY: The existence of a shared reference guarantees that the refcount is non-zero. - unsafe { bindings::drm_gem_object_get(self.as_raw()) }; - } - - unsafe fn dec_ref(obj: NonNull) { - // SAFETY: `obj` is a valid pointer to an `Object`. - let obj = unsafe { obj.as_ref() }; - - // SAFETY: The safety requirements guarantee that the refcount is non-zero. - unsafe { bindings::drm_gem_object_put(obj.as_raw()) } - } -} +impl_aref_for_gem_obj!(impl for Object where T: DriverObject); impl super::private::Sealed for Object {} -- 2.51.0