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 3C5FBCD6E57 for ; Wed, 3 Jun 2026 19:52:37 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 8FDBE11231B; Wed, 3 Jun 2026 19:52:36 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (1024-bit key; unprotected) header.d=redhat.com header.i=@redhat.com header.b="Bx+VDTp6"; dkim-atps=neutral Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by gabe.freedesktop.org (Postfix) with ESMTPS id 9C7C3112321 for ; Wed, 3 Jun 2026 19:52:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1780516352; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=r7Z/C3WKzX9d11zFSyCLO1QOj5Cg/fxzu0wnbss0mqw=; b=Bx+VDTp6AxOMm5wrvoqnsFzxSorymuQscGjmCIDWGy9zVJGqMKqTY9mulXxqlQmM34BzZm 1dsowJJhd30GYUMcYf+zEhDtizfM75EUQ+ZTJdjjDpBFAqTEl+FSvj0CE1hu7/ppsvmldI QaLGKWaoyyky5BdXqzsi4MPMZ9CPVGw= 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-357-SY1bvVhgOOuDGB9t24XwPA-1; Wed, 03 Jun 2026 15:52:28 -0400 X-MC-Unique: SY1bvVhgOOuDGB9t24XwPA-1 X-Mimecast-MFC-AGG-ID: SY1bvVhgOOuDGB9t24XwPA_1780516345 Received: from mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.111]) (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 7940C180034C; Wed, 3 Jun 2026 19:52:25 +0000 (UTC) Received: from GoldenWind.lan (unknown [10.22.81.203]) by mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id E2278180049F; Wed, 3 Jun 2026 19:52:21 +0000 (UTC) From: Lyude Paul To: dri-devel@lists.freedesktop.org, rust-for-linux@vger.kernel.org, nouveau@lists.freedesktop.org Cc: Alexandre Courbot , Gary Guo , =?UTF-8?q?Christian=20K=C3=B6nig?= , driver-core@lists.linux.dev, Miguel Ojeda , Maarten Lankhorst , Alice Ryhl , Simona Vetter , linux-kernel@vger.kernel.org, Sumit Semwal , linux-media@vger.kernel.org, "Rafael J . Wysocki" , Thomas Zimmermann , Maxime Ripard , David Airlie , Benno Lossin , linaro-mm-sig@lists.linaro.org, Danilo Krummrich , Mukesh Kumar Chaurasiya , Asahi Lina , Daniel Almeida , Lyude Paul , Greg Kroah-Hartman Subject: [PATCH v17 2/6] rust: drm: gem: shmem: Add DmaResvGuard helper Date: Wed, 3 Jun 2026 15:42:31 -0400 Message-ID: <20260603195210.693856-3-lyude@redhat.com> In-Reply-To: <20260603195210.693856-1-lyude@redhat.com> References: <20260603195210.693856-1-lyude@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.111 X-Mimecast-MFC-PROC-ID: VDcbFM3iqYVjWYmKYm_rG4KWt4no1w7wHXUx5WeXxVg_1780516345 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: 8bit content-type: text/plain; charset="US-ASCII"; x-default=true X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" Just a temporary holdover to make locking/unlocking the dma_resv lock much easier. Signed-off-by: Lyude Paul Co-authored-by: Alexandre Courbot Signed-off-by: Alexandre Courbot --- V17: * Fix format of commit message title rust/kernel/drm/gem/shmem.rs | 31 ++++++++++++++++++++++++++++++- 1 file changed, 30 insertions(+), 1 deletion(-) diff --git a/rust/kernel/drm/gem/shmem.rs b/rust/kernel/drm/gem/shmem.rs index 084b798ce795b..650c34dd8b7a4 100644 --- a/rust/kernel/drm/gem/shmem.rs +++ b/rust/kernel/drm/gem/shmem.rs @@ -30,7 +30,10 @@ Deref, DerefMut, // }, - ptr::NonNull, // + ptr::{ + self, + NonNull, // + }, }; use gem::{ BaseObjectPrivate, @@ -244,3 +247,29 @@ impl driver::AllocImpl for Object { dumb_map_offset: None, }; } + +/// Private helper-type for holding the `dma_resv` object for a GEM shmem object. +/// +/// When this is dropped, the `dma_resv` lock is dropped as well. +/// +// TODO: This should be replace with a WwMutex equivalent once we have such bindings in the kernel. +struct DmaResvGuard<'a, T: DriverObject, C: DeviceContext = Registered>(&'a Object); + +impl<'a, T: DriverObject, C: DeviceContext> DmaResvGuard<'a, T, C> { + #[inline(always)] + #[expect(unused)] + fn new(obj: &'a Object) -> Self { + // SAFETY: This lock is initialized throughout the lifetime of `object`. + unsafe { bindings::dma_resv_lock(obj.raw_dma_resv(), ptr::null_mut()) }; + + Self(obj) + } +} + +impl<'a, T: DriverObject, C: DeviceContext> Drop for DmaResvGuard<'a, T, C> { + #[inline(always)] + fn drop(&mut self) { + // SAFETY: We are releasing the lock grabbed during the creation of this object. + unsafe { bindings::dma_resv_unlock(self.0.raw_dma_resv()) }; + } +} -- 2.54.0