From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (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 A851C428838 for ; Fri, 29 May 2026 18:37:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780079851; cv=none; b=K+s1IhEELFH6mcN26ZZEbfzv+aDCJgor1Pb7yocUrkBDb/A5QMGLcUl0v5vbSWhNe232ti/6izH2Eae3zus1Z3LLvs3BazccSApVqvDPtYOSUmXq9aw4rAjFk6CO0YGLk1IZilEOI/pYPPfpUyc03ZSan+Oikv1XW3tGfFAMFYs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780079851; c=relaxed/simple; bh=zMcjO7ihcoZk5wDoPdCIM8BBGLPEZ3tF+HA3S1Djtcs=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:content-type; b=b5pLfgO622YzQtfUAZj19WEl1s5d21QNLfYhP5tHEz8PdoheyNw/xqDrhXGauRuk0tgHcIHNMmY1souhhPWQmx9dMxRE6HVgvLl0Xb3w68g9ugj6KTQSx2y8du0C1tCBLfTqTJF0MkbhnWYuHMbKAiU3Vy3+x1sUg29TuL50+nQ= 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=CexDUM9F; arc=none smtp.client-ip=170.10.133.124 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="CexDUM9F" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1780079844; 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=a/7mQeFXAswtNMl7FgMd29VC1UT1l6NcPQS0ZRAe3HI=; b=CexDUM9FjeA2cgO8TUDVlJowqfyrq8MzBhvflSf30d5uDDyaN0QipJde4LKAEmMHq0j5wW 1gzeZIsI2JWL4QnR+sO0AQsnOJ7Ot2EzcDYsISglB649ZFKfUZ/s/ArB/JVF2nTHA2BszE TcmtNyOzooKCKLEkjCr9WqdJ0VLbgX0= Received: from mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-180-UD-9UEbMPOyM73EmN8uYHg-1; Fri, 29 May 2026 14:37:20 -0400 X-MC-Unique: UD-9UEbMPOyM73EmN8uYHg-1 X-Mimecast-MFC-AGG-ID: UD-9UEbMPOyM73EmN8uYHg_1780079837 Received: from mx-prod-int-10.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-10.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.95]) (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-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 2514F19560AA; Fri, 29 May 2026 18:37:17 +0000 (UTC) Received: from GoldenWind.redhat.com (unknown [10.22.89.101]) by mx-prod-int-10.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id B0ED91688; Fri, 29 May 2026 18:37:13 +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 v15 2/6] rust: drm: gem/shmem: Add DmaResvGuard helper Date: Fri, 29 May 2026 14:34:00 -0400 Message-ID: <20260529183702.677677-3-lyude@redhat.com> In-Reply-To: <20260529183702.677677-1-lyude@redhat.com> References: <20260529183702.677677-1-lyude@redhat.com> Precedence: bulk X-Mailing-List: rust-for-linux@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.6 on 10.30.177.95 X-Mimecast-MFC-PROC-ID: IKbb0vZIobIx-zz0RJ97fSNexc1mdE_sedum-Ihsdms_1780079837 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: 8bit content-type: text/plain; charset="US-ASCII"; x-default=true 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 --- 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 8b7de136ab1f9..a116b0752e46a 100644 --- a/rust/kernel/drm/gem/shmem.rs +++ b/rust/kernel/drm/gem/shmem.rs @@ -27,7 +27,10 @@ Deref, DerefMut, // }, - ptr::NonNull, + ptr::{ + self, + NonNull, // + }, }; use gem::{ BaseObjectPrivate, @@ -233,3 +236,29 @@ 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>(&'a Object); + +impl<'a, T: DriverObject> DmaResvGuard<'a, T> { + #[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> Drop for DmaResvGuard<'a, T> { + #[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