From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mout-p-201.mailbox.org (mout-p-201.mailbox.org [80.241.56.171]) (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 2CB6E1917ED; Mon, 9 Feb 2026 08:20:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=80.241.56.171 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770625203; cv=none; b=XMhQKPcQer5+P/M3asTGYyDVHmZLpNALs4SO6FCP5O4xK9excl8LXPBRpqbkrlDXCmBGKsBNz5l+mDg1bIXI0GxDKStAlumZC3aeFdS6FV8//OVfHRM8tYuppZRCtU46VTxvaG81kzJkflPQu1iHxS01i+cHrV+JvCZao/2vLgY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770625203; c=relaxed/simple; bh=smzVsyxdwRXKIXKq6sMRkFmH+uR9PMBvUmQtPEwEyDs=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=haX0YZgaH2ZBMrXsSw/d45U4m7CVknlfjSFngt37A+uiYj/nx+1DUKJMp5IhgYge2QNKPbzzebCyy/WRIRRzV+LcNLHFzPLm/GwSo03vUcCGOb+klMxIXi2gi+81cFHyI0R3ykqZhTxGn5dxtEXDIz89HQiFISvgmI1LitPut08= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=mailbox.org; spf=pass smtp.mailfrom=mailbox.org; dkim=pass (2048-bit key) header.d=mailbox.org header.i=@mailbox.org header.b=IuRTF/pC; arc=none smtp.client-ip=80.241.56.171 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=mailbox.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=mailbox.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=mailbox.org header.i=@mailbox.org header.b="IuRTF/pC" Received: from smtp102.mailbox.org (smtp102.mailbox.org [10.196.197.102]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by mout-p-201.mailbox.org (Postfix) with ESMTPS id 4f8d0R5VL4z9tWy; Mon, 9 Feb 2026 09:19:51 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=mailbox.org; s=mail20150812; t=1770625191; h=from:from:reply-to: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=smzVsyxdwRXKIXKq6sMRkFmH+uR9PMBvUmQtPEwEyDs=; b=IuRTF/pCVt+GjI04jKHTG2lGXtrOR70tiEFYdmqWYc3P3jB2Fi1ErXKQQJ+Avy1xRpkJQD qa6u0tBzwP+N/B8o3BZsKHNcFMPsQSFVwge01IMTUqxpUHFNeBGmMKaegkhiQSxQzD0b+l E01ZgPqQ3yZm2/ZA2jQVna5G7h55xy4yNE+U9mu0HWn8a0pehPGhdLVT7bnPXZWIKs7U+5 Q4+ZSRYYTQZ7vllcYaEbjvrG7WDWtnfmJfE++Zd4TwJsthWknG5hjwBeK/uaI6tR12OthC V0MMsAgKzBHVQMbt+Drf7D91ZC4S7+YZO3oZmC0MYCpoZDmU9dISnSD6fA8eiA== Message-ID: Subject: Re: [RFC PATCH 2/4] rust: sync: Add dma_fence abstractions From: Philipp Stanner Reply-To: phasta@kernel.org To: Danilo Krummrich , Boris Brezillon Cc: Philipp Stanner , David Airlie , Simona Vetter , Alice Ryhl , Gary Guo , Benno Lossin , Christian =?ISO-8859-1?Q?K=F6nig?= , Daniel Almeida , Joel Fernandes , linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, rust-for-linux@vger.kernel.org Date: Mon, 09 Feb 2026 09:19:46 +0100 In-Reply-To: References: <20260203081403.68733-2-phasta@kernel.org> <20260203081403.68733-4-phasta@kernel.org> <20260205095727.4c3e2941@fedora> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MBO-RS-META: 8tun1zz3swrmw6s7exaf5jqmihwi9zxt X-MBO-RS-ID: f88b550d4582869a55f On Fri, 2026-02-06 at 11:23 +0100, Danilo Krummrich wrote: > On Thu Feb 5, 2026 at 9:57 AM CET, Boris Brezillon wrote: > > On Tue,=C2=A0 3 Feb 2026 09:14:01 +0100 > > Philipp Stanner wrote: > > Unfortunately, I don't know how to translate that in rust, but we > > need a way to check if any path code path does a DmaFence.signal(), > > go back to the entry point (for a WorkItem, that would be > > WorkItem::run() for instance), and make it a DmaFenceSignallingPath. > > Not only that, but we need to know all the deps that make it so > > this path can be called (if I take the WorkItem example, that would > > be the path that leads to the WorkItem being scheduled). >=20 > I think we need a guard object for this that is not Send, just like for a= ny > other lock. >=20 > Internally, those markers rely on lockdep, i.e. they just acquire and rel= ease a > "fake" lock. The guard object would be created through fence.begin_signalling(), wouldn'= t it? And when it drops you call dma_fence_end_signalling()? How would that ensure that the driver actually marks the signalling region = correctly? P.