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 7BD122222D9 for ; Tue, 25 Feb 2025 22:56:58 +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=1740524220; cv=none; b=IQWc/FPILkdbrtaLKCcRfwjsNt59S3+A6AIDmixrqaFPF0lFrcI2c1bE6avxJd19qbxKI9qTyFxx8uVYT/7Eg8aCMDB7IHsMyspYbFzV1cLoFDy+os23RmViZVStmaXXca/vjSZ+scB3BxZh63HxoEb4WLZHe6JR0RpM6CM4XGM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740524220; c=relaxed/simple; bh=GMPzrLo8gcPNCb+c1FxvtRjNMUFwtEy138bRJue0iJo=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=TLK15FdErky+EyGD0qF9nchx7Ya0SLhkt972A2dQW+tvll3jO9HAoNFDayqOBiP0mctgkfeZNB8i2i8kgNuJ8nOpJq+wq00sk/fw9zWXph6E7GE2MVD2h87iw4CAbdHK/svsQoW760yKPuRJaOsRWIBVO5pUTmxxPRbWeh7yZwg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none 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=AtYwDlaQ; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none 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="AtYwDlaQ" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1740524217; 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: in-reply-to:in-reply-to:references:references; bh=1MIExbY5lASb2t4DcFKWsWFPWydwcu/0GgTo18o9k4g=; b=AtYwDlaQ+oOfFIWBdpyRBOMHOU8/Jl9StX5oS4kUc+QqdOnDs4N4Josm5x7zUyh/yx23g8 QT2GSjvQI7O8Tgijgr2Xy6i32EQ0dWGLAMg9DfCosbamNJtGd7IVsYTr/QFjYeFWro84UD zJw5DzZ3YxvDkX8tD8DiT6jq5sXHxak= 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-453-gxNZfSALOQ-X3pKRAckKrQ-1; Tue, 25 Feb 2025 17:56:53 -0500 X-MC-Unique: gxNZfSALOQ-X3pKRAckKrQ-1 X-Mimecast-MFC-AGG-ID: gxNZfSALOQ-X3pKRAckKrQ_1740524212 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 3B5EE180034E; Tue, 25 Feb 2025 22:56:52 +0000 (UTC) Received: from fedora (unknown [10.72.116.21]) by mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id B6D5C300018D; Tue, 25 Feb 2025 22:56:46 +0000 (UTC) Date: Wed, 26 Feb 2025 06:56:41 +0800 From: Ming Lei To: Keith Busch Cc: Keith Busch , asml.silence@gmail.com, axboe@kernel.dk, linux-block@vger.kernel.org, io-uring@vger.kernel.org, bernd@bsbernd.com, csander@purestorage.com Subject: Re: [PATCHv5 09/11] ublk: zc register/unregister bvec Message-ID: References: <20250224213116.3509093-1-kbusch@meta.com> <20250224213116.3509093-10-kbusch@meta.com> Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.4 On Tue, Feb 25, 2025 at 09:35:30AM -0700, Keith Busch wrote: > On Tue, Feb 25, 2025 at 07:00:05PM +0800, Ming Lei wrote: > > On Mon, Feb 24, 2025 at 01:31:14PM -0800, Keith Busch wrote: > > > static inline bool ublk_dev_is_user_copy(const struct ublk_device *ub) > > > { > > > - return ub->dev_info.flags & UBLK_F_USER_COPY; > > > + return ub->dev_info.flags & (UBLK_F_USER_COPY | UBLK_F_SUPPORT_ZERO_COPY); > > > } > > > > I'd suggest to set UBLK_F_USER_COPY explicitly either from userspace or > > kernel side. > > > > One reason is that UBLK_F_UNPRIVILEGED_DEV mode can't work for both. > > In my reference implementation using ublksrv, I had the userspace > explicitly setting F_USER_COPY automatically if zero copy was requested. > Is that what you mean? Or do you need the kernel side to set both flags > if zero copy is requested too? Then the driver side has to validate the setting, and fail ZERO_COPY if F_USER_COPY isn't set. > > I actually have a newer diff for ublksrv making use of the SQE links. > I'll send that out with the next update since it looks like there will > need to be at least one more version. > > Relevant part from the cover letter, > https://lore.kernel.org/io-uring/20250203154517.937623-1-kbusch@meta.com/ OK, I will try to cook a ublk selftest in kernel tree so that the cross-subsystem change can be covered a bit easier. Thanks, Ming