From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 AE6712DC331; Sun, 12 Apr 2026 16:36:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776011792; cv=none; b=Ox8PRGVovlDm2qBNP2hDYFBkUQoMF0N3MSoAukET4nYrQNKRdBTQoTns0mhI/F+QvKqOYs99uKh+Gg3qvHXkOeksubrmFzSqWDkkM+H6zznceZVT8FDTPsEgrEOlxIcQ9BuqGv6AcbHYKJrxGnt0BdjfbBfueoHYJIL2k8bCuQc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776011792; c=relaxed/simple; bh=4QjD8Gil0KJjjLLI+MuDfyRITEVYm2cDNV44JrR0LNg=; h=Date:From:To:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=m6/6rGBUOq83Xv+HNHZ1TNeiHS0eFitUuKlkdy2NRMB/lHUb36KNrZVZowNaWwtcS1kmbkhG6/SilBVLJ5spwK6MkX0TKAfA/Kuera44XcM5ZQWAdhkh6H6B5VhH5UdF6bJp2ozAn1qkVO87hTtHsF5xvAkWXOmj7klYKQMQwL4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=kon2JfsS; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="kon2JfsS" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E3517C19424; Sun, 12 Apr 2026 16:36:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1776011792; bh=4QjD8Gil0KJjjLLI+MuDfyRITEVYm2cDNV44JrR0LNg=; h=Date:From:To:Subject:References:In-Reply-To:From; b=kon2JfsSdeJ0OJF/zLZ76ZzAGIUgLO6vVq7rQECZyWzXP85caRpaC7JatXxGYVtzw Zf0CPHhlMlEJVJnz+Oy/JyIhvBd0UrslvunFuHFcl+lR0TrI5MZmBN4NUILVoLnmC/ Ho6A3Unlb7faFK5SrMJm5CEE982WUybkF4Q0f63wvYXVAaUuHTy+BluhrTGzrrwUQl eI8uAqFNVn3K/lXa0W1+ufV++gdszRoU7L+WprW4J+YTjs+R3kHLif3cCnSey9Ydln 7yAgbVeORxW5yyitxlszVOjz6rWCtVLN6bKBSnvAulSn/jIK+4aJnrTsxhQJSigChF XSPabJVLS/5yQ== Date: Sun, 12 Apr 2026 19:36:26 +0300 From: Leon Romanovsky To: Christoph Hellwig , Jens Axboe , drbd-dev@lists.linbit.com, linux-kernel@vger.kernel.org, Lars Ellenberg , Philipp Reisner , linux-block@vger.kernel.org, Joel Colledge , linux-rdma@vger.kernel.org, Jason Gunthorpe Subject: Re: [PATCH 06/20] drbd: add RDMA transport implementation Message-ID: <20260412163626.GE21470@unreal> References: <20260327223820.2244227-1-christoph.boehmwalder@linbit.com> <20260327223820.2244227-7-christoph.boehmwalder@linbit.com> Precedence: bulk X-Mailing-List: linux-rdma@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: On Wed, Apr 08, 2026 at 02:01:43PM +0200, Christoph Böhmwalder wrote: > On Tue, Apr 07, 2026 at 10:42:55PM -0700, Christoph Hellwig wrote: > > You really need to add the RDMA mailing list before adding new RDMA > > code. I'll try to review the bits I still remember, but you also > > need a maintainer ACK. > > Thanks for the hint and your detailed feedback. I'll address all that > in v2 (plus some other similar fixes). Thanks Christoph for adding us. I fast-forward read the patch and immediately spotted two things: 1. Please don't call directly to HW drivers. + err = device->ops.query_device(device, &dev_attr, &uhw); + if (err) { + tr_err(transport, "ib_query_device: %d\n", err); + return err; + } 2. Add any missing API to RDMA subsystem, don't leave it to the users: + } else if (reduced) { + /* ib_create_qp() may return -ENOMEM if max_send_wr or max_recv_wr are + too big. Unfortunately there is no way to find the working maxima. + http://www.rdmamojo.com/2012/12/21/ibv_create_qp/ + Suggests "Trial end error" to find the maximal number. */ + + tr_warn(transport, "Needed to adjust buffer sizes for HCA\n"); + tr_warn(transport, "rcvbuf = %d sndbuf = %d \n", + path->flow[DATA_STREAM].rx_descs_max * DRBD_SOCKET_BUFFER_SIZE, + path->flow[DATA_STREAM].tx_descs_max * DRBD_SOCKET_BUFFER_SIZE); + tr_warn(transport, "It is recommended to apply this change to the configuration\n"); + } + Thanks > > Thanks, > Christoph