From patchwork Wed Dec 20 21:45:01 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mina Almasry X-Patchwork-Id: 181788 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a05:7300:2483:b0:fb:cd0c:d3e with SMTP id q3csp28579dyi; Wed, 20 Dec 2023 13:46:38 -0800 (PST) X-Google-Smtp-Source: AGHT+IHI3fDG/lN9Dh153iIMuI2/WpF24G84qslbdflLVbByRPs7IAIIbyvdydkGp1lmowZi3O2J X-Received: by 2002:a50:d514:0:b0:553:2fce:a5f8 with SMTP id u20-20020a50d514000000b005532fcea5f8mr2327990edi.106.1703108798569; Wed, 20 Dec 2023 13:46:38 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1703108798; cv=none; d=google.com; s=arc-20160816; b=qLNOpYXCMgHbUii4QKoOwOwdbYEGRIO2Hxxw1ZHizbpvk/epyWN8SwpPvR6R1skvrf Vr/zCRiYNQL+Tqfv6aG2nWG+SWgwHv2Zda0tIzbu/+dwe0JXfeXwFtdGi5OzixZ4eYDj IYnW3mEy4qLZscUdUg1tWjH9e/ApS0WNky8YkTMgeLTsgZnU9qi/TVkoviCBtyRXFHJG dRxnmUJUM0RKaLersqGsqLq4knJs702hl3PFyaOd5mrDxluyymxfHgauBtL2xBtq0gM4 3Mesf2b8iPG5CPKTwD489weawde667Z8Q+eGGPZjldVURmZFOgTbFJpIhYpFhl5Higaf izbg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=cc:to:from:subject:message-id:references:mime-version :list-unsubscribe:list-subscribe:list-id:precedence:in-reply-to:date :dkim-signature; bh=9DyntanP2TiYwqFVgk0wpxjTNS8jI1v6Olu/+yXZqok=; fh=JlPK37Up5EiBiZMpR+3rbUHDZrxBspzZ+EmMm14SzR0=; b=O8MzceAHU33/AaN/A82Qdu5Ju84IUhp6OxempZx5bvQ9uzrrYYz4ZxysRFuiOEZndI Ksa0i9Mj8GkIKo/ug2bnTlWIIsIfAgWZpZ8rW6vc+4NgVuBgs2kRKqo+cf8GXlkwr11s cuLbE3oJkza6VRVtJlquDgA1bclaNMU7285N12OzF3+607RSETzZHo3fHjSB6mxe0VHZ EYc91SopEA8M1k2ZZliBweywIQcorLFOy0FO8o/J7Zg8b3g0qWeY9pdck95W+TrjR2LV dom1bLTxDL0yg04Rf0j4PSFX4CrrIGuNA2AChatbD+ArHyWKgZ18hrAltX0obYXMv0mK GaOA== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@google.com header.s=20230601 header.b=eOOSYvLB; spf=pass (google.com: domain of linux-kernel+bounces-7478-ouuuleilei=gmail.com@vger.kernel.org designates 2604:1380:4601:e00::3 as permitted sender) smtp.mailfrom="linux-kernel+bounces-7478-ouuuleilei=gmail.com@vger.kernel.org"; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=google.com Received: from am.mirrors.kernel.org (am.mirrors.kernel.org. [2604:1380:4601:e00::3]) by mx.google.com with ESMTPS id cx2-20020a05640222a200b00553a31da76fsi202382edb.184.2023.12.20.13.46.38 for (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 20 Dec 2023 13:46:38 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel+bounces-7478-ouuuleilei=gmail.com@vger.kernel.org designates 2604:1380:4601:e00::3 as permitted sender) client-ip=2604:1380:4601:e00::3; Authentication-Results: mx.google.com; dkim=pass header.i=@google.com header.s=20230601 header.b=eOOSYvLB; spf=pass (google.com: domain of linux-kernel+bounces-7478-ouuuleilei=gmail.com@vger.kernel.org designates 2604:1380:4601:e00::3 as permitted sender) smtp.mailfrom="linux-kernel+bounces-7478-ouuuleilei=gmail.com@vger.kernel.org"; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=google.com Received: from smtp.subspace.kernel.org (wormhole.subspace.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by am.mirrors.kernel.org (Postfix) with ESMTPS id 31E151F242E1 for ; Wed, 20 Dec 2023 21:46:38 +0000 (UTC) Received: from localhost.localdomain (localhost.localdomain [127.0.0.1]) by smtp.subspace.kernel.org (Postfix) with ESMTP id D65624BA98; Wed, 20 Dec 2023 21:45:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="eOOSYvLB" X-Original-To: linux-kernel@vger.kernel.org Received: from mail-yw1-f201.google.com (mail-yw1-f201.google.com [209.85.128.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A624C4AF79 for ; Wed, 20 Dec 2023 21:45:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--almasrymina.bounces.google.com Received: by mail-yw1-f201.google.com with SMTP id 00721157ae682-5e20c9c4080so3734947b3.3 for ; Wed, 20 Dec 2023 13:45:13 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1703108713; x=1703713513; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=9DyntanP2TiYwqFVgk0wpxjTNS8jI1v6Olu/+yXZqok=; b=eOOSYvLBWn2T2H42i1DVzx2QNCS5zbBTluHDw7IYKLT7zZuZ9VE+KFuleyoQQ2KuLo cLqSqjic02BvPpsb6y/lWJHyL5mMWnlisBYGyiSEFASJ9LYu/cawnw8DdbxGTN92ZZf+ AJ2bfCzLkl4Gbmd1yX7ABKNp0D1QFD9/SjhU1CzgrKlDsWb99dUCqxRvvsADnnb553nI orhYUU/KGyzuBLR74NuXfTQXJImADxImGCYep/pt4ElS294/Lv4YpWdMG6s09m5INTZd DcmaCvwX4dSo8HLhxCS4Dbz42FmpsCaJmb1/6IGZdVMpKZzqCpm+tCAh7xI8bBNQXXh7 X4YA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1703108713; x=1703713513; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=9DyntanP2TiYwqFVgk0wpxjTNS8jI1v6Olu/+yXZqok=; b=h7XCEqu0sNNPRm/8VAvRNtn+zNPgEytBSmDBJPth86lz0WAVRgg+1QI9wcfTwEbqEy VXix3jn3OWFcNRviWuPJC1qE2UZiSyFE8Qm6DAcSyLwKilwowM0Zx1olAsAh+OEdYXWL lS7uEE3ni46O3L/fioadoA2MG2TIUHIi83c6n2MnEm/yAtabQ3czE+9JN46FR0RM6HTQ YJIwu9qIy82yM/4S2nE5TEwLAP9k0ERRSc+o+djH4KssQA1g+1BbqZfYf+eSPl9w30pq O5wRo45GgPg9/ytS4OBPxWNPwUCnJwM/jk4BVqOeoo+url9CXgj1OCTwqzvp3JBFeDV+ WJdA== X-Gm-Message-State: AOJu0YyIa41wjGKJFXpVrI42gXvX+BgO7N8vA+k46LgaNpXBo6iWnaAG fGuoMeWNKu7GdLAdmt3/aB2qya+vRF2qxIYR/NOuqLEcl4OswgOyUmfeopmSE//Eaixwl95FQBY w3T5FiZb1WUScmEYFsGj+NOK9PbCySHmZ/MLvppqKQoqv6Vjf96rwZc7sP5x2RBnLqRGCRjIwg0 5c0l7mcno= X-Received: from almasrymina.svl.corp.google.com ([2620:15c:2c4:200:13cc:a33:a435:3fe9]) (user=almasrymina job=sendgmr) by 2002:a25:a28a:0:b0:dbd:b756:983a with SMTP id c10-20020a25a28a000000b00dbdb756983amr151334ybi.9.1703108712675; Wed, 20 Dec 2023 13:45:12 -0800 (PST) Date: Wed, 20 Dec 2023 13:45:01 -0800 In-Reply-To: <20231220214505.2303297-1-almasrymina@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20231220214505.2303297-1-almasrymina@google.com> X-Mailer: git-send-email 2.43.0.472.g3155946c3a-goog Message-ID: <20231220214505.2303297-3-almasrymina@google.com> Subject: [PATCH net-next v3 2/3] net: introduce abstraction for network memory From: Mina Almasry To: linux-kernel@vger.kernel.org, netdev@vger.kernel.org, kvm@vger.kernel.org, virtualization@lists.linux.dev Cc: Mina Almasry , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Stefan Hajnoczi , Stefano Garzarella , David Howells , Jason Gunthorpe , " =?utf-8?q?Christian_K=C3=B6nig?= " , Shakeel Butt , Yunsheng Lin , Willem de Bruijn X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: 1785839011866903119 X-GMAIL-MSGID: 1785839011866903119 Add the netmem_ref type, an abstraction for network memory. To add support for new memory types to the net stack, we must first abstract the current memory type. Currently parts of the net stack use struct page directly: - page_pool - drivers - skb_frag_t Originally the plan was to reuse struct page* for the new memory types, and to set the LSB on the page* to indicate it's not really a page. However, for compiler type checking we need to introduce a new type. netmem_ref is introduced to abstract the underlying memory type. Currently it's a no-op abstraction that is always a struct page underneath. In parallel there is an undergoing effort to add support for devmem to the net stack: https://lore.kernel.org/netdev/20231208005250.2910004-1-almasrymina@google.com/ Signed-off-by: Mina Almasry --- v3: - Modify struct netmem from a union of struct page + new types to an opaque netmem_ref type. I went with: +typedef void *__bitwise netmem_ref; rather than this that Jakub recommended: +typedef unsigned long __bitwise netmem_ref; Because with the latter the compiler issues warnings to cast NULL to netmem_ref. I hope that's ok. - Add some function docs. v2: - Use container_of instead of a type cast (David). --- include/net/netmem.h | 41 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 41 insertions(+) create mode 100644 include/net/netmem.h diff --git a/include/net/netmem.h b/include/net/netmem.h new file mode 100644 index 000000000000..edd977326203 --- /dev/null +++ b/include/net/netmem.h @@ -0,0 +1,41 @@ +/* SPDX-License-Identifier: GPL-2.0 + * + * Network memory + * + * Author: Mina Almasry + */ + +#ifndef _NET_NETMEM_H +#define _NET_NETMEM_H + +/** + * typedef netmem_ref - a nonexistent type marking a reference to generic + * network memory. + * + * A netmem_ref currently is always a reference to a struct page. This + * abstraction is introduced so support for new memory types can be added. + * + * Use the supplied helpers to obtain the underlying memory pointer and fields. + */ +typedef void *__bitwise netmem_ref; + +/* This conversion fails (returns NULL) if the netmem_ref is not struct page + * backed. + * + * Currently struct page is the only possible netmem, and this helper never + * fails. + */ +static inline struct page *netmem_to_page(netmem_ref netmem) +{ + return (struct page *)netmem; +} + +/* Converting from page to netmem is always safe, because a page can always be + * a netmem. + */ +static inline netmem_ref page_to_netmem(struct page *page) +{ + return (netmem_ref)page; +} + +#endif /* _NET_NETMEM_H */