From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.6 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 90477C433E7 for ; Thu, 15 Oct 2020 04:22:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 294F922243 for ; Thu, 15 Oct 2020 04:22:07 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="aHj42zYf" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728330AbgJOEWG (ORCPT ); Thu, 15 Oct 2020 00:22:06 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47946 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728294AbgJOEWG (ORCPT ); Thu, 15 Oct 2020 00:22:06 -0400 Received: from mail-il1-x133.google.com (mail-il1-x133.google.com [IPv6:2607:f8b0:4864:20::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2D979C061755 for ; Wed, 14 Oct 2020 21:22:06 -0700 (PDT) Received: by mail-il1-x133.google.com with SMTP id z2so1104535ilh.11 for ; Wed, 14 Oct 2020 21:22:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:message-id:in-reply-to:references:subject :mime-version:content-transfer-encoding; bh=Somlrf0ExP10Fj8WfOm+BVLtpunVfzX2Kv+d9BC5xZ8=; b=aHj42zYfOm75QSl7bzVqS+Vis1sHH8s13SgshSRiF8kWtO2uudolFrp8BX9w866rD/ zAHh4B6XIgi5uh0CTbEza3BcEnNkzHECUJMBSAYu5c90VWnuBd/fiJAtwZSPEGVZizU+ DymhhppeB9q2kB6AHjZSQJ0zV97QI/CAa/SOhBJLhRBeoi65DY25peRw9QogLFunsqXM 85kL7V/j9qpvuWOiAepYGKPOshXs6NYSjT5lSJDhmbhKDUe4PnDMvQW2r3LUBk6+Tmjr QqMQLGJkWvFWNdoZ4DID/mNEvp29FA1xEsl4yeJE3FqypHYjHJ7tazZsXIWZzw+xGpiz cvJA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:message-id:in-reply-to :references:subject:mime-version:content-transfer-encoding; bh=Somlrf0ExP10Fj8WfOm+BVLtpunVfzX2Kv+d9BC5xZ8=; b=Hfb5ehxQKDn9cFb53NG2dmlg/XTRvw2rN3vbplJAM6+dR8PJSJzQRB/Cgh2t3EG9+c Qx6uK2Ljj36SD5Ws3/T0VqCIKX8Gq2C/m+/h68zvCJNKTDpIA52RE/labT3wcrVKFNBS 5CN5VXythdm4QMNpiYsbmRr64lmvopCEFDyMgEj/w+Ubt5AtZMOGKtiSRrjs16oMkoTK SFTPMgYy5sb1aO29U2x66BZqhMWoTMd+6mekBDIKl9LkArOKGxrhLkQ0ZmQwT+GmUaUL FyQDCznCf745OSky4kqc4aodXPD1Gt8fYV5vImPOzinTU7MICSlx2VUJ+yoUtgY9kYoj CDYA== X-Gm-Message-State: AOAM532vJkCaZx9tQW3U5MlciiCFKlrc6a87rlktFQQ83JTh8qnbytdT MT3rpcIgqltwFDI2ZAet09U= X-Google-Smtp-Source: ABdhPJzUGkHe50D4Cqn2Y8PBEyEehsG9cV4sqc9ytfBoyu3cJ6yB9CBF+54Nx6mLG+QyIAicQtO6mQ== X-Received: by 2002:a92:8404:: with SMTP id l4mr1953594ild.134.1602735725021; Wed, 14 Oct 2020 21:22:05 -0700 (PDT) Received: from localhost ([184.63.162.180]) by smtp.gmail.com with ESMTPSA id d7sm1454830ilr.31.2020.10.14.21.22.02 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 14 Oct 2020 21:22:04 -0700 (PDT) Date: Wed, 14 Oct 2020 21:21:56 -0700 From: John Fastabend To: Florian Lehner , john.fastabend@gmail.com Cc: ast@kernel.org, bpf@vger.kernel.org, daniel@iogearbox.net, dev@der-flo.net Message-ID: <5f87ce648edd5_b7602085a@john-XPS-13-9370.notmuch> In-Reply-To: <20201013144515.298647-1-dev@der-flo.net> References: <20200922190234.224161-1-dev@der-flo.net> <20201013144515.298647-1-dev@der-flo.net> Subject: RE: [PATCH bpf-next v2] bpf: Lift hashtab key_size limit Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org Florian Lehner wrote: > John Fastabend wrote: > > I think this is OK, but just curious is there a real use-case > > that has keys bigger than stack size or is this just an > > in-theory observation. > = > The use-case for this patch originates to implement allow/disallow > lists for files and file paths. The maximum length of file paths is > defined by PATH_MAX with 4096 chars including nul. > This limit exceeds=C2=A0MAX_BPF_STACK.=C2=A0 > = > Thanks, > Florian OK the check appears unnecessary. It seems a bit excessive to have such large keys though. Daniel, Alexei I couldn't find this patch in patchworks, not sure where it went. Acked-by: John Fastabend =