From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (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 E838F1D698 for ; Thu, 5 Oct 2023 14:42:48 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="UQ/8vbZu" Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 300ED29B35 for ; Thu, 5 Oct 2023 07:42:13 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1696516933; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=EcYpFc5fQ2y3uLxjaGAy7lsrM21+5zwRHwXefFI3p3Q=; b=UQ/8vbZuGoQ9t158NccRXBVxt79EErtuzCofWy6hSIISWc6s+8Vq1VXPaRE6OzELi2AAhM gR4EoYTrwTuEYhCDHA5jgTcB7T7nSxIBc+oTTpVJ9gtxbAvQh5WFuLi/bfp3K8JCfPLY66 +h6jilfhuBiA6Gtlzy7TWrS76idN5hM= Received: from mail-ej1-f71.google.com (mail-ej1-f71.google.com [209.85.218.71]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-175-vjSSkmL7M4GhkEwbLrB0TA-1; Thu, 05 Oct 2023 06:39:09 -0400 X-MC-Unique: vjSSkmL7M4GhkEwbLrB0TA-1 Received: by mail-ej1-f71.google.com with SMTP id a640c23a62f3a-9b989422300so19028966b.0 for ; Thu, 05 Oct 2023 03:39:09 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1696502348; x=1697107148; h=mime-version:user-agent:content-transfer-encoding:references :in-reply-to:date:cc:to:from:subject:message-id:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=EcYpFc5fQ2y3uLxjaGAy7lsrM21+5zwRHwXefFI3p3Q=; b=vmrt1XiP4QyhSMByNlmZ/k6M9Z6KYcq6nIOVUo5My3PMcc/gZWjYaWKhbMJuIXLNPy EfIdIJZHWIbDg1YSI2w3llsb1JDxnEP/UcFkw3EeQGuFlPIjlpNndyVEN+bJx+zp8GaS ohYUf7N2GlEtEWisqRB4RQ008v9CDbE2ekVN+S0yjfYiLeA3z8ekq7w9H/cJUAiRuPnP AyHa8h7iW0ra7KGq/WL81BziKltOEXEqX7Y3Agy0UMQB2yKAPmJTniCPnCmp6GsaRzkg cUVJ7e465rvpkPU83DOKH+IklF/k68Amo9Ee6KXEafy6qoqYsW9WWzacPavZSXKtAR/G OZnA== X-Gm-Message-State: AOJu0Ywne+SBvq9Fqfdiw64i+JH4na7DSf2q3a2VUotWwg2ZtC+fDzCq xRWs7sxUKwowXJR1CcjdqtL7HNTATt00aZiXqjwLv+k7Y7wLilaV786mysNdYn3PNtMsIy1HabR +8CO7HMnjYQw9xFZU X-Received: by 2002:a05:6402:5191:b0:51e:5dd8:fc59 with SMTP id q17-20020a056402519100b0051e5dd8fc59mr4227639edd.1.1696502348314; Thu, 05 Oct 2023 03:39:08 -0700 (PDT) X-Google-Smtp-Source: AGHT+IEXoi9NQo5thKA2z7QAg6O6iVK7LWh7JCWMxNO5nWP25rBMF90nlazkgDGpx4ETuytneK118Q== X-Received: by 2002:a05:6402:5191:b0:51e:5dd8:fc59 with SMTP id q17-20020a056402519100b0051e5dd8fc59mr4227628edd.1.1696502347918; Thu, 05 Oct 2023 03:39:07 -0700 (PDT) Received: from gerbillo.redhat.com (146-241-225-9.dyn.eolo.it. [146.241.225.9]) by smtp.gmail.com with ESMTPSA id y20-20020aa7d514000000b00537708be5c6sm869929edq.73.2023.10.05.03.39.06 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 05 Oct 2023 03:39:07 -0700 (PDT) Message-ID: <2554ed057e08e66dd110c3e09a27378b9a06bdd6.camel@redhat.com> Subject: Re: [PATCH 3/3] cnic,bnx2,bnx2x: use UIO_MEM_DMA_COHERENT From: Paolo Abeni To: Hannes Reinecke , Greg Kroah-Hartman , Jerry Snitselaar Cc: Christoph Hellwig , Chris Leech , Rasesh Mody , Ariel Elior , Sudarsana Kalluru , Manish Chopra , Nilesh Javali , Manish Rangankar , John Meneghini , Lee Duncan , Mike Christie , Hannes Reinecke , netdev@vger.kernel.org, linux-kernel@vger.kernel.org Date: Thu, 05 Oct 2023 12:39:05 +0200 In-Reply-To: <0e0040be-0375-4461-914d-1ea9d04ee62c@suse.de> References: <20230929170023.1020032-1-cleech@redhat.com> <20230929170023.1020032-4-cleech@redhat.com> <2023093055-gotten-astronomy-a98b@gregkh> <2023093002-unlighted-ragged-c6e1@gregkh> <2023100114-flatware-mourner-3fed@gregkh> <7pq4ptas5wpcxd3v4p7iwvgoj7vrpta6aqfppqmuoccpk4mg5t@fwxm3apjkez3> <20231002060424.GA781@lst.de> <2023100233-salsa-joyous-6d8c@gregkh> <0e0040be-0375-4461-914d-1ea9d04ee62c@suse.de> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.46.4 (3.46.4-1.fc37) Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE, RCVD_IN_MSPIKE_H3,RCVD_IN_MSPIKE_WL,SPF_HELO_NONE,SPF_NONE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net On Mon, 2023-10-02 at 10:59 +0200, Hannes Reinecke wrote: > On 10/2/23 10:46, Greg Kroah-Hartman wrote: > > On Mon, Oct 02, 2023 at 12:50:21AM -0700, Jerry Snitselaar wrote: > > > On Mon, Oct 02, 2023 at 08:04:24AM +0200, Christoph Hellwig wrote: > > > > On Sun, Oct 01, 2023 at 07:22:36AM -0700, Jerry Snitselaar wrote: > > > > > Changes last year to the dma-mapping api to no longer allow __GFP= _COMP, > > > > > in particular these two (from the e529d3507a93 dma-mapping pull f= or > > > > > 6.2): > > > >=20 > > > > That's complete BS. The driver was broken since day 1 and always > > > > ignored the DMA API requirement to never try to grab the page from = the > > > > dma coherent allocation because you generally speaking can't. It j= ust > > > > happened to accidentally work the trivial dma coherent allocator th= at > > > > is used on x86. > > > >=20 > > >=20 > > > re-sending since gmail decided to not send plain text: > > >=20 > > > Yes, I agree that it has been broken and misusing the API. Greg's > > > question was what changed though, and it was the clean up of > > > __GFP_COMP in dma-mapping that brought the problem in the driver to > > > light. > > >=20 > > > I already said the other day that cnic has been doing this for 14 > > > years. I'm not blaming you or your __GFP_COMP cleanup commits, they > > > just uncovered that cnic was doing something wrong. My apologies if > > > you took it that way. > >=20 > > As these devices aren't being made anymore, and this api is really not = a > > good idea in the first place, why don't we just leave it broken and see > > if anyone notices? > >=20 > Guess what triggered this mail thread. > Some customers did notice. >=20 > Problem is that these devices were built as the network interface in=20 > some bladecenter machines, so you can't just replace them with a=20 > different Ethernet card. This route looks a no-go. Out of sheer ignorance, would the iommu hack hinted in the cover letter require similar controversial changes? Cheers, Paolo