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=-0.8 required=3.0 tests=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 A292FC433E0 for ; Thu, 21 May 2020 08:01:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8C165206B6 for ; Thu, 21 May 2020 08:01:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728473AbgEUIBi convert rfc822-to-8bit (ORCPT ); Thu, 21 May 2020 04:01:38 -0400 Received: from eu-smtp-delivery-151.mimecast.com ([207.82.80.151]:51701 "EHLO eu-smtp-delivery-151.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728129AbgEUIBi (ORCPT ); Thu, 21 May 2020 04:01:38 -0400 Received: from AcuMS.aculab.com (156.67.243.126 [156.67.243.126]) (Using TLS) by relay.mimecast.com with ESMTP id uk-mta-186-4FoxtkRnOIu_oKGM1EEfFg-1; Thu, 21 May 2020 09:01:34 +0100 X-MC-Unique: 4FoxtkRnOIu_oKGM1EEfFg-1 Received: from AcuMS.Aculab.com (fd9f:af1c:a25b:0:43c:695e:880f:8750) by AcuMS.aculab.com (fd9f:af1c:a25b:0:43c:695e:880f:8750) with Microsoft SMTP Server (TLS) id 15.0.1347.2; Thu, 21 May 2020 09:01:33 +0100 Received: from AcuMS.Aculab.com ([fe80::43c:695e:880f:8750]) by AcuMS.aculab.com ([fe80::43c:695e:880f:8750%12]) with mapi id 15.00.1347.000; Thu, 21 May 2020 09:01:33 +0100 From: David Laight To: 'Christoph Hellwig' , "David S. Miller" , Jakub Kicinski CC: Eric Dumazet , Alexey Kuznetsov , Hideaki YOSHIFUJI , "Vlad Yasevich" , Neil Horman , "Marcelo Ricardo Leitner" , Jon Maloy , Ying Xue , "drbd-dev@lists.linbit.com" , "linux-kernel@vger.kernel.org" , "linux-rdma@vger.kernel.org" , "linux-nvme@lists.infradead.org" , "target-devel@vger.kernel.org" , "linux-afs@lists.infradead.org" , "linux-cifs@vger.kernel.org" , "cluster-devel@redhat.com" , "ocfs2-devel@oss.oracle.com" , "netdev@vger.kernel.org" , "linux-sctp@vger.kernel.org" , "ceph-devel@vger.kernel.org" , "rds-devel@oss.oracle.com" , "linux-nfs@vger.kernel.org" Subject: RE: remove kernel_setsockopt and kernel_getsockopt v2 Thread-Topic: remove kernel_setsockopt and kernel_getsockopt v2 Thread-Index: AQHWL0EWFDRlmpM/90uRt9jvD36P/KiyKtMA Date: Thu, 21 May 2020 08:01:33 +0000 Message-ID: <138a17dfff244c089b95f129e4ea2f66@AcuMS.aculab.com> References: <20200520195509.2215098-1-hch@lst.de> In-Reply-To: <20200520195509.2215098-1-hch@lst.de> Accept-Language: en-GB, en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.202.205.107] MIME-Version: 1.0 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: aculab.com Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-rdma-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org From: Christoph Hellwig > Sent: 20 May 2020 20:55 > > this series removes the kernel_setsockopt and kernel_getsockopt > functions, and instead switches their users to small functions that > implement setting (or in one case getting) a sockopt directly using > a normal kernel function call with type safety and all the other > benefits of not having a function call. > > In some cases these functions seem pretty heavy handed as they do > a lock_sock even for just setting a single variable, but this mirrors > the real setsockopt implementation unlike a few drivers that just set > set the fields directly. How much does this increase the kernel code by? You are also replicating a lot of code making it more difficult to maintain. I don't think the performance of an socket option code really matters - it is usually done once when a socket is initialised and the other costs of establishing a connection will dominate. Pulling the user copies outside the [gs]etsocksopt switch statement not only reduces the code size (source and object) and trivially allows kernel_[sg]sockopt() to me added to the list of socket calls. It probably isn't possible to pull the usercopies right out into the syscall wrapper because of some broken requests. I worried about whether getsockopt() should read the entire user buffer first. SCTP needs the some of it often (including a sockaddr_storage in one case), TCP needs it once. However the cost of reading a few words is small, and a big buffer probably needs setting to avoid leaking kernel memory if the structure has holes or fields that don't get set. Reading from userspace solves both issues. David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales) From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Laight Date: Thu, 21 May 2020 08:01:33 +0000 Subject: RE: remove kernel_setsockopt and kernel_getsockopt v2 Message-Id: <138a17dfff244c089b95f129e4ea2f66@AcuMS.aculab.com> List-Id: References: <20200520195509.2215098-1-hch@lst.de> In-Reply-To: <20200520195509.2215098-1-hch@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: 'Christoph Hellwig' , "David S. Miller" , Jakub Kicinski Cc: Eric Dumazet , Alexey Kuznetsov , Hideaki YOSHIFUJI , Vlad Yasevich , Neil Horman , Marcelo Ricardo Leitner , Jon Maloy , Ying Xue , "drbd-dev@lists.linbit.com" , "linux-kernel@vger.kernel.org" , "linux-rdma@vger.kernel.org" , "linux-nvme@lists.infradead.org" , "target-devel@vger.kernel.org" , "linux-afs@lists.infradead.org" , "linux-cifs@vger.kernel.org" , cluster-devel@redhat.co From: Christoph Hellwig > Sent: 20 May 2020 20:55 > > this series removes the kernel_setsockopt and kernel_getsockopt > functions, and instead switches their users to small functions that > implement setting (or in one case getting) a sockopt directly using > a normal kernel function call with type safety and all the other > benefits of not having a function call. > > In some cases these functions seem pretty heavy handed as they do > a lock_sock even for just setting a single variable, but this mirrors > the real setsockopt implementation unlike a few drivers that just set > set the fields directly. How much does this increase the kernel code by? You are also replicating a lot of code making it more difficult to maintain. I don't think the performance of an socket option code really matters - it is usually done once when a socket is initialised and the other costs of establishing a connection will dominate. Pulling the user copies outside the [gs]etsocksopt switch statement not only reduces the code size (source and object) and trivially allows kernel_[sg]sockopt() to me added to the list of socket calls. It probably isn't possible to pull the usercopies right out into the syscall wrapper because of some broken requests. I worried about whether getsockopt() should read the entire user buffer first. SCTP needs the some of it often (including a sockaddr_storage in one case), TCP needs it once. However the cost of reading a few words is small, and a big buffer probably needs setting to avoid leaking kernel memory if the structure has holes or fields that don't get set. Reading from userspace solves both issues. David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales) 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=-0.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED 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 765B4C433E0 for ; Thu, 21 May 2020 08:01:47 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 2E45F206B6 for ; Thu, 21 May 2020 08:01:47 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="nixtHhHq" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2E45F206B6 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=ACULAB.COM Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:In-Reply-To:References: Message-ID:Date:Subject:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=Gm4/ROknXRZsxW2jO9STQwGEkzkjs5ji2+Zqjua+hwg=; b=nixtHhHqfxLjIZ /aFAX4h/M+mSn+fjhS52a0ZPjHFp4bAGQ/BpaCBaVcwmTQVQGmrWKq6cmRItPaKrRzd94uU9D/yUu hEP7Qs0smdDlfa/PmNUir7NBaCr4w2W2IHTgasmu+HEiDBXK4aHt0g+8TEjSv6h/5L7sfjr4isATz bjpx5NYw+p95iNG1VCF0KYsGY/E6hPdtJmbND5qnXGeDC9dq8FqZL2USoXx8xlcD84lUF5GyXB2WL NDsphyePEsS5tBYqG2jG7Ff+CrPVHZIyxMSGw7KqF1Kvelo5Ox4w9wH+4+C9lrg/R925378M05Fyj k3UdImXhWnJx+Xumu3Gw==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1jbg9A-0002n2-EJ; Thu, 21 May 2020 08:01:44 +0000 Received: from eu-smtp-delivery-151.mimecast.com ([207.82.80.151]) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1jbg96-0002kV-Jn for linux-nvme@lists.infradead.org; Thu, 21 May 2020 08:01:42 +0000 Received: from AcuMS.aculab.com (156.67.243.126 [156.67.243.126]) (Using TLS) by relay.mimecast.com with ESMTP id uk-mta-186-4FoxtkRnOIu_oKGM1EEfFg-1; Thu, 21 May 2020 09:01:34 +0100 X-MC-Unique: 4FoxtkRnOIu_oKGM1EEfFg-1 Received: from AcuMS.Aculab.com (fd9f:af1c:a25b:0:43c:695e:880f:8750) by AcuMS.aculab.com (fd9f:af1c:a25b:0:43c:695e:880f:8750) with Microsoft SMTP Server (TLS) id 15.0.1347.2; Thu, 21 May 2020 09:01:33 +0100 Received: from AcuMS.Aculab.com ([fe80::43c:695e:880f:8750]) by AcuMS.aculab.com ([fe80::43c:695e:880f:8750%12]) with mapi id 15.00.1347.000; Thu, 21 May 2020 09:01:33 +0100 From: David Laight To: 'Christoph Hellwig' , "David S. Miller" , Jakub Kicinski Subject: RE: remove kernel_setsockopt and kernel_getsockopt v2 Thread-Topic: remove kernel_setsockopt and kernel_getsockopt v2 Thread-Index: AQHWL0EWFDRlmpM/90uRt9jvD36P/KiyKtMA Date: Thu, 21 May 2020 08:01:33 +0000 Message-ID: <138a17dfff244c089b95f129e4ea2f66@AcuMS.aculab.com> References: <20200520195509.2215098-1-hch@lst.de> In-Reply-To: <20200520195509.2215098-1-hch@lst.de> Accept-Language: en-GB, en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.202.205.107] MIME-Version: 1.0 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: aculab.com X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200521_010140_919961_DC35A505 X-CRM114-Status: GOOD ( 12.58 ) X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Marcelo Ricardo Leitner , Eric Dumazet , "linux-nvme@lists.infradead.org" , "linux-sctp@vger.kernel.org" , "target-devel@vger.kernel.org" , "linux-afs@lists.infradead.org" , "drbd-dev@lists.linbit.com" , "linux-cifs@vger.kernel.org" , "rds-devel@oss.oracle.com" , "linux-rdma@vger.kernel.org" , "cluster-devel@redhat.com" , Alexey Kuznetsov , "ceph-devel@vger.kernel.org" , "linux-nfs@vger.kernel.org" , Neil Horman , Hideaki YOSHIFUJI , "netdev@vger.kernel.org" , Vlad Yasevich , "linux-kernel@vger.kernel.org" , Jon Maloy , Ying Xue , "ocfs2-devel@oss.oracle.com" Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org From: Christoph Hellwig > Sent: 20 May 2020 20:55 > > this series removes the kernel_setsockopt and kernel_getsockopt > functions, and instead switches their users to small functions that > implement setting (or in one case getting) a sockopt directly using > a normal kernel function call with type safety and all the other > benefits of not having a function call. > > In some cases these functions seem pretty heavy handed as they do > a lock_sock even for just setting a single variable, but this mirrors > the real setsockopt implementation unlike a few drivers that just set > set the fields directly. How much does this increase the kernel code by? You are also replicating a lot of code making it more difficult to maintain. I don't think the performance of an socket option code really matters - it is usually done once when a socket is initialised and the other costs of establishing a connection will dominate. Pulling the user copies outside the [gs]etsocksopt switch statement not only reduces the code size (source and object) and trivially allows kernel_[sg]sockopt() to me added to the list of socket calls. It probably isn't possible to pull the usercopies right out into the syscall wrapper because of some broken requests. I worried about whether getsockopt() should read the entire user buffer first. SCTP needs the some of it often (including a sockaddr_storage in one case), TCP needs it once. However the cost of reading a few words is small, and a big buffer probably needs setting to avoid leaking kernel memory if the structure has holes or fields that don't get set. Reading from userspace solves both issues. David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales) _______________________________________________ linux-nvme mailing list linux-nvme@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-nvme From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Laight Date: Thu, 21 May 2020 08:01:33 +0000 Subject: [Ocfs2-devel] remove kernel_setsockopt and kernel_getsockopt v2 In-Reply-To: <20200520195509.2215098-1-hch@lst.de> References: <20200520195509.2215098-1-hch@lst.de> Message-ID: <138a17dfff244c089b95f129e4ea2f66@AcuMS.aculab.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: 'Christoph Hellwig' , "David S. Miller" , Jakub Kicinski Cc: Eric Dumazet , Alexey Kuznetsov , Hideaki YOSHIFUJI , Vlad Yasevich , Neil Horman , Marcelo Ricardo Leitner , Jon Maloy , Ying Xue , "drbd-dev@lists.linbit.com" , "linux-kernel@vger.kernel.org" , "linux-rdma@vger.kernel.org" , "linux-nvme@lists.infradead.org" , "target-devel@vger.kernel.org" , "linux-afs@lists.infradead.org" , "linux-cifs@vger.kernel.org" , cluster-devel@redhat.co From: Christoph Hellwig > Sent: 20 May 2020 20:55 > > this series removes the kernel_setsockopt and kernel_getsockopt > functions, and instead switches their users to small functions that > implement setting (or in one case getting) a sockopt directly using > a normal kernel function call with type safety and all the other > benefits of not having a function call. > > In some cases these functions seem pretty heavy handed as they do > a lock_sock even for just setting a single variable, but this mirrors > the real setsockopt implementation unlike a few drivers that just set > set the fields directly. How much does this increase the kernel code by? You are also replicating a lot of code making it more difficult to maintain. I don't think the performance of an socket option code really matters - it is usually done once when a socket is initialised and the other costs of establishing a connection will dominate. Pulling the user copies outside the [gs]etsocksopt switch statement not only reduces the code size (source and object) and trivially allows kernel_[sg]sockopt() to me added to the list of socket calls. It probably isn't possible to pull the usercopies right out into the syscall wrapper because of some broken requests. I worried about whether getsockopt() should read the entire user buffer first. SCTP needs the some of it often (including a sockaddr_storage in one case), TCP needs it once. However the cost of reading a few words is small, and a big buffer probably needs setting to avoid leaking kernel memory if the structure has holes or fields that don't get set. Reading from userspace solves both issues. David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales) From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Laight Date: Thu, 21 May 2020 08:01:33 +0000 Subject: [Cluster-devel] remove kernel_setsockopt and kernel_getsockopt v2 In-Reply-To: <20200520195509.2215098-1-hch@lst.de> References: <20200520195509.2215098-1-hch@lst.de> Message-ID: <138a17dfff244c089b95f129e4ea2f66@AcuMS.aculab.com> List-Id: To: cluster-devel.redhat.com MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit From: Christoph Hellwig > Sent: 20 May 2020 20:55 > > this series removes the kernel_setsockopt and kernel_getsockopt > functions, and instead switches their users to small functions that > implement setting (or in one case getting) a sockopt directly using > a normal kernel function call with type safety and all the other > benefits of not having a function call. > > In some cases these functions seem pretty heavy handed as they do > a lock_sock even for just setting a single variable, but this mirrors > the real setsockopt implementation unlike a few drivers that just set > set the fields directly. How much does this increase the kernel code by? You are also replicating a lot of code making it more difficult to maintain. I don't think the performance of an socket option code really matters - it is usually done once when a socket is initialised and the other costs of establishing a connection will dominate. Pulling the user copies outside the [gs]etsocksopt switch statement not only reduces the code size (source and object) and trivially allows kernel_[sg]sockopt() to me added to the list of socket calls. It probably isn't possible to pull the usercopies right out into the syscall wrapper because of some broken requests. I worried about whether getsockopt() should read the entire user buffer first. SCTP needs the some of it often (including a sockaddr_storage in one case), TCP needs it once. However the cost of reading a few words is small, and a big buffer probably needs setting to avoid leaking kernel memory if the structure has holes or fields that don't get set. Reading from userspace solves both issues. David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)