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 5CDC6C433E0 for ; Sat, 16 May 2020 15:37:02 +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 2E0DB20727 for ; Sat, 16 May 2020 15:37:02 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="pSl47cq0" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2E0DB20727 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org 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:In-Reply-To:MIME-Version:References: Message-ID:Subject:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=7xAFJTLgVPGKuZl2tmqWgBPlnQvSg0xuE38z2tW4N5Y=; b=pSl47cq0E/pKy4 HG+PK8mH2fzVYWKs4uA7V5ZvzocR3yR04Cq5udl62roXkyPy9LAcNHGW6PdHUou3OqlyyVpQp1j9H yx12xlPTy8eSTlnLJJT9zTYys5iXRsk6gJGf3p5/Orm3L8cW9jrs8I627rcOgYcST/s5VZfltPZlH 0mR+9JuIQPLR9jVYZLQpSjtxtaH19Xp/zARsxVCrvX4YK021TOKDqKJFZwRkM5n0CrnO4RMmQEeKf 6Je+LiFgL1uIdmWCd+Xz1Uq0a/CBuP12pH8qEqrVoOtxr4nNi2rD4AVNnMtjTp0sEf+jyCA5XqHxP G2EoPOa7W1a/rZ6LUiMA==; 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 1jZyrz-00084y-O4; Sat, 16 May 2020 15:36:59 +0000 Received: from willy by bombadil.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1jZyrs-000842-U1; Sat, 16 May 2020 15:36:52 +0000 Date: Sat, 16 May 2020 08:36:52 -0700 From: Matthew Wilcox To: David Laight Subject: Re: [Ocfs2-devel] [PATCH 27/33] sctp: export sctp_setsockopt_bindx Message-ID: <20200516153652.GM16070@bombadil.infradead.org> References: <20200514062820.GC8564@lst.de> <20200513062649.2100053-1-hch@lst.de> <20200513062649.2100053-28-hch@lst.de> <20200513180058.GB2491@localhost.localdomain> <129070.1589556002@warthog.procyon.org.uk> <05d946ae948946158dbfcbc07939b799@AcuMS.aculab.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <05d946ae948946158dbfcbc07939b799@AcuMS.aculab.com> 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" , 'David Howells' , "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" , Christoph Hellwig , "cluster-devel@redhat.com" , Alexey Kuznetsov , "linux-block@vger.kernel.org" , Jakub Kicinski , "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 , "David S. Miller" , "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 On Sat, May 16, 2020 at 03:11:40PM +0000, David Laight wrote: > From: David Howells > > Sent: 15 May 2020 16:20 > > Christoph Hellwig wrote: > > > > > > The advantage on using kernel_setsockopt here is that sctp module will > > > > only be loaded if dlm actually creates a SCTP socket. With this > > > > change, sctp will be loaded on setups that may not be actually using > > > > it. It's a quite big module and might expose the system. > > > > > > True. Not that the intent is to kill kernel space callers of setsockopt, > > > as I plan to remove the set_fs address space override used for it. > > > > For getsockopt, does it make sense to have the core kernel load optval/optlen > > into a buffer before calling the protocol driver? Then the driver need not > > see the userspace pointer at all. > > > > Similar could be done for setsockopt - allocate a buffer of the size requested > > by the user inside the kernel and pass it into the driver, then copy the data > > back afterwards. > > Yes, it also simplifies all the compat code. > And there is a BPF test in setsockopt that also wants to > pass on a kernel buffer. > > I'm willing to sit and write the patch. > Quoting from a post I made later on Friday. > > Basically: > > This patch sequence (to be written) does the following: > > Patch 1: Change __sys_setsockopt() to allocate a kernel buffer, > copy the data into it then call set_fs(KERNEL_DS). > An on-stack buffer (say 64 bytes) will be used for > small transfers. > > Patch 2: The same for __sys_getsockopt(). > > Patch 3: Compat setsockopt. > > Patch 4: Compat getsockopt. > > Patch 5: Remove the user copies from the global socket options code. > > Patches 6 to n-1; Remove the user copies from the per-protocol code. > > Patch n: Remove the set_fs(KERNEL_DS) from the entry points. > > This should be bisectable. I appreciate your dedication to not publishing the source code to your kernel module, but Christoph's patch series is actually better. It's typesafe rather than passing void pointers around. _______________________________________________ linux-nvme mailing list linux-nvme@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-nvme