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=-15.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 0A468C433EF for ; Fri, 17 Sep 2021 12:02:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E682D610C8 for ; Fri, 17 Sep 2021 12:02:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243178AbhIQMDe (ORCPT ); Fri, 17 Sep 2021 08:03:34 -0400 Received: from kylie.crudebyte.com ([5.189.157.229]:43545 "EHLO kylie.crudebyte.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242369AbhIQMDa (ORCPT ); Fri, 17 Sep 2021 08:03:30 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=crudebyte.com; s=kylie; h=Content-Type:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From: Content-ID:Content-Description; bh=mwDQ7yL65mWjimIO8xuhY5v9/PdKRAR76I1LgT/xIJw=; b=qoUwGluFKe+XVtLgZIF3PxKGI9 oGLtzS3umUMVjRMoQkSplxFOxgCZ9XmD5WfergkZF6C9kjoHaghNQrutdYHU2dbkvenJKbPLFPYM0 RPPeywCmdmTaR0IHTSa4ctWaALVo/Q5VrraUVDirI28OEhZDJ4yCiwuxC/MH8Zbm8aSXqPoVg373/ h1YVuK7NIQPR7ubAj/6Kt9IMGFAoqK9HIr8OvQXS+xhx99HDtCc97WLO7OJd7frPEbXgY2SBVNmNr VTc2y3B4WCdl6+svCPwJWrmpDlsg23qZ/NjHtmRGvP+gpIRFXQwueBT8Yam1oMVi7jP2UCamoArHO bVAGvHyDKzT9rdSZi7GYGFKh3KI4Mzx8xsFoubE3gaCIEIckbUGnjuvHkgfZKh7nag8Mw2TzoQEKI JzYe893yIimytwy4Q7W4ntqax26xoI1xLiS/hC06Cm+bLBK9ZU0nhRZ7lgMS4f86aPhYNbZNxP2lO pZZaFlT9qhbeXqpi1sy9/toFKrS+86sb6uS4xJYX+kKMguHw0lCdJQq06NKXJGJ/61oHBXZeDus4O Bl19z3E4TYP5oGXJOeObBOobKaqoxs0/i0gX7I131L5uAq+H1GAunpqmDJ3u/4T3pFHixPjkliin+ 8Zv9WebbrCDEHZQ7lk6WrdMz2SYuh6esq0DYZmMzI=; From: Christian Schoenebeck To: v9fs-developer@lists.sourceforge.net Cc: netdev@vger.kernel.org, Dominique Martinet , Eric Van Hensbergen , Latchesar Ionkov , Greg Kurz , Vivek Goyal Subject: Re: [PATCH 6/7] 9p/trans_virtio: support larger msize values Date: Fri, 17 Sep 2021 14:02:04 +0200 Message-ID: <42945636.VKLsUkgjGN@silver> In-Reply-To: <810050b76b9b04f045e3d21b0082358ea3f21391.1631816768.git.linux_oss@crudebyte.com> References: <810050b76b9b04f045e3d21b0082358ea3f21391.1631816768.git.linux_oss@crudebyte.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Donnerstag, 16. September 2021 20:25:16 CEST Christian Schoenebeck wrote: > The virtio transport supports by default a 9p 'msize' of up to > approximately 500 kB. This patches adds support for larger 'msize' > values by resizing the amount of scatter/gather lists if required. > > Signed-off-by: Christian Schoenebeck > --- s/patches/patch/ > net/9p/trans_virtio.c | 52 +++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 52 insertions(+) > > diff --git a/net/9p/trans_virtio.c b/net/9p/trans_virtio.c > index 1a45e0df2336..1f9a0283d7b8 100644 > --- a/net/9p/trans_virtio.c > +++ b/net/9p/trans_virtio.c > @@ -195,6 +195,30 @@ static struct virtqueue_sg *vq_sg_alloc(unsigned int > nsgl) return vq_sg; > } > > +/** > + * Resize passed virtqueue scatter/gather lists to the passed amount of > + * list blocks. > + * @_vq_sg: scatter/gather lists to be resized > + * @nsgl: new amount of scatter/gather list blocks > + */ > +static int vq_sg_resize(struct virtqueue_sg **_vq_sg, unsigned int nsgl) > +{ > + struct virtqueue_sg *vq_sg; > + > + BUG_ON(!_vq_sg || !nsgl); > + vq_sg = *_vq_sg; > + if (vq_sg->nsgl == nsgl) > + return 0; > + > + /* lazy resize implementation for now */ > + vq_sg = vq_sg_alloc(nsgl); > + if (!vq_sg) > + return -ENOMEM; > + Missing kfree(*_vq_sg); here, and probably also a prior memcpy() as in patch 7, i.e.: /* copy over old scatter gather lists */ sz = sizeof(struct virtqueue_sg) + (*_vq_sg)->nsgl * sizeof(struct scatterlist *); memcpy(vq_sg, *_vq_sg, sz); > + *_vq_sg = vq_sg; > + return 0; > +} > + > /** > * p9_virtio_close - reclaim resources of a channel > * @client: client instance > @@ -766,6 +790,10 @@ p9_virtio_create(struct p9_client *client, const char > *devname, char *args) struct virtio_chan *chan; > int ret = -ENOENT; > int found = 0; > +#if !defined(CONFIG_ARCH_NO_SG_CHAIN) > + size_t npages; > + size_t nsgl; > +#endif > > if (devname == NULL) > return -EINVAL; > @@ -788,6 +816,30 @@ p9_virtio_create(struct p9_client *client, const char > *devname, char *args) return ret; > } > > + /* > + * if user supplied an 'msize' option that's larger than what this > + * transport supports by default, then try to allocate more sg lists > + */ > + if (client->msize > client->trans_maxsize) { > +#if !defined(CONFIG_ARCH_NO_SG_CHAIN) > + npages = DIV_ROUND_UP(client->msize, PAGE_SIZE); > + if (npages > chan->p9_max_pages) > + npages = chan->p9_max_pages; > + nsgl = DIV_ROUND_UP(npages, SG_USER_PAGES_PER_LIST); > + if (nsgl > chan->vq_sg->nsgl) { > + /* > + * if resize fails, no big deal, then just > + * continue with default msize instead > + */ > + if (!vq_sg_resize(&chan->vq_sg, nsgl)) { > + client->trans_maxsize = > + PAGE_SIZE * > + ((nsgl * SG_USER_PAGES_PER_LIST) - 3); > + } > + } > +#endif /* !defined(CONFIG_ARCH_NO_SG_CHAIN) */ > + } Probably an error/info message for architectures not supporting SG chains would be useful here, to let users on those system know why they cannot get beyond 500k msize. > + > client->trans = (void *)chan; > client->status = Connected; > chan->client = client;