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=-8.3 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 AA9C0C5DF62 for ; Wed, 6 Nov 2019 13:53:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6BA6B214D8 for ; Wed, 6 Nov 2019 13:53:21 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="DxrIuMXt" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731702AbfKFNxU (ORCPT ); Wed, 6 Nov 2019 08:53:20 -0500 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:58138 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726673AbfKFNxT (ORCPT ); Wed, 6 Nov 2019 08:53:19 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1573048398; 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:autocrypt:autocrypt; bh=v+AWAxfDzYP0DMgd1VtOBpTj9iVgFk2qNbX9GR9YwRs=; b=DxrIuMXtdsr0vHg0YqLqQcUihQdxL96fQ3pazf5zZLmwNTI736Xt7v0kNepfeKY2HMawA7 kvLMNrr+pYXxNRUd4V3UYukyTCbT4aWvjX83ukkLOmJ2C2VIaTwGbePQ+LFVU9KSB96se6 HDg1rkpXvSM9/Vna+aD+ju+ANQKDcXY= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-187-hajMUZ2aO_aTyOmBsmPdPg-1; Wed, 06 Nov 2019 08:53:14 -0500 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 976B61005500; Wed, 6 Nov 2019 13:53:13 +0000 (UTC) Received: from [10.36.117.83] (ovpn-117-83.ams2.redhat.com [10.36.117.83]) by smtp.corp.redhat.com (Postfix) with ESMTP id 5CCD060BF4; Wed, 6 Nov 2019 13:53:07 +0000 (UTC) Subject: Re: [PATCH] virtio_console: allocate inbufs in add_port() only if it is needed To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , Amit Shah , virtualization@lists.linux-foundation.org, Arnd Bergmann , "Michael S . Tsirkin" References: <20191018164718.15999-1-lvivier@redhat.com> From: Laurent Vivier Autocrypt: addr=lvivier@redhat.com; prefer-encrypt=mutual; keydata= mQINBFYFJhkBEAC2me7w2+RizYOKZM+vZCx69GTewOwqzHrrHSG07MUAxJ6AY29/+HYf6EY2 WoeuLWDmXE7A3oJoIsRecD6BXHTb0OYS20lS608anr3B0xn5g0BX7es9Mw+hV/pL+63EOCVm SUVTEQwbGQN62guOKnJJJfphbbv82glIC/Ei4Ky8BwZkUuXd7d5NFJKC9/GDrbWdj75cDNQx UZ9XXbXEKY9MHX83Uy7JFoiFDMOVHn55HnncflUncO0zDzY7CxFeQFwYRbsCXOUL9yBtqLer Ky8/yjBskIlNrp0uQSt9LMoMsdSjYLYhvk1StsNPg74+s4u0Q6z45+l8RAsgLw5OLtTa+ePM JyS7OIGNYxAX6eZk1+91a6tnqfyPcMbduxyBaYXn94HUG162BeuyBkbNoIDkB7pCByed1A7q q9/FbuTDwgVGVLYthYSfTtN0Y60OgNkWCMtFwKxRaXt1WFA5ceqinN/XkgA+vf2Ch72zBkJL RBIhfOPFv5f2Hkkj0MvsUXpOWaOjatiu0fpPo6Hw14UEpywke1zN4NKubApQOlNKZZC4hu6/ 8pv2t4HRi7s0K88jQYBRPObjrN5+owtI51xMaYzvPitHQ2053LmgsOdN9EKOqZeHAYG2SmRW LOxYWKX14YkZI5j/TXfKlTpwSMvXho+efN4kgFvFmP6WT+tPnwARAQABtCNMYXVyZW50IFZp dmllciA8bHZpdmllckByZWRoYXQuY29tPokCOAQTAQIAIgUCVgVQgAIbAwYLCQgHAwIGFQgC CQoLBBYCAwECHgECF4AACgkQ8ww4vT8vvjwpgg//fSGy0Rs/t8cPFuzoY1cex4limJQfReLr SJXCANg9NOWy/bFK5wunj+h/RCFxIFhZcyXveurkBwYikDPUrBoBRoOJY/BHK0iZo7/WQkur 6H5losVZtrotmKOGnP/lJYZ3H6OWvXzdz8LL5hb3TvGOP68K8Bn8UsIaZJoeiKhaNR0sOJyI YYbgFQPWMHfVwHD/U+/gqRhD7apVysxv5by/pKDln1I5v0cRRH6hd8M8oXgKhF2+rAOL7gvh jEHSSWKUlMjC7YwwjSZmUkL+TQyE18e2XBk85X8Da3FznrLiHZFHQ/NzETYxRjnOzD7/kOVy gKD/o7asyWQVU65mh/ECrtjfhtCBSYmIIVkopoLaVJ/kEbVJQegT2P6NgERC/31kmTF69vn8 uQyW11Hk8tyubicByL3/XVBrq4jZdJW3cePNJbTNaT0d/bjMg5zCWHbMErUib2Nellnbg6bc 2HLDe0NLVPuRZhHUHM9hO/JNnHfvgiRQDh6loNOUnm9Iw2YiVgZNnT4soUehMZ7au8PwSl4I KYE4ulJ8RRiydN7fES3IZWmOPlyskp1QMQBD/w16o+lEtY6HSFEzsK3o0vuBRBVp2WKnssVH qeeV01ZHw0bvWKjxVNOksP98eJfWLfV9l9e7s6TaAeySKRRubtJ+21PRuYAxKsaueBfUE7ZT 7ze0LUxhdXJlbnQgVml2aWVyIChSZWQgSGF0KSA8bHZpdmllckByZWRoYXQuY29tPokCOAQT AQIAIgUCVgUmGQIbAwYLCQgHAwIGFQgCCQoLBBYCAwECHgECF4AACgkQ8ww4vT8vvjxtNBAA o2xGmbXl9vJQALkj7MVlsMlgewQ1rdoZl+bZ6ythTSBsqwwtl1BUTQGA1GF2LAchRVYca5bJ lw4ai5OdZ/rc5dco2XgrRFtj1np703BzNEhGU1EFxtms/Y9YOobq/GZpck5rK8jV4osEb8oc 3xEgCm/xFwI/2DOe0/s2cHKzRkvdmKWEDhT1M+7UhtSCnloX776zCsrofYiHP2kasFyMa/5R 9J1Rt9Ax/jEAX5vFJ8+NPf68497nBfrAtLM3Xp03YJSr/LDxer44Mevhz8dFw7IMRLhnuSfr 8jP93lr6Wa8zOe3pGmFXZWpNdkV/L0HaeKwTyDKKdUDH4U7SBnE1gcDfe9x08G+oDfVhqED8 qStKCxPYxRUKIdUjGPF3f5oj7N56Q5zZaZkfxeLNTQ13LDt3wGbVHyZxzFc81B+qT8mkm74y RbeVSuviPTYjbBQ66GsUgiZZpDUyJ6s54fWqQdJf4VFwd7M/mS8WEejbSjglGHMxMGiBeRik Y0+ur5KAF7z0D1KfW1kHO9ImQ0FbEbMbTMf9u2+QOCrSWOz/rj23EwPrCQ2TSRI2fWakMJZ+ zQZvy+ei3D7lZ09I9BT/GfFkTIONgtNfDxwyMc4v4XyP0IvvZs/YZqt7j3atyTZM0S2HSaZ9 rXmQYkBt1/u691cZfvy+Tr2xZaDpFcjPkci5Ag0EVgUmGQEQALxSQRbl/QOnmssVDxWhHM5T Gxl7oLNJms2zmBpcmlrIsn8nNz0rRyxT460k2niaTwowSRK8KWVDeAW6ZAaWiYjLlTunoKwv F8vP3JyWpBz0diTxL5o+xpvy/Q6YU3BNefdq8Vy3rFsxgW7mMSrI/CxJ667y8ot5DVugeS2N yHfmZlPGE0Nsy7hlebS4liisXOrN3jFzasKyUws3VXek4V65lHwB23BVzsnFMn/bw/rPliqX Gcwl8CoJu8dSyrCcd1Ibs0/Inq9S9+t0VmWiQWfQkz4rvEeTQkp/VfgZ6z98JRW7S6l6eoph oWs0/ZyRfOm+QVSqRfFZdxdP2PlGeIFMC3fXJgygXJkFPyWkVElr76JTbtSHsGWbt6xUlYHK XWo+xf9WgtLeby3cfSkEchACrxDrQpj+Jt/JFP+q997dybkyZ5IoHWuPkn7uZGBrKIHmBunT co1+cKSuRiSCYpBIXZMHCzPgVDjk4viPbrV9NwRkmaOxVvye0vctJeWvJ6KA7NoAURplIGCq kCRwg0MmLrfoZnK/gRqVJ/f6adhU1oo6z4p2/z3PemA0C0ANatgHgBb90cd16AUxpdEQmOCm dNnNJF/3Zt3inzF+NFzHoM5Vwq6rc1JPjfC3oqRLJzqAEHBDjQFlqNR3IFCIAo4SYQRBdAHB CzkM4rWyRhuVABEBAAGJAh8EGAECAAkFAlYFJhkCGwwACgkQ8ww4vT8vvjwg9w//VQrcnVg3 TsjEybxDEUBm8dBmnKqcnTBFmxN5FFtIWlEuY8+YMiWRykd8Ln9RJ/98/ghABHz9TN8TRo2b 6WimV64FmlVn17Ri6FgFU3xNt9TTEChqAcNg88eYryKsYpFwegGpwUlaUaaGh1m9OrTzcQy+ klVfZWaVJ9Nw0keoGRGb8j4XjVpL8+2xOhXKrM1fzzb8JtAuSbuzZSQPDwQEI5CKKxp7zf76 J21YeRrEW4WDznPyVcDTa+tz++q2S/BpP4W98bXCBIuQgs2m+OflERv5c3Ojldp04/S4NEjX EYRWdiCxN7ca5iPml5gLtuvhJMSy36glU6IW9kn30IWuSoBpTkgV7rLUEhh9Ms82VWW/h2Tx L8enfx40PrfbDtWwqRID3WY8jLrjKfTdR3LW8BnUDNkG+c4FzvvGUs8AvuqxxyHbXAfDx9o/ jXfPHVRmJVhSmd+hC3mcQ+4iX5bBPBPMoDqSoLt5w9GoQQ6gDVP2ZjTWqwSRMLzNr37rJjZ1 pt0DCMMTbiYIUcrhX8eveCJtY7NGWNyxFCRkhxRuGcpwPmRVDwOl39MB3iTsRighiMnijkbL XiKoJ5CDVvX5yicNqYJPKh5MFXN1bvsBkmYiStMRbrD0HoY1kx5/VozBtc70OU0EB8Wrv9hZ D+Ofp0T3KOr1RUHvCZoLURfFhSQ= Message-ID: Date: Wed, 6 Nov 2019 14:53:06 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.1.1 MIME-Version: 1.0 In-Reply-To: <20191018164718.15999-1-lvivier@redhat.com> Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-MC-Unique: hajMUZ2aO_aTyOmBsmPdPg-1 X-Mimecast-Spam-Score: 0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Any comments? Thanks, Laurent On 18/10/2019 18:47, Laurent Vivier wrote: > When we hot unplug a virtserialport and then try to hot plug again, > it fails: >=20 > (qemu) chardev-add socket,id=3Dserial0,path=3D/tmp/serial0,server,nowait > (qemu) device_add virtserialport,bus=3Dvirtio-serial0.0,nr=3D2,\ > chardev=3Dserial0,id=3Dserial0,name=3Dserial0 > (qemu) device_del serial0 > (qemu) device_add virtserialport,bus=3Dvirtio-serial0.0,nr=3D2,\ > chardev=3Dserial0,id=3Dserial0,name=3Dserial0 > kernel error: > virtio-ports vport2p2: Error allocating inbufs > qemu error: > virtio-serial-bus: Guest failure in adding port 2 for device \ > virtio-serial0.0 >=20 > This happens because buffers for the in_vq are allocated when the port is > added but are not released when the port is unplugged. >=20 > They are only released when virtconsole is removed (see a7a69ec0d8e4) >=20 > To avoid the problem and to be symmetric, we could allocate all the buffe= rs > in init_vqs() as they are released in remove_vqs(), but it sounds like > a waste of memory. >=20 > Rather than that, this patch changes add_port() logic to only allocate th= e > buffers if the in_vq has available free slots. >=20 > Fixes: a7a69ec0d8e4 ("virtio_console: free buffers after reset") > Cc: mst@redhat.com > Signed-off-by: Laurent Vivier > --- > drivers/char/virtio_console.c | 17 +++++++++++------ > 1 file changed, 11 insertions(+), 6 deletions(-) >=20 > diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.= c > index 7270e7b69262..77105166fe01 100644 > --- a/drivers/char/virtio_console.c > +++ b/drivers/char/virtio_console.c > @@ -1421,12 +1421,17 @@ static int add_port(struct ports_device *portdev,= u32 id) > =09spin_lock_init(&port->outvq_lock); > =09init_waitqueue_head(&port->waitqueue); > =20 > -=09/* Fill the in_vq with buffers so the host can send us data. */ > -=09nr_added_bufs =3D fill_queue(port->in_vq, &port->inbuf_lock); > -=09if (!nr_added_bufs) { > -=09=09dev_err(port->dev, "Error allocating inbufs\n"); > -=09=09err =3D -ENOMEM; > -=09=09goto free_device; > +=09/* if the in_vq has not already been filled (the port has already bee= n > +=09 * used and unplugged), fill the in_vq with buffers so the host can > +=09 * send us data. > +=09 */ > +=09if (port->in_vq->num_free !=3D 0) { > +=09=09nr_added_bufs =3D fill_queue(port->in_vq, &port->inbuf_lock); > +=09=09if (!nr_added_bufs) { > +=09=09=09dev_err(port->dev, "Error allocating inbufs\n"); > +=09=09=09err =3D -ENOMEM; > +=09=09=09goto free_device; > +=09=09} > =09} > =20 > =09if (is_rproc_serial(port->portdev->vdev)) >=20