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=-6.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,USER_AGENT_GIT 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 D0E06C10F0E for ; Mon, 15 Apr 2019 18:49:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9E5E82073F for ; Mon, 15 Apr 2019 18:49:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1555354152; bh=2H0wK8BjLhOc9eLqs/aANts+Nw5YlAqrgkPWwiVJ0T0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=O5B72RT9rR1/7KIuBfprk/EDnuC3CvivG5WO9RlGzjWxmdvscY4Xx6dH6jKDtTwug UgDSxbUsja7soC9OeUAs1BhWfbNYAlL8BnzZgeXjz22kdwCu4M61MKRbJfaXjPCdBM fj+Mpmu2yDRJq4bCWN4yEBrGQLShySFjkGoHz99E= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729134AbfDOStL (ORCPT ); Mon, 15 Apr 2019 14:49:11 -0400 Received: from mail.kernel.org ([198.145.29.99]:51062 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728455AbfDOSrg (ORCPT ); Mon, 15 Apr 2019 14:47:36 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id A3520218D3; Mon, 15 Apr 2019 18:47:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1555354056; bh=2H0wK8BjLhOc9eLqs/aANts+Nw5YlAqrgkPWwiVJ0T0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=k5pJFEPihOCN91UZ/Zx1ToBmD8c1/MfsXxZYgh6IKRkUF54Uqh+3oxG+xig/jQj51 oxYo3Ayto5UJCauLAnuL1BNR2lIq5LqM0fdFlk6dBOuwKRqp5ERZt6YTTHYrP3Jv+v 24yChCVVrnOdS3TD59tlDO61OZZWEU59VfEG0RFk= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Cornelia Huck , "Michael S. Tsirkin" , Halil Pasic , Jens Freimann Subject: [PATCH 4.9 70/76] virtio: Honour may_reduce_num in vring_create_virtqueue Date: Mon, 15 Apr 2019 20:44:34 +0200 Message-Id: <20190415183728.569186534@linuxfoundation.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190415183707.712011689@linuxfoundation.org> References: <20190415183707.712011689@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Cornelia Huck commit cf94db21905333e610e479688add629397a4b384 upstream. vring_create_virtqueue() allows the caller to specify via the may_reduce_num parameter whether the vring code is allowed to allocate a smaller ring than specified. However, the split ring allocation code tries to allocate a smaller ring on allocation failure regardless of what the caller specified. This may cause trouble for e.g. virtio-pci in legacy mode, which does not support ring resizing. (The packed ring code does not resize in any case.) Let's fix this by bailing out immediately in the split ring code if the requested size cannot be allocated and may_reduce_num has not been specified. While at it, fix a typo in the usage instructions. Fixes: 2a2d1382fe9d ("virtio: Add improved queue allocation API") Cc: stable@vger.kernel.org # v4.6+ Signed-off-by: Cornelia Huck Signed-off-by: Michael S. Tsirkin Reviewed-by: Halil Pasic Reviewed-by: Jens Freimann Signed-off-by: Greg Kroah-Hartman --- drivers/virtio/virtio_ring.c | 2 ++ include/linux/virtio_ring.h | 2 +- 2 files changed, 3 insertions(+), 1 deletion(-) --- a/drivers/virtio/virtio_ring.c +++ b/drivers/virtio/virtio_ring.c @@ -1040,6 +1040,8 @@ struct virtqueue *vring_create_virtqueue GFP_KERNEL|__GFP_NOWARN|__GFP_ZERO); if (queue) break; + if (!may_reduce_num) + return NULL; } if (!num) --- a/include/linux/virtio_ring.h +++ b/include/linux/virtio_ring.h @@ -62,7 +62,7 @@ struct virtqueue; /* * Creates a virtqueue and allocates the descriptor ring. If * may_reduce_num is set, then this may allocate a smaller ring than - * expected. The caller should query virtqueue_get_ring_size to learn + * expected. The caller should query virtqueue_get_vring_size to learn * the actual size of the ring. */ struct virtqueue *vring_create_virtqueue(unsigned int index,