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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id BEA98C433EF for ; Mon, 27 Sep 2021 03:29:27 +0000 (UTC) Received: from smtp4.osuosl.org (smtp4.osuosl.org [140.211.166.137]) (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 1CC7D60F94 for ; Mon, 27 Sep 2021 03:29:27 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 1CC7D60F94 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.alibaba.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=lists.linux-foundation.org Received: from localhost (localhost [127.0.0.1]) by smtp4.osuosl.org (Postfix) with ESMTP id D6F30405D2; Mon, 27 Sep 2021 03:29:26 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp4.osuosl.org ([127.0.0.1]) by localhost (smtp4.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id iW67IGZ7aYDj; Mon, 27 Sep 2021 03:29:26 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [IPv6:2605:bc80:3010:104::8cd3:938]) by smtp4.osuosl.org (Postfix) with ESMTPS id 5E13D402B5; Mon, 27 Sep 2021 03:29:25 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id 3F893C000F; Mon, 27 Sep 2021 03:29:25 +0000 (UTC) Received: from smtp3.osuosl.org (smtp3.osuosl.org [IPv6:2605:bc80:3010::136]) by lists.linuxfoundation.org (Postfix) with ESMTP id 1A21FC000D for ; Mon, 27 Sep 2021 03:29:24 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp3.osuosl.org (Postfix) with ESMTP id 0356E6063A for ; Mon, 27 Sep 2021 03:29:24 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp3.osuosl.org ([127.0.0.1]) by localhost (smtp3.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id M-vcMK8k6R9R for ; Mon, 27 Sep 2021 03:29:23 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.8.0 Received: from out30-130.freemail.mail.aliyun.com (out30-130.freemail.mail.aliyun.com [115.124.30.130]) by smtp3.osuosl.org (Postfix) with ESMTPS id AC5D3605CB for ; Mon, 27 Sep 2021 03:29:22 +0000 (UTC) X-Alimail-AntiSpam: AC=PASS; BC=-1|-1; BR=01201311R141e4; CH=green; DM=||false|; DS=||; FP=0|-1|-1|-1|0|-1|-1|-1; HT=e01e04407; MF=xuanzhuo@linux.alibaba.com; NM=1; PH=DS; RN=5; SR=0; TI=SMTPD_---0UpgQzEI_1632713359; Received: from localhost(mailfrom:xuanzhuo@linux.alibaba.com fp:SMTPD_---0UpgQzEI_1632713359) by smtp.aliyun-inc.com(127.0.0.1); Mon, 27 Sep 2021 11:29:19 +0800 MIME-Version: 1.0 message-id: <1632713121.4676855-1-xuanzhuo@linux.alibaba.com> subject: Re: [PATCH] virtio_ring: check desc == NULL when packed and indirect date: Mon, 27 Sep 2021 11:25:21 +0800 from: Xuan Zhuo to: Jason Wang in-reply-to: Cc: "Michael S. Tsirkin" , "David S. Miller" , Tiwei Bie , virtualization X-BeenThere: virtualization@lists.linux-foundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Linux virtualization List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: virtualization-bounces@lists.linux-foundation.org Sender: "Virtualization" On Mon, 27 Sep 2021 11:20:16 +0800, Jason Wang wrote: > On Mon, Sep 27, 2021 at 11:06 AM Xuan Zhuo wrote: > > > > In the case of packed, use indirect desc, since desc is allocated by > > kmalloc_array(), we should check whether its return value is NULL. > > > > Fixes: 1ce9e6055fa ("virtio_ring: introduce packed ring support") > > Signed-off-by: Xuan Zhuo > > --- > > drivers/virtio/virtio_ring.c | 27 ++++++++++++++++----------- > > 1 file changed, 16 insertions(+), 11 deletions(-) > > > > diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c > > index dd95dfd85e98..7dd381eae725 100644 > > --- a/drivers/virtio/virtio_ring.c > > +++ b/drivers/virtio/virtio_ring.c > > @@ -1050,21 +1050,20 @@ static struct vring_packed_desc *alloc_indirect_packed(unsigned int total_sg, > > } > > > > static int virtqueue_add_indirect_packed(struct vring_virtqueue *vq, > > - struct scatterlist *sgs[], > > - unsigned int total_sg, > > - unsigned int out_sgs, > > - unsigned int in_sgs, > > - void *data, > > - gfp_t gfp) > > + struct scatterlist *sgs[], > > + struct vring_packed_desc *desc, > > + unsigned int total_sg, > > + unsigned int out_sgs, > > + unsigned int in_sgs, > > + void *data, > > + gfp_t gfp) > > It looks to me the style changes are mixed with bug fix here. I will make a separate patch for the next version. > > > { > > - struct vring_packed_desc *desc; > > struct scatterlist *sg; > > unsigned int i, n, err_idx; > > u16 head, id; > > dma_addr_t addr; > > > > head = vq->packed.next_avail_idx; > > - desc = alloc_indirect_packed(total_sg, gfp); > > > > if (unlikely(vq->vq.num_free < 1)) { > > pr_debug("Can't add buf len 1 - avail = 0\n"); > > @@ -1191,9 +1190,15 @@ static inline int virtqueue_add_packed(struct virtqueue *_vq, > > > > BUG_ON(total_sg == 0); > > > > - if (virtqueue_use_indirect(_vq, total_sg)) > > - return virtqueue_add_indirect_packed(vq, sgs, total_sg, > > - out_sgs, in_sgs, data, gfp); > > + if (virtqueue_use_indirect(_vq, total_sg)) { > > + desc = alloc_indirect_packed(total_sg, gfp); > > + if (desc) { > > + return virtqueue_add_indirect_packed(vq, sgs, desc, > > + total_sg, > > + out_sgs, in_sgs, > > + data, gfp); > > + } > > + } > > Any reason that we can't fix virtqueue_add_indirect_packed()? It can > help to reduce the changeset and ease the backport. The purpose of this is to fall back to not using indirect when alloc_indirect_packed returns NULL. If we check the return value of alloc_indirect_packed() in virtqueue_add_indirect_packed(), then MUST check the error returned by virtqueue_add_indirect_packed() to determine whether to fall back to the mode that does not use indirect. Thanks. > > Thanks > > > > > head = vq->packed.next_avail_idx; > > avail_used_flags = vq->packed.avail_used_flags; > > -- > > 2.31.0 > > > _______________________________________________ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization