From: "Michael S. Tsirkin" <mst@redhat.com>
To: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Cc: "David S. Miller" <davem@davemloft.net>,
Tiwei Bie <tiwei.bie@intel.com>,
virtualization@lists.linux-foundation.org
Subject: Re: [PATCH v5 2/2] virtio_ring: check desc == NULL when using indirect with packed
Date: Wed, 20 Oct 2021 07:09:04 -0400 [thread overview]
Message-ID: <20211020070838-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <20211020110551.37358-3-xuanzhuo@linux.alibaba.com>
On Wed, Oct 20, 2021 at 07:05:51PM +0800, Xuan Zhuo wrote:
> When using indirect with packed, we don't check for allocation failures.
> This patch checks that and fall back on direct.
>
> Fixes: 1ce9e6055fa ("virtio_ring: introduce packed ring support")
> Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
> ---
> drivers/virtio/virtio_ring.c | 14 +++++++++++---
> 1 file changed, 11 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
> index 91a46c4da87d..552055157b21 100644
> --- a/drivers/virtio/virtio_ring.c
> +++ b/drivers/virtio/virtio_ring.c
> @@ -1065,6 +1065,8 @@ static int virtqueue_add_indirect_packed(struct vring_virtqueue *vq,
>
> head = vq->packed.next_avail_idx;
> desc = alloc_indirect_packed(total_sg, gfp);
> + if (!desc)
> + return -EAGAIN;
>
> if (unlikely(vq->vq.num_free < 1)) {
> pr_debug("Can't add buf len 1 - avail = 0\n");
I still think ENOMEM is better, this way we handle dma map
failures in the same way.
> @@ -1176,6 +1178,7 @@ static inline int virtqueue_add_packed(struct virtqueue *_vq,
> unsigned int i, n, c, descs_used, err_idx;
> __le16 head_flags, flags;
> u16 head, id, prev, curr, avail_used_flags;
> + int err;
>
> START_USE(vq);
>
> @@ -1191,9 +1194,14 @@ 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)) {
> + err = virtqueue_add_indirect_packed(vq, sgs, total_sg, out_sgs,
> + in_sgs, data, gfp);
> + if (err != -EAGAIN)
> + return err;
> +
> + /* fall back on direct */
> + }
>
> head = vq->packed.next_avail_idx;
> avail_used_flags = vq->packed.avail_used_flags;
> --
> 2.31.0
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prev parent reply other threads:[~2021-10-20 11:09 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-20 11:05 [PATCH v5 0/2] virtio_ring: check desc == NULL when using indirect with packed Xuan Zhuo
2021-10-20 11:05 ` [PATCH v5 1/2] virtio_ring: make virtqueue_add_indirect_packed prettier Xuan Zhuo
2021-10-20 11:05 ` [PATCH v5 2/2] virtio_ring: check desc == NULL when using indirect with packed Xuan Zhuo
2021-10-20 11:09 ` Michael S. Tsirkin [this message]
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