Re: [PATCH v7 2/2] virtio_ring: check desc == NULL when using indirect with packed
From: Jason Wang <hidden>
Date: 2021-10-25 02:31:19
On Mon, Oct 25, 2021 at 9:56 AM Xuan Zhuo [off-list ref] wrote:
When using indirect with packed, we don't check for allocation failures.
This patch checks that and fall back on direct.
Fixes: 1ce9e6055fa0 ("virtio_ring: introduce packed ring support")
Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
---Acked-by: Jason Wang <redacted>
quoted hunk ↗ jump to hunk
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..bc92a2faa28f 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 -ENOMEM; if (unlikely(vq->vq.num_free < 1)) { pr_debug("Can't add buf len 1 - avail = 0\n");@@ -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 != -ENOMEM) + 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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