Michael S. Tsirkin
2021-Oct-19 13:21 UTC
[PATCH v4 2/2] virtio_ring: check desc == NULL when using indirect with packed
On Tue, Oct 19, 2021 at 07:52:35PM +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 at linux.alibaba.com> > --- > drivers/virtio/virtio_ring.c | 13 ++++++++++--- > 1 file changed, 10 insertions(+), 3 deletions(-) > > diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c > index 91a46c4da87d..44a03b6e4dc4 100644 > --- a/drivers/virtio/virtio_ring.c > +++ b/drivers/virtio/virtio_ring.c > @@ -1065,6 +1065,9 @@ 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) > + /* fall back on direct */this comment belongs in virtqueue_add_packed right after return.> + return -EAGAIN; >-ENOMEM surely?> if (unlikely(vq->vq.num_free < 1)) { > pr_debug("Can't add buf len 1 - avail = 0\n"); > @@ -1176,6 +1179,7 @@ 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 +1195,12 @@ 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; > + } > > head = vq->packed.next_avail_idx; > avail_used_flags = vq->packed.avail_used_flags; > -- > 2.31.0
Xuan Zhuo
2021-Oct-20 02:19 UTC
[PATCH v4 2/2] virtio_ring: check desc == NULL when using indirect with packed
On Tue, 19 Oct 2021 09:21:51 -0400, Michael S. Tsirkin <mst at redhat.com> wrote:> On Tue, Oct 19, 2021 at 07:52:35PM +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 at linux.alibaba.com> > > --- > > drivers/virtio/virtio_ring.c | 13 ++++++++++--- > > 1 file changed, 10 insertions(+), 3 deletions(-) > > > > diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c > > index 91a46c4da87d..44a03b6e4dc4 100644 > > --- a/drivers/virtio/virtio_ring.c > > +++ b/drivers/virtio/virtio_ring.c > > @@ -1065,6 +1065,9 @@ 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) > > + /* fall back on direct */ > > this comment belongs in virtqueue_add_packed right after > return. > > > + return -EAGAIN; > > > > -ENOMEM surely?virtqueue_add_indirect_packed() will return -ENOMEM when dma mmap fails, so we have to choose a different error code. Thanks.> > > if (unlikely(vq->vq.num_free < 1)) { > > pr_debug("Can't add buf len 1 - avail = 0\n"); > > @@ -1176,6 +1179,7 @@ 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 +1195,12 @@ 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; > > + } > > > > head = vq->packed.next_avail_idx; > > avail_used_flags = vq->packed.avail_used_flags; > > -- > > 2.31.0 >