* [PATCH v5 0/2] virtio_ring: check desc == NULL when using indirect with packed
@ 2021-10-20 11:05 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
0 siblings, 2 replies; 4+ messages in thread
From: Xuan Zhuo @ 2021-10-20 11:05 UTC (permalink / raw)
To: Michael S. Tsirkin, virtualization; +Cc: David S. Miller, Tiwei Bie
Fix theoretical issues in virtio_ring.
v5:
Update commit message.
v4:
Inside the #2 patch, virtqueue_add_indirect_packed() return -EAGAIN when
desc == NULL.
v3:
Update commit message of the #1 patch.
v2:
Separate the style fix into a single patch.
Xuan Zhuo (2):
virtio_ring: make virtqueue_add_indirect_packed prettier
virtio_ring: check desc == NULL when using indirect with packed
drivers/virtio/virtio_ring.c | 26 +++++++++++++++++---------
1 file changed, 17 insertions(+), 9 deletions(-)
--
2.31.0
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^ permalink raw reply [flat|nested] 4+ messages in thread
* [PATCH v5 1/2] virtio_ring: make virtqueue_add_indirect_packed prettier
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 ` Xuan Zhuo
2021-10-20 11:05 ` [PATCH v5 2/2] virtio_ring: check desc == NULL when using indirect with packed Xuan Zhuo
1 sibling, 0 replies; 4+ messages in thread
From: Xuan Zhuo @ 2021-10-20 11:05 UTC (permalink / raw)
To: Michael S. Tsirkin, virtualization; +Cc: David S. Miller, Tiwei Bie
Align the arguments of virtqueue_add_indirect_packed() to the open ( to
make it look prettier.
Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Acked-by: Jason Wang <jasowang@redhat.com>
---
drivers/virtio/virtio_ring.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)
diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index dd95dfd85e98..91a46c4da87d 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -1050,12 +1050,12 @@ 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[],
+ unsigned int total_sg,
+ unsigned int out_sgs,
+ unsigned int in_sgs,
+ void *data,
+ gfp_t gfp)
{
struct vring_packed_desc *desc;
struct scatterlist *sg;
--
2.31.0
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^ permalink raw reply related [flat|nested] 4+ messages in thread
* [PATCH v5 2/2] virtio_ring: check desc == NULL when using indirect with packed
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 ` Xuan Zhuo
2021-10-20 11:09 ` Michael S. Tsirkin
1 sibling, 1 reply; 4+ messages in thread
From: Xuan Zhuo @ 2021-10-20 11:05 UTC (permalink / raw)
To: Michael S. Tsirkin, virtualization; +Cc: David S. Miller, Tiwei Bie
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");
@@ -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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* Re: [PATCH v5 2/2] virtio_ring: check desc == NULL when using indirect with packed
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
0 siblings, 0 replies; 4+ messages in thread
From: Michael S. Tsirkin @ 2021-10-20 11:09 UTC (permalink / raw)
To: Xuan Zhuo; +Cc: David S. Miller, Tiwei Bie, virtualization
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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