For non-linear skb use its pages from fragment array as buffers in
virtio tx queue. These pages are already pinned by 'get_user_pages()'
during such skb creation.
Signed-off-by: Arseniy Krasnov <[email protected]>
---
net/vmw_vsock/virtio_transport.c | 37 ++++++++++++++++++++++++++------
1 file changed, 31 insertions(+), 6 deletions(-)
diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c
index e95df847176b..6053d8341091 100644
--- a/net/vmw_vsock/virtio_transport.c
+++ b/net/vmw_vsock/virtio_transport.c
@@ -100,7 +100,9 @@ virtio_transport_send_pkt_work(struct work_struct *work)
vq = vsock->vqs[VSOCK_VQ_TX];
for (;;) {
- struct scatterlist hdr, buf, *sgs[2];
+ /* +1 is for packet header. */
+ struct scatterlist *sgs[MAX_SKB_FRAGS + 1];
+ struct scatterlist bufs[MAX_SKB_FRAGS + 1];
int ret, in_sg = 0, out_sg = 0;
struct sk_buff *skb;
bool reply;
@@ -111,12 +113,35 @@ virtio_transport_send_pkt_work(struct work_struct *work)
virtio_transport_deliver_tap_pkt(skb);
reply = virtio_vsock_skb_reply(skb);
+ sg_init_one(&bufs[0], virtio_vsock_hdr(skb), sizeof(*virtio_vsock_hdr(skb)));
+ sgs[out_sg++] = &bufs[0];
+
+ if (skb_is_nonlinear(skb)) {
+ struct skb_shared_info *si;
+ int i;
+
+ si = skb_shinfo(skb);
+
+ for (i = 0; i < si->nr_frags; i++) {
+ skb_frag_t *skb_frag = &si->frags[i];
+ void *va = page_to_virt(skb_frag->bv_page);
+
+ /* We will use 'page_to_virt()' for userspace page here,
+ * because virtio layer will call 'virt_to_phys()' later
+ * to fill buffer descriptor. We don't touch memory at
+ * "virtual" address of this page.
+ */
+ sg_init_one(&bufs[i + 1],
+ va + skb_frag->bv_offset,
+ skb_frag->bv_len);
+ sgs[out_sg++] = &bufs[i + 1];
+ }
+ } else {
+ if (skb->len > 0) {
+ sg_init_one(&bufs[1], skb->data, skb->len);
+ sgs[out_sg++] = &bufs[1];
+ }
- sg_init_one(&hdr, virtio_vsock_hdr(skb), sizeof(*virtio_vsock_hdr(skb)));
- sgs[out_sg++] = &hdr;
- if (skb->len > 0) {
- sg_init_one(&buf, skb->data, skb->len);
- sgs[out_sg++] = &buf;
}
ret = virtqueue_add_sgs(vq, sgs, out_sg, in_sg, skb, GFP_KERNEL);
--
2.25.1
On Sat, Jun 03, 2023 at 11:49:25PM +0300, Arseniy Krasnov wrote:
> For non-linear skb use its pages from fragment array as buffers in
> virtio tx queue. These pages are already pinned by 'get_user_pages()'
> during such skb creation.
>
> Signed-off-by: Arseniy Krasnov <[email protected]>
> ---
> net/vmw_vsock/virtio_transport.c | 37 ++++++++++++++++++++++++++------
> 1 file changed, 31 insertions(+), 6 deletions(-)
>
> diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c
> index e95df847176b..6053d8341091 100644
> --- a/net/vmw_vsock/virtio_transport.c
> +++ b/net/vmw_vsock/virtio_transport.c
> @@ -100,7 +100,9 @@ virtio_transport_send_pkt_work(struct work_struct *work)
> vq = vsock->vqs[VSOCK_VQ_TX];
>
> for (;;) {
> - struct scatterlist hdr, buf, *sgs[2];
> + /* +1 is for packet header. */
> + struct scatterlist *sgs[MAX_SKB_FRAGS + 1];
> + struct scatterlist bufs[MAX_SKB_FRAGS + 1];
> int ret, in_sg = 0, out_sg = 0;
> struct sk_buff *skb;
> bool reply;
> @@ -111,12 +113,35 @@ virtio_transport_send_pkt_work(struct work_struct *work)
>
> virtio_transport_deliver_tap_pkt(skb);
> reply = virtio_vsock_skb_reply(skb);
> + sg_init_one(&bufs[0], virtio_vsock_hdr(skb), sizeof(*virtio_vsock_hdr(skb)));
> + sgs[out_sg++] = &bufs[0];
> +
> + if (skb_is_nonlinear(skb)) {
> + struct skb_shared_info *si;
> + int i;
> +
> + si = skb_shinfo(skb);
> +
> + for (i = 0; i < si->nr_frags; i++) {
> + skb_frag_t *skb_frag = &si->frags[i];
> + void *va = page_to_virt(skb_frag->bv_page);
> +
> + /* We will use 'page_to_virt()' for userspace page here,
> + * because virtio layer will call 'virt_to_phys()' later
> + * to fill buffer descriptor. We don't touch memory at
> + * "virtual" address of this page.
> + */
> + sg_init_one(&bufs[i + 1],
> + va + skb_frag->bv_offset,
> + skb_frag->bv_len);
> + sgs[out_sg++] = &bufs[i + 1];
> + }
> + } else {
> + if (skb->len > 0) {
> + sg_init_one(&bufs[1], skb->data, skb->len);
> + sgs[out_sg++] = &bufs[1];
> + }
>
> - sg_init_one(&hdr, virtio_vsock_hdr(skb), sizeof(*virtio_vsock_hdr(skb)));
> - sgs[out_sg++] = &hdr;
> - if (skb->len > 0) {
> - sg_init_one(&buf, skb->data, skb->len);
> - sgs[out_sg++] = &buf;
> }
>
> ret = virtqueue_add_sgs(vq, sgs, out_sg, in_sg, skb, GFP_KERNEL);
> --
> 2.25.1
>
LGTM.
Reviewed-by: Bobby Eshleman <[email protected]>
On Sat, Jun 03, 2023 at 11:49:25PM +0300, Arseniy Krasnov wrote:
>For non-linear skb use its pages from fragment array as buffers in
>virtio tx queue. These pages are already pinned by 'get_user_pages()'
>during such skb creation.
>
>Signed-off-by: Arseniy Krasnov <[email protected]>
>---
> net/vmw_vsock/virtio_transport.c | 37 ++++++++++++++++++++++++++------
> 1 file changed, 31 insertions(+), 6 deletions(-)
>
>diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c
>index e95df847176b..6053d8341091 100644
>--- a/net/vmw_vsock/virtio_transport.c
>+++ b/net/vmw_vsock/virtio_transport.c
>@@ -100,7 +100,9 @@ virtio_transport_send_pkt_work(struct work_struct *work)
> vq = vsock->vqs[VSOCK_VQ_TX];
>
> for (;;) {
>- struct scatterlist hdr, buf, *sgs[2];
>+ /* +1 is for packet header. */
>+ struct scatterlist *sgs[MAX_SKB_FRAGS + 1];
>+ struct scatterlist bufs[MAX_SKB_FRAGS + 1];
> int ret, in_sg = 0, out_sg = 0;
> struct sk_buff *skb;
> bool reply;
>@@ -111,12 +113,35 @@ virtio_transport_send_pkt_work(struct work_struct *work)
>
> virtio_transport_deliver_tap_pkt(skb);
> reply = virtio_vsock_skb_reply(skb);
>+ sg_init_one(&bufs[0], virtio_vsock_hdr(skb), sizeof(*virtio_vsock_hdr(skb)));
>+ sgs[out_sg++] = &bufs[0];
Can we use out_sg also to index bufs (here and in the rest of the code)?
E.g.
sg_init_one(&bufs[out_sg], ...)
sgs[out_sg] = &bufs[out_sg];
++out_sg;
...
if (skb->len > 0) {
sg_init_one(&bufs[out_sg], skb->data, skb->len);
sgs[out_sg] = &bufs[out_sg];
++out_sg;
}
etc...
>+
For readability, I would move the smaller branch above:
if (!skb_is_nonlinear(skb)) {
// small block
...
} else {
// big block
...
}
>+ if (skb_is_nonlinear(skb)) {
>+ struct skb_shared_info *si;
>+ int i;
>+
>+ si = skb_shinfo(skb);
>+
>+ for (i = 0; i < si->nr_frags; i++) {
>+ skb_frag_t *skb_frag = &si->frags[i];
>+ void *va = page_to_virt(skb_frag->bv_page);
>+
>+ /* We will use 'page_to_virt()' for userspace page here,
>+ * because virtio layer will call 'virt_to_phys()' later
>+ * to fill buffer descriptor. We don't touch memory at
>+ * "virtual" address of this page.
>+ */
>+ sg_init_one(&bufs[i + 1],
>+ va + skb_frag->bv_offset,
>+ skb_frag->bv_len);
>+ sgs[out_sg++] = &bufs[i + 1];
>+ }
>+ } else {
>+ if (skb->len > 0) {
Should we do the same check (skb->len > 0) for nonlinear skb as well?
Or do the nonlinear ones necessarily have len > 0?
>+ sg_init_one(&bufs[1], skb->data, skb->len);
>+ sgs[out_sg++] = &bufs[1];
>+ }
>
^
Blank line that we can remove.
Stefano
>- sg_init_one(&hdr, virtio_vsock_hdr(skb), sizeof(*virtio_vsock_hdr(skb)));
>- sgs[out_sg++] = &hdr;
>- if (skb->len > 0) {
>- sg_init_one(&buf, skb->data, skb->len);
>- sgs[out_sg++] = &buf;
> }
>
> ret = virtqueue_add_sgs(vq, sgs, out_sg, in_sg, skb, GFP_KERNEL);
>--
>2.25.1
>
On 26.06.2023 18:36, Stefano Garzarella wrote:
> On Sat, Jun 03, 2023 at 11:49:25PM +0300, Arseniy Krasnov wrote:
>> For non-linear skb use its pages from fragment array as buffers in
>> virtio tx queue. These pages are already pinned by 'get_user_pages()'
>> during such skb creation.
>>
>> Signed-off-by: Arseniy Krasnov <[email protected]>
>> ---
>> net/vmw_vsock/virtio_transport.c | 37 ++++++++++++++++++++++++++------
>> 1 file changed, 31 insertions(+), 6 deletions(-)
>>
>> diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c
>> index e95df847176b..6053d8341091 100644
>> --- a/net/vmw_vsock/virtio_transport.c
>> +++ b/net/vmw_vsock/virtio_transport.c
>> @@ -100,7 +100,9 @@ virtio_transport_send_pkt_work(struct work_struct *work)
>> vq = vsock->vqs[VSOCK_VQ_TX];
>>
>> for (;;) {
>> - struct scatterlist hdr, buf, *sgs[2];
>> + /* +1 is for packet header. */
>> + struct scatterlist *sgs[MAX_SKB_FRAGS + 1];
>> + struct scatterlist bufs[MAX_SKB_FRAGS + 1];
>> int ret, in_sg = 0, out_sg = 0;
>> struct sk_buff *skb;
>> bool reply;
>> @@ -111,12 +113,35 @@ virtio_transport_send_pkt_work(struct work_struct *work)
>>
>> virtio_transport_deliver_tap_pkt(skb);
>> reply = virtio_vsock_skb_reply(skb);
>> + sg_init_one(&bufs[0], virtio_vsock_hdr(skb), sizeof(*virtio_vsock_hdr(skb)));
>> + sgs[out_sg++] = &bufs[0];
>
> Can we use out_sg also to index bufs (here and in the rest of the code)?
>
> E.g.
>
> sg_init_one(&bufs[out_sg], ...)
> sgs[out_sg] = &bufs[out_sg];
> ++out_sg;
>
> ...
> if (skb->len > 0) {
> sg_init_one(&bufs[out_sg], skb->data, skb->len);
> sgs[out_sg] = &bufs[out_sg];
> ++out_sg;
> }
>
> etc...
>
>> +
>
> For readability, I would move the smaller branch above:
>
> if (!skb_is_nonlinear(skb)) {
> // small block
> ...
> } else {
> // big block
> ...
> }
>
>> + if (skb_is_nonlinear(skb)) {
>> + struct skb_shared_info *si;
>> + int i;
>> +
>> + si = skb_shinfo(skb);
>> +
>> + for (i = 0; i < si->nr_frags; i++) {
>> + skb_frag_t *skb_frag = &si->frags[i];
>> + void *va = page_to_virt(skb_frag->bv_page);
>> +
>> + /* We will use 'page_to_virt()' for userspace page here,
>> + * because virtio layer will call 'virt_to_phys()' later
>> + * to fill buffer descriptor. We don't touch memory at
>> + * "virtual" address of this page.
>> + */
>> + sg_init_one(&bufs[i + 1],
>> + va + skb_frag->bv_offset,
>> + skb_frag->bv_len);
>> + sgs[out_sg++] = &bufs[i + 1];
>> + }
>> + } else {
>> + if (skb->len > 0) {
>
> Should we do the same check (skb->len > 0) for nonlinear skb as well?
> Or do the nonlinear ones necessarily have len > 0?
Yes, non-linear skb always has 'data_len' > 0, e.g. such skbs always have some
data in it.
Thanks, Arseniy
>
>> + sg_init_one(&bufs[1], skb->data, skb->len);
>> + sgs[out_sg++] = &bufs[1];
>> + }
>>
> ^
> Blank line that we can remove.
>
> Stefano
>
>> - sg_init_one(&hdr, virtio_vsock_hdr(skb), sizeof(*virtio_vsock_hdr(skb)));
>> - sgs[out_sg++] = &hdr;
>> - if (skb->len > 0) {
>> - sg_init_one(&buf, skb->data, skb->len);
>> - sgs[out_sg++] = &buf;
>> }
>>
>> ret = virtqueue_add_sgs(vq, sgs, out_sg, in_sg, skb, GFP_KERNEL);
>> --
>> 2.25.1
>>
>
On Tue, Jun 27, 2023 at 07:39:41AM +0300, Arseniy Krasnov wrote:
>
>
>On 26.06.2023 18:36, Stefano Garzarella wrote:
>> On Sat, Jun 03, 2023 at 11:49:25PM +0300, Arseniy Krasnov wrote:
>>> For non-linear skb use its pages from fragment array as buffers in
>>> virtio tx queue. These pages are already pinned by 'get_user_pages()'
>>> during such skb creation.
>>>
>>> Signed-off-by: Arseniy Krasnov <[email protected]>
>>> ---
>>> net/vmw_vsock/virtio_transport.c | 37 ++++++++++++++++++++++++++------
>>> 1 file changed, 31 insertions(+), 6 deletions(-)
>>>
>>> diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c
>>> index e95df847176b..6053d8341091 100644
>>> --- a/net/vmw_vsock/virtio_transport.c
>>> +++ b/net/vmw_vsock/virtio_transport.c
>>> @@ -100,7 +100,9 @@ virtio_transport_send_pkt_work(struct work_struct *work)
>>> ????vq = vsock->vqs[VSOCK_VQ_TX];
>>>
>>> ????for (;;) {
>>> -??????? struct scatterlist hdr, buf, *sgs[2];
>>> +??????? /* +1 is for packet header. */
>>> +??????? struct scatterlist *sgs[MAX_SKB_FRAGS + 1];
>>> +??????? struct scatterlist bufs[MAX_SKB_FRAGS + 1];
>>> ??????? int ret, in_sg = 0, out_sg = 0;
>>> ??????? struct sk_buff *skb;
>>> ??????? bool reply;
>>> @@ -111,12 +113,35 @@ virtio_transport_send_pkt_work(struct work_struct *work)
>>>
>>> ??????? virtio_transport_deliver_tap_pkt(skb);
>>> ??????? reply = virtio_vsock_skb_reply(skb);
>>> +??????? sg_init_one(&bufs[0], virtio_vsock_hdr(skb), sizeof(*virtio_vsock_hdr(skb)));
>>> +??????? sgs[out_sg++] = &bufs[0];
>>
>> Can we use out_sg also to index bufs (here and in the rest of the code)?
>>
>> E.g.
>>
>> ??????? sg_init_one(&bufs[out_sg], ...)
>> ??????? sgs[out_sg] = &bufs[out_sg];
>> ??????? ++out_sg;
>>
>> ??????? ...
>> ??????????? if (skb->len > 0) {
>> ??????????????? sg_init_one(&bufs[out_sg], skb->data, skb->len);
>> ??????????????? sgs[out_sg] = &bufs[out_sg];
>> ??????????????? ++out_sg;
>> ??????????? }
>>
>> ??????? etc...
>>
>>> +
>>
>> For readability, I would move the smaller branch above:
>>
>> ??????? if (!skb_is_nonlinear(skb)) {
>> ??????????? // small block
>> ??????????? ...
>> ??????? } else {
>> ??????????? // big block
>> ??????????? ...
>> ??????? }
>>
>>> +??????? if (skb_is_nonlinear(skb)) {
>>> +??????????? struct skb_shared_info *si;
>>> +??????????? int i;
>>> +
>>> +??????????? si = skb_shinfo(skb);
>>> +
>>> +??????????? for (i = 0; i < si->nr_frags; i++) {
>>> +??????????????? skb_frag_t *skb_frag = &si->frags[i];
>>> +??????????????? void *va = page_to_virt(skb_frag->bv_page);
>>> +
>>> +??????????????? /* We will use 'page_to_virt()' for userspace page here,
>>> +???????????????? * because virtio layer will call 'virt_to_phys()' later
>>> +???????????????? * to fill buffer descriptor. We don't touch memory at
>>> +???????????????? * "virtual" address of this page.
>>> +???????????????? */
>>> +??????????????? sg_init_one(&bufs[i + 1],
>>> +??????????????????????? va + skb_frag->bv_offset,
>>> +??????????????????????? skb_frag->bv_len);
>>> +??????????????? sgs[out_sg++] = &bufs[i + 1];
>>> +??????????? }
>>> +??????? } else {
>>> +??????????? if (skb->len > 0) {
>>
>> Should we do the same check (skb->len > 0) for nonlinear skb as well?
>> Or do the nonlinear ones necessarily have len > 0?
>
>Yes, non-linear skb always has 'data_len' > 0, e.g. such skbs always have some
>data in it.
Okay, makes sense ;-)
Thanks,
Stefano
>
>Thanks, Arseniy
>
>>
>>> +??????????????? sg_init_one(&bufs[1], skb->data, skb->len);
>>> +??????????????? sgs[out_sg++] = &bufs[1];
>>> +??????????? }
>>>
>> ?? ^
>> Blank line that we can remove.
>>
>> Stefano
>>
>>> -??????? sg_init_one(&hdr, virtio_vsock_hdr(skb), sizeof(*virtio_vsock_hdr(skb)));
>>> -??????? sgs[out_sg++] = &hdr;
>>> -??????? if (skb->len > 0) {
>>> -??????????? sg_init_one(&buf, skb->data, skb->len);
>>> -??????????? sgs[out_sg++] = &buf;
>>> ??????? }
>>>
>>> ??????? ret = virtqueue_add_sgs(vq, sgs, out_sg, in_sg, skb, GFP_KERNEL);
>>> --?
>>> 2.25.1
>>>
>>
>