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Message-ID: <ebee740a-95df-ed52-6274-a9340e8dc9d2@sberdevices.ru>
Date: Mon, 6 Feb 2023 06:59:21 +0000
From: Arseniy Krasnov <AVKrasnov@...rdevices.ru>
To: Stefan Hajnoczi <stefanha@...hat.com>,
Stefano Garzarella <sgarzare@...hat.com>,
"Michael S. Tsirkin" <mst@...hat.com>,
Jason Wang <jasowang@...hat.com>,
"David S. Miller" <davem@...emloft.net>,
Eric Dumazet <edumazet@...gle.com>,
Jakub Kicinski <kuba@...nel.org>,
Paolo Abeni <pabeni@...hat.com>,
Arseniy Krasnov <AVKrasnov@...rdevices.ru>,
"Krasnov Arseniy" <oxffffaa@...il.com>
CC: "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"kvm@...r.kernel.org" <kvm@...r.kernel.org>,
"virtualization@...ts.linux-foundation.org"
<virtualization@...ts.linux-foundation.org>,
"netdev@...r.kernel.org" <netdev@...r.kernel.org>,
kernel <kernel@...rdevices.ru>
Subject: [RFC PATCH v1 06/12] vsock/virtio: non-linear skb handling for TAP
dev
For TAP device new skb is created and data from the current skb is
copied to it. This adds copying data from non-linear skb to new
the skb.
Signed-off-by: Arseniy Krasnov <AVKrasnov@...rdevices.ru>
---
net/vmw_vsock/virtio_transport_common.c | 43 +++++++++++++++++++++++--
1 file changed, 40 insertions(+), 3 deletions(-)
diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
index a1581c77cf84..05ce97b967ad 100644
--- a/net/vmw_vsock/virtio_transport_common.c
+++ b/net/vmw_vsock/virtio_transport_common.c
@@ -101,6 +101,39 @@ virtio_transport_alloc_skb(struct virtio_vsock_pkt_info *info,
return NULL;
}
+static void virtio_transport_copy_nonlinear_skb(struct sk_buff *skb,
+ void *dst,
+ size_t len)
+{
+ size_t rest_len = len;
+
+ while (rest_len && virtio_vsock_skb_has_frags(skb)) {
+ struct bio_vec *curr_vec;
+ size_t curr_vec_end;
+ size_t to_copy;
+ int curr_frag;
+ int curr_offs;
+
+ curr_frag = VIRTIO_VSOCK_SKB_CB(skb)->curr_frag;
+ curr_offs = VIRTIO_VSOCK_SKB_CB(skb)->frag_off;
+ curr_vec = &skb_shinfo(skb)->frags[curr_frag];
+
+ curr_vec_end = curr_vec->bv_offset + curr_vec->bv_len;
+ to_copy = min(rest_len, (size_t)(curr_vec_end - curr_offs));
+
+ memcpy(dst, page_to_virt(curr_vec->bv_page) + curr_offs,
+ to_copy);
+
+ rest_len -= to_copy;
+ VIRTIO_VSOCK_SKB_CB(skb)->frag_off += to_copy;
+
+ if (VIRTIO_VSOCK_SKB_CB(skb)->frag_off == (curr_vec_end)) {
+ VIRTIO_VSOCK_SKB_CB(skb)->curr_frag++;
+ VIRTIO_VSOCK_SKB_CB(skb)->frag_off = 0;
+ }
+ }
+}
+
/* Packet capture */
static struct sk_buff *virtio_transport_build_skb(void *opaque)
{
@@ -109,7 +142,6 @@ static struct sk_buff *virtio_transport_build_skb(void *opaque)
struct af_vsockmon_hdr *hdr;
struct sk_buff *skb;
size_t payload_len;
- void *payload_buf;
/* A packet could be split to fit the RX buffer, so we can retrieve
* the payload length from the header and the buffer pointer taking
@@ -117,7 +149,6 @@ static struct sk_buff *virtio_transport_build_skb(void *opaque)
*/
pkt_hdr = virtio_vsock_hdr(pkt);
payload_len = pkt->len;
- payload_buf = pkt->data;
skb = alloc_skb(sizeof(*hdr) + sizeof(*pkt_hdr) + payload_len,
GFP_ATOMIC);
@@ -160,7 +191,13 @@ static struct sk_buff *virtio_transport_build_skb(void *opaque)
skb_put_data(skb, pkt_hdr, sizeof(*pkt_hdr));
if (payload_len) {
- skb_put_data(skb, payload_buf, payload_len);
+ if (skb_is_nonlinear(skb)) {
+ void *data = skb_put(skb, payload_len);
+
+ virtio_transport_copy_nonlinear_skb(skb, data, payload_len);
+ } else {
+ skb_put_data(skb, pkt->data, payload_len);
+ }
}
return skb;
--
2.25.1
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