[RFC][b/azure][PATCH 1/3] netvsc: unshare skb in VF rx handler

[Ioanna Alifieraki]

From: Stephen Hemminger <stephen at networkplumber.org>

BugLink: https://bugs.launchpad.net/bugs/1831254

The netvsc VF skb handler should make sure that skb is not
shared. Similar logic already exists in bonding and team device
drivers.

This is not an issue in practice because the VF devicex
does not send up shared skb's. But the netvsc driver
should do the right thing if it did.

Fixes: 0c195567a8f6 ("netvsc: transparent VF management")
Signed-off-by: Stephen Hemminger <sthemmin at microsoft.com>
Signed-off-by: David S. Miller <davem at davemloft.net>
(cherry picked from commit 996ed04741467f6d1552440c92988b132a9487ec)
Signed-off-by: Ioanna Alifieraki <ioanna-maria.alifieraki at canonical.com>
---
 drivers/net/hyperv/netvsc_drv.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c
index c0fc30a1f600..c86c79949097 100644
--- a/drivers/net/hyperv/netvsc_drv.c
+++ b/drivers/net/hyperv/netvsc_drv.c
@@ -1836,6 +1836,12 @@ static rx_handler_result_t netvsc_vf_handle_frame(struct sk_buff **pskb)
 	struct netvsc_vf_pcpu_stats *pcpu_stats
 		 = this_cpu_ptr(ndev_ctx->vf_stats);
 
+	skb = skb_share_check(skb, GFP_ATOMIC);
+	if (unlikely(!skb))
+		return RX_HANDLER_CONSUMED;
+
+	*pskb = skb;
+
 	skb->dev = ndev;
 
 	u64_stats_update_begin(&pcpu_stats->syncp);
-- 
2.17.1