Commit 184367dc authored by Haiyang Zhang's avatar Haiyang Zhang Committed by David S. Miller
Browse files

hv_netvsc: Fix XDP refcnt for synthetic and VF NICs 



The caller of XDP_SETUP_PROG has already incremented refcnt in
__bpf_prog_get(), so drivers should only increment refcnt by
num_queues - 1.

To fix the issue, update netvsc_xdp_set() to add the correct number
to refcnt.

Hold a refcnt in netvsc_xdp_set()’s other caller, netvsc_attach().

And, do the same in netvsc_vf_setxdp(). Otherwise, every time when VF is
removed and added from the host side, the refcnt will be decreased by one,
which may cause page fault when unloading xdp program.

Fixes: 351e1581 ("hv_netvsc: Add XDP support")
Signed-off-by: default avatarHaiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 6910fe95

drivers/net/hyperv/netvsc_bpf.c

+11 −2
Original line number Diff line number Diff line
@@ -120,7 +120,7 @@ int netvsc_xdp_set(struct net_device *dev, struct bpf_prog *prog, 
	}



	if (prog)

		bpf_prog_add(prog, nvdev->num_chn);

		bpf_prog_add(prog, nvdev->num_chn - 1);



	for (i = 0; i < nvdev->num_chn; i++)

		rcu_assign_pointer(nvdev->chan_table[i].bpf_prog, prog);
@@ -136,6 +136,7 @@ int netvsc_vf_setxdp(struct net_device *vf_netdev, struct bpf_prog *prog) 
{

	struct netdev_bpf xdp;

	bpf_op_t ndo_bpf;

	int ret;



	ASSERT_RTNL();
@@ -148,10 +149,18 @@ int netvsc_vf_setxdp(struct net_device *vf_netdev, struct bpf_prog *prog) 


	memset(&xdp, 0, sizeof(xdp));



	if (prog)

		bpf_prog_inc(prog);



	xdp.command = XDP_SETUP_PROG;

	xdp.prog = prog;



	return ndo_bpf(vf_netdev, &xdp);

	ret = ndo_bpf(vf_netdev, &xdp);



	if (ret && prog)

		bpf_prog_put(prog);



	return ret;

}



static u32 netvsc_xdp_query(struct netvsc_device *nvdev)

drivers/net/hyperv/netvsc_drv.c

+4 −1
Original line number Diff line number Diff line
@@ -1059,10 +1059,13 @@ static int netvsc_attach(struct net_device *ndev, 


	prog = dev_info->bprog;

	if (prog) {

		bpf_prog_inc(prog);

		ret = netvsc_xdp_set(ndev, prog, NULL, nvdev);

		if (ret)

		if (ret) {

			bpf_prog_put(prog);

			goto err1;

		}

	}



	/* In any case device is now ready */

	netif_device_attach(ndev);

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