6.1-stable review patch. If anyone has any objections, please let me know.
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From: Maciej Fijalkowski maciej.fijalkowski@intel.com
[ Upstream commit 469748429ac81f0a6a344637fc9d3b1d16a9f3d8 ]
Currently ice driver's .ndo_bpf callback brings interface down and up independently of XDP resources' presence. This is only needed when either these resources have to be configured or removed. It means that if one is switching XDP programs on-the-fly with running traffic, packets will be dropped.
To avoid this, compare early on ice_xdp_setup_prog() state of incoming bpf_prog pointer vs the bpf_prog pointer that is already assigned to VSI. Do the swap in case VSI has bpf_prog and incoming one are non-NULL.
Lastly, while at it, put old bpf_prog *after* the update of Rx ring's bpf_prog pointer. In theory previous code could expose us to a state where Rx ring's bpf_prog would still be referring to old_prog that got released with earlier bpf_prog_put().
Signed-off-by: Maciej Fijalkowski maciej.fijalkowski@intel.com Acked-by: Toke Høiland-Jørgensen toke@redhat.com Reviewed-by: Alexander Lobakin aleksander.lobakin@intel.com Tested-by: Chandan Kumar Rout chandanx.rout@intel.com (A Contingent Worker at Intel) Signed-off-by: Tony Nguyen anthony.l.nguyen@intel.com Stable-dep-of: 04c7e14e5b0b ("ice: do not bring the VSI up, if it was down before the XDP setup") Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/ethernet/intel/ice/ice_main.c | 19 +++++++++---------- 1 file changed, 9 insertions(+), 10 deletions(-)
diff --git a/drivers/net/ethernet/intel/ice/ice_main.c b/drivers/net/ethernet/intel/ice/ice_main.c index cd9bcc3536fb..1973b032fe05 100644 --- a/drivers/net/ethernet/intel/ice/ice_main.c +++ b/drivers/net/ethernet/intel/ice/ice_main.c @@ -2633,11 +2633,11 @@ static void ice_vsi_assign_bpf_prog(struct ice_vsi *vsi, struct bpf_prog *prog) int i;
old_prog = xchg(&vsi->xdp_prog, prog); - if (old_prog) - bpf_prog_put(old_prog); - ice_for_each_rxq(vsi, i) WRITE_ONCE(vsi->rx_rings[i]->xdp_prog, vsi->xdp_prog); + + if (old_prog) + bpf_prog_put(old_prog); }
/** @@ -2917,6 +2917,12 @@ ice_xdp_setup_prog(struct ice_vsi *vsi, struct bpf_prog *prog, return -EOPNOTSUPP; }
+ /* hot swap progs and avoid toggling link */ + if (ice_is_xdp_ena_vsi(vsi) == !!prog) { + ice_vsi_assign_bpf_prog(vsi, prog); + return 0; + } + /* need to stop netdev while setting up the program for Rx rings */ if (if_running && !test_and_set_bit(ICE_VSI_DOWN, vsi->state)) { ret = ice_down(vsi); @@ -2947,13 +2953,6 @@ ice_xdp_setup_prog(struct ice_vsi *vsi, struct bpf_prog *prog, xdp_ring_err = ice_realloc_zc_buf(vsi, false); if (xdp_ring_err) NL_SET_ERR_MSG_MOD(extack, "Freeing XDP Rx resources failed"); - } else { - /* safe to call even when prog == vsi->xdp_prog as - * dev_xdp_install in net/core/dev.c incremented prog's - * refcount so corresponding bpf_prog_put won't cause - * underflow - */ - ice_vsi_assign_bpf_prog(vsi, prog); }
if (if_running)