[PATCH 5.16 188/285] ice: synchronize_rcu() when terminating rings

Greg Kroah-Hartman
2022-04-12T08:26:42Z

From: Maciej Fijalkowski <maciej.fijalkowski@intel.com>

[ Upstream commit f9124c68f05ffdb87a47e3ea6d5fae9dad7cb6eb ]

Unfortunately, the ice driver doesn't respect the RCU critical section that
XSK wakeup is surrounded with. To fix this, add synchronize_rcu() calls to
paths that destroy resources that might be in use.

This was addressed in other AF_XDP ZC enabled drivers, for reference see
for example commit b3873a5be757 ("net/i40e: Fix concurrency issues
between config flow and XSK")

Fixes: efc2214b6047 ("ice: Add support for XDP")
Fixes: 2d4238f55697 ("ice: Add support for AF_XDP")
Signed-off-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Tested-by: Shwetha Nagaraju <shwetha.nagaraju@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/ethernet/intel/ice/ice.h | 2 +-
drivers/net/ethernet/intel/ice/ice_main.c | 4 +++-
drivers/net/ethernet/intel/ice/ice_xsk.c | 4 +++-
3 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/intel/ice/ice.h b/drivers/net/ethernet/intel/ice/ice.h
index a47471586047..446373623f47 100644
--- a/drivers/net/ethernet/intel/ice/ice.h
+++ b/drivers/net/ethernet/intel/ice/ice.h
@@ -671,7 +671,7 @@ static inline struct ice_pf *ice_netdev_to_pf(struct net_device *netdev)

static inline bool ice_is_xdp_ena_vsi(struct ice_vsi *vsi)
{
- return !!vsi->xdp_prog;
+ return !!READ_ONCE(vsi->xdp_prog);
}

static inline void ice_set_ring_xdp(struct ice_tx_ring *ring)
diff --git a/drivers/net/ethernet/intel/ice/ice_main.c b/drivers/net/ethernet/intel/ice/ice_main.c
index 523877c2f8b6..cd2fb24c3005 100644
--- a/drivers/net/ethernet/intel/ice/ice_main.c
+++ b/drivers/net/ethernet/intel/ice/ice_main.c
@@ -2724,8 +2724,10 @@ int ice_destroy_xdp_rings(struct ice_vsi *vsi)

ice_for_each_xdp_txq(vsi, i)
if (vsi->xdp_rings[i]) {
- if (vsi->xdp_rings[i]->desc)
+ if (vsi->xdp_rings[i]->desc) {
+ synchronize_rcu();
ice_free_tx_ring(vsi->xdp_rings[i]);
+ }
kfree_rcu(vsi->xdp_rings[i], rcu);
vsi->xdp_rings[i] = NULL;
}
diff --git a/drivers/net/ethernet/intel/ice/ice_xsk.c b/drivers/net/ethernet/intel/ice/ice_xsk.c
index ac97cf3c5804..dfef1e75469d 100644
--- a/drivers/net/ethernet/intel/ice/ice_xsk.c
+++ b/drivers/net/ethernet/intel/ice/ice_xsk.c
@@ -41,8 +41,10 @@ static void ice_qp_reset_stats(struct ice_vsi *vsi, u16 q_idx)
static void ice_qp_clean_rings(struct ice_vsi *vsi, u16 q_idx)
{
ice_clean_tx_ring(vsi->tx_rings[q_idx]);
- if (ice_is_xdp_ena_vsi(vsi))
+ if (ice_is_xdp_ena_vsi(vsi)) {
+ synchronize_rcu();
ice_clean_tx_ring(vsi->xdp_rings[q_idx]);
+ }
ice_clean_rx_ring(vsi->rx_rings[q_idx]);
}

--
2.35.1