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net/i40e: Fix concurrency issues between config flow and XSK 

Use synchronize_rcu to wait until the XSK wakeup function finishes
before destroying the resources it uses:

1. i40e_down already calls synchronize_rcu. On i40e_down either
__I40E_VSI_DOWN or __I40E_CONFIG_BUSY is set. Check the latter in
i40e_xsk_wakeup (the former is already checked there).

2. After switching the XDP program, call synchronize_rcu to let
i40e_xsk_wakeup exit before the XDP program is freed.

3. Changing the number of channels brings the interface down (see
i40e_prep_for_reset and i40e_pf_quiesce_all_vsi).

4. Disabling UMEM sets __I40E_CONFIG_BUSY, too.

Signed-off-by: Maxim Mikityanskiy <maximmi@mellanox.com>
Signed-off-by: Björn Töpel <bjorn.topel@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20191217162023.16011-4-maximmi@mellanox.com
This commit is contained in:
Maxim Mikityanskiy 2019-12-17 16:20:45 +00:00 committed by Daniel Borkmann
parent 9cf88808ad
commit b3873a5be7
3 changed files with 12 additions and 4 deletions
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2
drivers/net/ethernet/intel/i40e/i40e.h
View File

@ -1152,7 +1152,7 @@ void i40e_set_fec_in_flags(u8 fec_cfg, u32 *flags);
static inline bool i40e_enabled_xdp_vsi(struct i40e_vsi *vsi)
{
return !!vsi->xdp_prog;
return !!READ_ONCE(vsi->xdp_prog);
}
int i40e_create_queue_channel(struct i40e_vsi *vsi, struct i40e_channel *ch);

10
drivers/net/ethernet/intel/i40e/i40e_main.c
View File

@ -6823,8 +6823,8 @@ void i40e_down(struct i40e_vsi *vsi)
for (i = 0; i < vsi->num_queue_pairs; i++) {
i40e_clean_tx_ring(vsi->tx_rings[i]);
if (i40e_enabled_xdp_vsi(vsi)) {
/* Make sure that in-progress ndo_xdp_xmit
* calls are completed.
/* Make sure that in-progress ndo_xdp_xmit and
* ndo_xsk_wakeup calls are completed.
*/
synchronize_rcu();
i40e_clean_tx_ring(vsi->xdp_rings[i]);
@ -12546,8 +12546,12 @@ static int i40e_xdp_setup(struct i40e_vsi *vsi,
old_prog = xchg(&vsi->xdp_prog, prog);
if (need_reset)
if (need_reset) {
if (!prog)
/* Wait until ndo_xsk_wakeup completes. */
synchronize_rcu();
i40e_reset_and_rebuild(pf, true, true);
}
for (i = 0; i < vsi->num_queue_pairs; i++)
WRITE_ONCE(vsi->rx_rings[i]->xdp_prog, vsi->xdp_prog);

4
drivers/net/ethernet/intel/i40e/i40e_xsk.c
View File

@ -787,8 +787,12 @@ int i40e_xsk_wakeup(struct net_device *dev, u32 queue_id, u32 flags)
{
struct i40e_netdev_priv *np = netdev_priv(dev);
struct i40e_vsi *vsi = np->vsi;
struct i40e_pf *pf = vsi->back;
struct i40e_ring *ring;
if (test_bit(__I40E_CONFIG_BUSY, pf->state))
return -ENETDOWN;
if (test_bit(__I40E_VSI_DOWN, vsi->state))
return -ENETDOWN;