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Subject[PATCH iwl-net 2/3] ice: add flag to distinguish reset from .ndo_bpf in XDP rings config
Date
Commit 6624e780a577 ("ice: split ice_vsi_setup into smaller functions")
has placed ice_vsi_free_q_vectors() after ice_destroy_xdp_rings() in
the rebuild process. The behaviour of the XDP rings config functions is
context-dependent, so the change of order has led to
ice_destroy_xdp_rings() doing additional work and removing XDP prog, when
it was supposed to be preserved.

Also, dependency on the PF state reset flags creates an additional,
fortunately less common problem:

* PFR is requested e.g. by tx_timeout handler
* .ndo_bpf() is asked to delete the program, calls ice_destroy_xdp_rings(),
but reset flag is set, so rings are destroyed without deleting the
program
* ice_vsi_rebuild tries to delete non-existent XDP rings, because the
program is still on the VSI
* system crashes

With a similar race, when requested to attach a program,
ice_prepare_xdp_rings() can actually skip setting the program in the VSI
and nevertheless report success.

Instead of reverting to the old order of function calls, add an enum
argument to both ice_prepare_xdp_rings() and ice_destroy_xdp_rings() in
order to distinguish between calls from rebuild and .ndo_bpf().

Fixes: efc2214b6047 ("ice: Add support for XDP")
Reviewed-by: Igor Bagnucki <igor.bagnucki@intel.com>
Signed-off-by: Larysa Zaremba <larysa.zaremba@intel.com>
---
drivers/net/ethernet/intel/ice/ice.h | 11 +++++++++--
drivers/net/ethernet/intel/ice/ice_lib.c | 5 +++--
drivers/net/ethernet/intel/ice/ice_main.c | 22 ++++++++++++----------
3 files changed, 24 insertions(+), 14 deletions(-)

diff --git a/drivers/net/ethernet/intel/ice/ice.h b/drivers/net/ethernet/intel/ice/ice.h
index d4d840729bda..b91b2594b29d 100644
--- a/drivers/net/ethernet/intel/ice/ice.h
+++ b/drivers/net/ethernet/intel/ice/ice.h
@@ -930,9 +930,16 @@ int ice_down(struct ice_vsi *vsi);
int ice_down_up(struct ice_vsi *vsi);
int ice_vsi_cfg_lan(struct ice_vsi *vsi);
struct ice_vsi *ice_lb_vsi_setup(struct ice_pf *pf, struct ice_port_info *pi);
+
+enum ice_xdp_cfg {
+ ICE_XDP_CFG_FULL, /* Fully apply new config in .ndo_bpf() */
+ ICE_XDP_CFG_PART, /* Save/use part of config in VSI rebuild */
+};
+
int ice_vsi_determine_xdp_res(struct ice_vsi *vsi);
-int ice_prepare_xdp_rings(struct ice_vsi *vsi, struct bpf_prog *prog);
-int ice_destroy_xdp_rings(struct ice_vsi *vsi);
+int ice_prepare_xdp_rings(struct ice_vsi *vsi, struct bpf_prog *prog,
+ enum ice_xdp_cfg cfg_type);
+int ice_destroy_xdp_rings(struct ice_vsi *vsi, enum ice_xdp_cfg cfg_type);
int
ice_xdp_xmit(struct net_device *dev, int n, struct xdp_frame **frames,
u32 flags);
diff --git a/drivers/net/ethernet/intel/ice/ice_lib.c b/drivers/net/ethernet/intel/ice/ice_lib.c
index c0a7ff6c7e87..dd8b374823ee 100644
--- a/drivers/net/ethernet/intel/ice/ice_lib.c
+++ b/drivers/net/ethernet/intel/ice/ice_lib.c
@@ -2285,7 +2285,8 @@ static int ice_vsi_cfg_def(struct ice_vsi *vsi)
ret = ice_vsi_determine_xdp_res(vsi);
if (ret)
goto unroll_vector_base;
- ret = ice_prepare_xdp_rings(vsi, vsi->xdp_prog);
+ ret = ice_prepare_xdp_rings(vsi, vsi->xdp_prog,
+ ICE_XDP_CFG_PART);
if (ret)
goto unroll_vector_base;
}
@@ -2429,7 +2430,7 @@ void ice_vsi_decfg(struct ice_vsi *vsi)
/* return value check can be skipped here, it always returns
* 0 if reset is in progress
*/
- ice_destroy_xdp_rings(vsi);
+ ice_destroy_xdp_rings(vsi, ICE_XDP_CFG_PART);

ice_vsi_clear_rings(vsi);
ice_vsi_free_q_vectors(vsi);
diff --git a/drivers/net/ethernet/intel/ice/ice_main.c b/drivers/net/ethernet/intel/ice/ice_main.c
index f60c022f7960..2a270aacd24a 100644
--- a/drivers/net/ethernet/intel/ice/ice_main.c
+++ b/drivers/net/ethernet/intel/ice/ice_main.c
@@ -2711,10 +2711,12 @@ static void ice_vsi_assign_bpf_prog(struct ice_vsi *vsi, struct bpf_prog *prog)
* ice_prepare_xdp_rings - Allocate, configure and setup Tx rings for XDP
* @vsi: VSI to bring up Tx rings used by XDP
* @prog: bpf program that will be assigned to VSI
+ * @cfg_type: create from scratch or restore the existing configuration
*
* Return 0 on success and negative value on error
*/
-int ice_prepare_xdp_rings(struct ice_vsi *vsi, struct bpf_prog *prog)
+int ice_prepare_xdp_rings(struct ice_vsi *vsi, struct bpf_prog *prog,
+ enum ice_xdp_cfg cfg_type)
{
u16 max_txqs[ICE_MAX_TRAFFIC_CLASS] = { 0 };
int xdp_rings_rem = vsi->num_xdp_txq;
@@ -2790,7 +2792,7 @@ int ice_prepare_xdp_rings(struct ice_vsi *vsi, struct bpf_prog *prog)
* taken into account at the end of ice_vsi_rebuild, where
* ice_cfg_vsi_lan is being called
*/
- if (ice_is_reset_in_progress(pf->state))
+ if (cfg_type == ICE_XDP_CFG_PART)
return 0;

/* tell the Tx scheduler that right now we have
@@ -2842,22 +2844,21 @@ int ice_prepare_xdp_rings(struct ice_vsi *vsi, struct bpf_prog *prog)
/**
* ice_destroy_xdp_rings - undo the configuration made by ice_prepare_xdp_rings
* @vsi: VSI to remove XDP rings
+ * @cfg_type: disable XDP permanently or allow it to be restored later
*
* Detach XDP rings from irq vectors, clean up the PF bitmap and free
* resources
*/
-int ice_destroy_xdp_rings(struct ice_vsi *vsi)
+int ice_destroy_xdp_rings(struct ice_vsi *vsi, enum ice_xdp_cfg cfg_type)
{
u16 max_txqs[ICE_MAX_TRAFFIC_CLASS] = { 0 };
struct ice_pf *pf = vsi->back;
int i, v_idx;

/* q_vectors are freed in reset path so there's no point in detaching
- * rings; in case of rebuild being triggered not from reset bits
- * in pf->state won't be set, so additionally check first q_vector
- * against NULL
+ * rings
*/
- if (ice_is_reset_in_progress(pf->state) || !vsi->q_vectors[0])
+ if (cfg_type == ICE_XDP_CFG_PART)
goto free_qmap;

ice_for_each_q_vector(vsi, v_idx) {
@@ -2898,7 +2899,7 @@ int ice_destroy_xdp_rings(struct ice_vsi *vsi)
if (static_key_enabled(&ice_xdp_locking_key))
static_branch_dec(&ice_xdp_locking_key);

- if (ice_is_reset_in_progress(pf->state) || !vsi->q_vectors[0])
+ if (cfg_type == ICE_XDP_CFG_PART)
return 0;

ice_vsi_assign_bpf_prog(vsi, NULL);
@@ -3009,7 +3010,8 @@ ice_xdp_setup_prog(struct ice_vsi *vsi, struct bpf_prog *prog,
if (xdp_ring_err) {
NL_SET_ERR_MSG_MOD(extack, "Not enough Tx resources for XDP");
} else {
- xdp_ring_err = ice_prepare_xdp_rings(vsi, prog);
+ xdp_ring_err = ice_prepare_xdp_rings(vsi, prog,
+ ICE_XDP_CFG_FULL);
if (xdp_ring_err)
NL_SET_ERR_MSG_MOD(extack, "Setting up XDP Tx resources failed");
}
@@ -3020,7 +3022,7 @@ ice_xdp_setup_prog(struct ice_vsi *vsi, struct bpf_prog *prog,
NL_SET_ERR_MSG_MOD(extack, "Setting up XDP Rx resources failed");
} else if (ice_is_xdp_ena_vsi(vsi) && !prog) {
xdp_features_clear_redirect_target(vsi->netdev);
- xdp_ring_err = ice_destroy_xdp_rings(vsi);
+ xdp_ring_err = ice_destroy_xdp_rings(vsi, ICE_XDP_CFG_FULL);
if (xdp_ring_err)
NL_SET_ERR_MSG_MOD(extack, "Freeing XDP Tx resources failed");
/* reallocate Rx queues that were used for zero-copy */
--
2.43.0

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