After XDP configuration is completed, we bring the interface up
unconditionally, regardless of its state before the call to .ndo_bpf().

Preserve the information whether the interface had to be brought down and
later bring it up only in such case.

Fixes: efc2214b6047 ("ice: Add support for XDP")
Reviewed-by: Wojciech Drewek <wojciech.drewek@intel.com>
Signed-off-by: Larysa Zaremba <larysa.zaremba@intel.com>
---
 drivers/net/ethernet/intel/ice/ice_main.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/intel/ice/ice_main.c b/drivers/net/ethernet/intel/ice/ice_main.c
index d7cc641643f8..d83cde431fa5 100644
--- a/drivers/net/ethernet/intel/ice/ice_main.c
+++ b/drivers/net/ethernet/intel/ice/ice_main.c
@@ -3000,8 +3000,8 @@ ice_xdp_setup_prog(struct ice_vsi *vsi, struct bpf_prog *prog,
 		   struct netlink_ext_ack *extack)
 {
 	unsigned int frame_size = vsi->netdev->mtu + ICE_ETH_PKT_HDR_PAD;
-	bool if_running = netif_running(vsi->netdev);
 	int ret = 0, xdp_ring_err = 0;
+	bool if_running;
 
 	if (prog && !prog->aux->xdp_has_frags) {
 		if (frame_size > ice_max_xdp_frame_size(vsi)) {
@@ -3018,8 +3018,11 @@ ice_xdp_setup_prog(struct ice_vsi *vsi, struct bpf_prog *prog,
 		return 0;
 	}
 
+	if_running = netif_running(vsi->netdev) &&
+		     !test_and_set_bit(ICE_VSI_DOWN, vsi->state);
+
 	/* need to stop netdev while setting up the program for Rx rings */
-	if (if_running && !test_and_set_bit(ICE_VSI_DOWN, vsi->state)) {
+	if (if_running) {
 		ret = ice_down(vsi);
 		if (ret) {
 			NL_SET_ERR_MSG_MOD(extack, "Preparing device for XDP attach failed");
-- 
2.43.0

>-----Original Message-----
>From: Intel-wired-lan <intel-wired-lan-bounces@osuosl.org> On Behalf Of
>Zaremba, Larysa
>Sent: Wednesday, July 24, 2024 10:19 PM
>To: intel-wired-lan@lists.osuosl.org
>Cc: Drewek, Wojciech <wojciech.drewek@intel.com>; Fijalkowski, Maciej
><maciej.fijalkowski@intel.com>; Jesper Dangaard Brouer <hawk@kernel.org>;
>Daniel Borkmann <daniel@iogearbox.net>; Zaremba, Larysa
><larysa.zaremba@intel.com>; netdev@vger.kernel.org; John Fastabend
><john.fastabend@gmail.com>; Alexei Starovoitov <ast@kernel.org>; linux-
>kernel@vger.kernel.org; Eric Dumazet <edumazet@google.com>; Kubiak,
>Michal <michal.kubiak@intel.com>; Nguyen, Anthony L
><anthony.l.nguyen@intel.com>; Nambiar, Amritha
><amritha.nambiar@intel.com>; Keller, Jacob E <jacob.e.keller@intel.com>;
>Jakub Kicinski <kuba@kernel.org>; bpf@vger.kernel.org; Paolo Abeni
><pabeni@redhat.com>; David S. Miller <davem@davemloft.net>; Karlsson,
>Magnus <magnus.karlsson@intel.com>
>Subject: [Intel-wired-lan] [PATCH iwl-net v2 6/6] ice: do not bring the VSI up, if
>it was down before the XDP setup
>
>After XDP configuration is completed, we bring the interface up unconditionally,
>regardless of its state before the call to .ndo_bpf().
>
>Preserve the information whether the interface had to be brought down and
>later bring it up only in such case.
>
>Fixes: efc2214b6047 ("ice: Add support for XDP")
>Reviewed-by: Wojciech Drewek <wojciech.drewek@intel.com>
>Signed-off-by: Larysa Zaremba <larysa.zaremba@intel.com>
>---
> drivers/net/ethernet/intel/ice/ice_main.c | 7 +++++--
> 1 file changed, 5 insertions(+), 2 deletions(-)
>

Tested-by: Chandan Kumar Rout <chandanx.rout@intel.com> (A Contingent Worker at Intel)

On 7/24/2024 9:48 AM, Larysa Zaremba wrote:
> After XDP configuration is completed, we bring the interface up
> unconditionally, regardless of its state before the call to .ndo_bpf().
> 
> Preserve the information whether the interface had to be brought down and
> later bring it up only in such case.
> 
> Fixes: efc2214b6047 ("ice: Add support for XDP")
> Reviewed-by: Wojciech Drewek <wojciech.drewek@intel.com>
> Signed-off-by: Larysa Zaremba <larysa.zaremba@intel.com>
> ---
>  drivers/net/ethernet/intel/ice/ice_main.c | 7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/net/ethernet/intel/ice/ice_main.c b/drivers/net/ethernet/intel/ice/ice_main.c
> index d7cc641643f8..d83cde431fa5 100644
> --- a/drivers/net/ethernet/intel/ice/ice_main.c
> +++ b/drivers/net/ethernet/intel/ice/ice_main.c
> @@ -3000,8 +3000,8 @@ ice_xdp_setup_prog(struct ice_vsi *vsi, struct bpf_prog *prog,
>  		   struct netlink_ext_ack *extack)
>  {
>  	unsigned int frame_size = vsi->netdev->mtu + ICE_ETH_PKT_HDR_PAD;
> -	bool if_running = netif_running(vsi->netdev);
>  	int ret = 0, xdp_ring_err = 0;
> +	bool if_running;
>  
>  	if (prog && !prog->aux->xdp_has_frags) {
>  		if (frame_size > ice_max_xdp_frame_size(vsi)) {
> @@ -3018,8 +3018,11 @@ ice_xdp_setup_prog(struct ice_vsi *vsi, struct bpf_prog *prog,
>  		return 0;
>  	}
>  
> +	if_running = netif_running(vsi->netdev) &&
> +		     !test_and_set_bit(ICE_VSI_DOWN, vsi->state);
> +
>  	/* need to stop netdev while setting up the program for Rx rings */
> -	if (if_running && !test_and_set_bit(ICE_VSI_DOWN, vsi->state)) {
> +	if (if_running) {
>  		ret = ice_down(vsi);
>  		if (ret) {
>  			NL_SET_ERR_MSG_MOD(extack, "Preparing device for XDP attach failed");

This diff lacks the appropriate context that can help explain how it works:

> 
>         if (if_running)
>                 ret = ice_up(vsi);
> 
>         if (!ret && prog)
>                 ice_vsi_rx_napi_schedule(vsi);
> 
>         return (ret || xdp_ring_err) ? -ENOMEM : 0;

By changing if_running to include the VSI state flag, we ensure the call
to ice_up is correctly conditional.

Good fix. If I understand right, it depends on the other synchronization
fixes to work correctly so that the VSI state won't be changed on us.

Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>