[Intel-wired-lan] [PATCH net] ice: Fix broken IFF_ALLMULTI handling

[Keller, Jacob E <jacob.e.keller@intel.com>]

On 3/21/2022 12:17 PM, Ivan Vecera wrote:
> Handling of all-multicast flag and associated multicast promiscuous
> mode is broken in ice driver. When a user switches allmulticast
> flag on or off the driver checks whether any VLANs are configured
> over the interface (except default VLAN 0).
> 
> If any extra VLANs are registered it enables multicast promiscuous
> mode for all these VLANs (including default VLAN 0) using
> ICE_SW_LKUP_PROMISC_VLAN look-up type. In this situation all
> multicast packets tagged with known VLAN ID or untagged are received
> and multicast packets tagged with unknown VLAN ID ignored.
> 
> If no extra VLANs are registered (so only VLAN 0 exists) it enables
> multicast promiscuous mode for VLAN 0 and uses ICE_SW_LKUP_PROMISC
> look-up type. In this situation any multicast packets including
> tagged ones are received.
> 
> The driver handles IFF_ALLMULTI in ice_vsi_sync_fltr() this way:
> 
> ice_vsi_sync_fltr() {
>   ...
>   if (changed_flags & IFF_ALLMULTI) {
>     if (netdev->flags & IFF_ALLMULTI) {
>       if (vsi->num_vlans > 1)
>         ice_set_promisc(..., ICE_MCAST_VLAN_PROMISC_BITS);
>       else
>         ice_set_promisc(..., ICE_MCAST_PROMISC_BITS);
>     } else {
>       if (vsi->num_vlans > 1)
>         ice_clear_promisc(..., ICE_MCAST_VLAN_PROMISC_BITS);
>       else
>         ice_clear_promisc(..., ICE_MCAST_PROMISC_BITS);
>     }
>   }
>   ...
> }
> 
> The code above depends on value vsi->num_vlan that specifies number
> of VLANs configured over the interface (including VLAN 0) and
> this is problem because that value is modified in NDO callbacks
> ice_vlan_rx_add_vid() and ice_vlan_rx_kill_vid().
> 
> Scenario 1:
> 1. ip link set ens7f0 allmulticast on
> 2. ip link add vlan10 link ens7f0 type vlan id 10
> 3. ip link set ens7f0 allmulticast off
> 4. ip link set ens7f0 allmulticast on
> 
> [1] In this scenario IFF_ALLMULTI is enabled and the driver calls
>     ice_set_promisc(..., ICE_MCAST_PROMISC_BITS) that installs
>     multicast promisc rule with non-VLAN look-up type.
> [2] Then VLAN with ID 10 is added and vsi->num_vlan incremented to 2
> [3] Command switches IFF_ALLMULTI off and the driver calls
>     ice_clear_promisc(..., ICE_MCAST_VLAN_PROMISC_BITS) but this
>     call is effectively NOP because it looks for multicast promisc
>     rules for VLAN 0 and VLAN 10 with VLAN look-up type but no such
>     rules exist. So the all-multicast remains enabled silently
>     in hardware.
> [4] Command tries to switch IFF_ALLMULTI on and the driver calls
>     ice_clear_promisc(..., ICE_MCAST_PROMISC_BITS) but this call
>     fails (-EEXIST) because non-VLAN multicast promisc rule already
>     exists.
> 
> Scenario 2:
> 1. ip link add vlan10 link ens7f0 type vlan id 10
> 2. ip link set ens7f0 allmulticast on
> 3. ip link add vlan20 link ens7f0 type vlan id 20
> 4. ip link del vlan10 ; ip link del vlan20
> 5. ip link set ens7f0 allmulticast off
> 
> [1] VLAN with ID 10 is added and vsi->num_vlan==2
> [2] Command switches IFF_ALLMULTI on and driver installs multicast
>     promisc rules with VLAN look-up type for VLAN 0 and 10
> [3] VLAN with ID 20 is added and vsi->num_vlan==3 but no multicast
>     promisc rules is added for this new VLAN so the interface does
>     not receive MC packets from VLAN 20
> [4] Both VLANs are removed but multicast rule for VLAN 10 remains
>     installed so interface receives multicast packets from VLAN 10
> [5] Command switches IFF_ALLMULTI off and because vsi->num_vlan is 1
>     the driver tries to remove multicast promisc rule for VLAN 0
>     with non-VLAN look-up that does not exist.
>     All-multicast looks disabled from user point of view but it
>     is partially enabled in HW (interface receives all multicast
>     packets either untagged or tagged with VLAN ID 10)
> 
> To resolve these issues the patch introduces these changes:
> 1. Adds handling for IFF_ALLMULTI to ice_vlan_rx_add_vid() and
>    ice_vlan_rx_kill_vid() callbacks. So when VLAN is added/removed
>    and IFF_ALLMULTI is enabled an appropriate multicast promisc
>    rule for that VLAN ID is added/removed.
> 2. In ice_vlan_rx_add_vid() when first VLAN besides VLAN 0 is added
>    so (vsi->num_vlan == 2) and IFF_ALLMULTI is enabled then look-up
>    type for existing multicast promisc rule for VLAN 0 is updated
>    to ICE_MCAST_VLAN_PROMISC_BITS.
> 3. In ice_vlan_rx_kill_vid() when last VLAN besides VLAN 0 is removed
>    so (vsi->num_vlan == 1) and IFF_ALLMULTI is enabled then look-up
>    type for existing multicast promisc rule for VLAN 0 is updated
>    to ICE_MCAST_PROMISC_BITS.
> 4. Both ice_vlan_rx_{add,kill}_vid() have to run under ICE_CFG_BUSY
>    bit protection to avoid races with ice_vsi_sync_fltr() that runs
>    in ice_service_task() context.
> 5. Bit ICE_VSI_VLAN_FLTR_CHANGED is use-less and can be removed.
> 6. Error messages added to ice_fltr_*_vsi_promisc() helper functions
>    to avoid them in their callers
> 7. Small improvements to increase readability
> 
> Fixes: 5eda8afd6bcc ("ice: Add support for PF/VF promiscuous mode")
> Signed-off-by: Ivan Vecera <ivecera@redhat.com>
> ---
>  drivers/net/ethernet/intel/ice/ice.h      |   1 -
>  drivers/net/ethernet/intel/ice/ice_fltr.c |  52 +++++++++-
>  drivers/net/ethernet/intel/ice/ice_main.c | 119 +++++++++++++++-------
>  3 files changed, 131 insertions(+), 41 deletions(-)
> 
> diff --git a/drivers/net/ethernet/intel/ice/ice.h b/drivers/net/ethernet/intel/ice/ice.h
> index bea1d1e39fa2..717542e49d65 100644
> --- a/drivers/net/ethernet/intel/ice/ice.h
> +++ b/drivers/net/ethernet/intel/ice/ice.h
> @@ -300,7 +300,6 @@ enum ice_vsi_state {
>  	ICE_VSI_NETDEV_REGISTERED,
>  	ICE_VSI_UMAC_FLTR_CHANGED,
>  	ICE_VSI_MMAC_FLTR_CHANGED,
> -	ICE_VSI_VLAN_FLTR_CHANGED,
>  	ICE_VSI_PROMISC_CHANGED,
>  	ICE_VSI_STATE_NBITS		/* must be last */
>  };
> diff --git a/drivers/net/ethernet/intel/ice/ice_fltr.c b/drivers/net/ethernet/intel/ice/ice_fltr.c
> index c29177c6bb9d..8ed87b43a367 100644
> --- a/drivers/net/ethernet/intel/ice/ice_fltr.c
> +++ b/drivers/net/ethernet/intel/ice/ice_fltr.c
> @@ -58,7 +58,18 @@ int
>  ice_fltr_set_vlan_vsi_promisc(struct ice_hw *hw, struct ice_vsi *vsi,
>  			      u8 promisc_mask)
>  {
> -	return ice_set_vlan_vsi_promisc(hw, vsi->idx, promisc_mask, false);
> +	struct ice_pf *pf = hw->back;
> +	int result;
> +
> +	result = ice_set_vlan_vsi_promisc(hw, vsi->idx, promisc_mask, false);
> +	if (!result)
> +		return result;
> +
> +	dev_err(ice_pf_to_dev(pf),
> +		"Error setting promisc mode on VSI %i (rc=%d)\n", vsi->vsi_num,
> +		result);
> +

Our typical style here would be to do:

result = <function>;
if (result) {
	dev_err(...);
}

I find that much more readable than "if (!result) return;

> +	return result;
>  }
>  
>  /**
> @@ -73,7 +84,18 @@ int
>  ice_fltr_clear_vlan_vsi_promisc(struct ice_hw *hw, struct ice_vsi *vsi,
>  				u8 promisc_mask)
>  {
> -	return ice_set_vlan_vsi_promisc(hw, vsi->idx, promisc_mask, true);
> +	struct ice_pf *pf = hw->back;
> +	int result;
> +
> +	result = ice_set_vlan_vsi_promisc(hw, vsi->idx, promisc_mask, true);
> +	if (!result)
> +		return result;
> +
> +	dev_err(ice_pf_to_dev(pf),
> +		"Error clearing promisc mode on VSI %i (rc=%d)\n",
> +		vsi->vsi_num, result);
> +
> +	return result;
>  }
>  
>  /**
> @@ -87,7 +109,18 @@ int
>  ice_fltr_clear_vsi_promisc(struct ice_hw *hw, u16 vsi_handle, u8 promisc_mask,
>  			   u16 vid)
>  {
> -	return ice_clear_vsi_promisc(hw, vsi_handle, promisc_mask, vid);
> +	struct ice_pf *pf = hw->back;
> +	int result;
> +
> +	result = ice_clear_vsi_promisc(hw, vsi_handle, promisc_mask, vid);
> +	if (!result)
> +		return result;
> +
> +	dev_err(ice_pf_to_dev(pf),
> +		"Error clearing promisc mode on VSI %i for VID %u (rc=%d)\n",
> +		ice_get_hw_vsi_num(hw, vsi_handle), vid, result);
> +
> +	return result;
>  }
>  
>  /**
> @@ -101,7 +134,18 @@ int
>  ice_fltr_set_vsi_promisc(struct ice_hw *hw, u16 vsi_handle, u8 promisc_mask,
>  			 u16 vid)
>  {
> -	return ice_set_vsi_promisc(hw, vsi_handle, promisc_mask, vid);
> +	struct ice_pf *pf = hw->back;
> +	int result;
> +
> +	result = ice_set_vsi_promisc(hw, vsi_handle, promisc_mask, vid);
> +	if (!result)
> +		return result;
> +
> +	dev_err(ice_pf_to_dev(pf),
> +		"Error setting promisc mode on VSI %i for VID %u (rc=%d)\n",
> +		ice_get_hw_vsi_num(hw, vsi_handle), vid, result);
> +
> +	return result;
>  }
>  
>  /**
> diff --git a/drivers/net/ethernet/intel/ice/ice_main.c b/drivers/net/ethernet/intel/ice/ice_main.c
> index b7e8744b0c0a..168a41ea37b8 100644
> --- a/drivers/net/ethernet/intel/ice/ice_main.c
> +++ b/drivers/net/ethernet/intel/ice/ice_main.c
> @@ -227,8 +227,7 @@ static int ice_add_mac_to_unsync_list(struct net_device *netdev, const u8 *addr)
>  static bool ice_vsi_fltr_changed(struct ice_vsi *vsi)
>  {
>  	return test_bit(ICE_VSI_UMAC_FLTR_CHANGED, vsi->state) ||
> -	       test_bit(ICE_VSI_MMAC_FLTR_CHANGED, vsi->state) ||
> -	       test_bit(ICE_VSI_VLAN_FLTR_CHANGED, vsi->state);
> +	       test_bit(ICE_VSI_MMAC_FLTR_CHANGED, vsi->state);

Ok, so we now handle VLAN filters seprately without these states.

>  }
>  
>  /**
> @@ -244,10 +243,15 @@ static int ice_set_promisc(struct ice_vsi *vsi, u8 promisc_m)
>  	if (vsi->type != ICE_VSI_PF)
>  		return 0;
>  
> -	if (vsi->num_vlan > 1)
> -		status = ice_fltr_set_vlan_vsi_promisc(&vsi->back->hw, vsi, promisc_m);
> -	else
> -		status = ice_fltr_set_vsi_promisc(&vsi->back->hw, vsi->idx, promisc_m, 0);
> +	if (vsi->num_vlan > 1) {
> +		promisc_m |= (ICE_PROMISC_VLAN_RX | ICE_PROMISC_VLAN_TX);
> +		status = ice_fltr_set_vlan_vsi_promisc(&vsi->back->hw, vsi,
> +						       promisc_m);

Ok so if we're in >1 filter, we add the VLAN_RX and VLAN_TX flags. Right.

And we know that changes only from another ndo op to add VLANs?

> +	} else {
> +		status = ice_fltr_set_vsi_promisc(&vsi->back->hw, vsi->idx,
> +						  promisc_m, 0);
> +	}
> +
>  	return status;
>  }
>  
> @@ -264,10 +268,15 @@ static int ice_clear_promisc(struct ice_vsi *vsi, u8 promisc_m)
>  	if (vsi->type != ICE_VSI_PF)
>  		return 0;
>  
> -	if (vsi->num_vlan > 1)
> -		status = ice_fltr_clear_vlan_vsi_promisc(&vsi->back->hw, vsi, promisc_m);
> -	else
> -		status = ice_fltr_clear_vsi_promisc(&vsi->back->hw, vsi->idx, promisc_m, 0);
> +	if (vsi->num_vlan > 1) {
> +		promisc_m |= (ICE_PROMISC_VLAN_RX | ICE_PROMISC_VLAN_TX);
> +		status = ice_fltr_clear_vlan_vsi_promisc(&vsi->back->hw, vsi,
> +							 promisc_m);
> +	} else {
> +		status = ice_fltr_clear_vsi_promisc(&vsi->back->hw, vsi->idx,
> +						    promisc_m, 0);
> +	}
> +
>  	return status;
>  }
>  
> @@ -285,7 +294,6 @@ static int ice_vsi_sync_fltr(struct ice_vsi *vsi)
>  	struct ice_pf *pf = vsi->back;
>  	struct ice_hw *hw = &pf->hw;
>  	u32 changed_flags = 0;
> -	u8 promisc_m;
>  	int err;
>  
>  	if (!vsi->netdev)
> @@ -303,7 +311,6 @@ static int ice_vsi_sync_fltr(struct ice_vsi *vsi)
>  	if (ice_vsi_fltr_changed(vsi)) {
>  		clear_bit(ICE_VSI_UMAC_FLTR_CHANGED, vsi->state);
>  		clear_bit(ICE_VSI_MMAC_FLTR_CHANGED, vsi->state);
> -		clear_bit(ICE_VSI_VLAN_FLTR_CHANGED, vsi->state);
>  
>  		/* grab the netdev's addr_list_lock */
>  		netif_addr_lock_bh(netdev);
> @@ -352,29 +359,15 @@ static int ice_vsi_sync_fltr(struct ice_vsi *vsi)
>  	/* check for changes in promiscuous modes */
>  	if (changed_flags & IFF_ALLMULTI) {
>  		if (vsi->current_netdev_flags & IFF_ALLMULTI) {
> -			if (vsi->num_vlan > 1)
> -				promisc_m = ICE_MCAST_VLAN_PROMISC_BITS;
> -			else
> -				promisc_m = ICE_MCAST_PROMISC_BITS;
> -
> -			err = ice_set_promisc(vsi, promisc_m);
> +			err = ice_set_promisc(vsi, ICE_MCAST_PROMISC_BITS);
>  			if (err) {
> -				netdev_err(netdev, "Error setting Multicast promiscuous mode on VSI %i\n",
> -					   vsi->vsi_num);
>  				vsi->current_netdev_flags &= ~IFF_ALLMULTI;
>  				goto out_promisc;
>  			}
>  		} else {
>  			/* !(vsi->current_netdev_flags & IFF_ALLMULTI) */
> -			if (vsi->num_vlan > 1)
> -				promisc_m = ICE_MCAST_VLAN_PROMISC_BITS;
> -			else
> -				promisc_m = ICE_MCAST_PROMISC_BITS;
> -
> -			err = ice_clear_promisc(vsi, promisc_m);
> +			err = ice_clear_promisc(vsi, ICE_MCAST_PROMISC_BITS);
>  			if (err) {
> -				netdev_err(netdev, "Error clearing Multicast promiscuous mode on VSI %i\n",
> -					   vsi->vsi_num);
>  				vsi->current_netdev_flags |= IFF_ALLMULTI;
>  				goto out_promisc;
>  			}
> @@ -3445,19 +3438,47 @@ ice_vlan_rx_add_vid(struct net_device *netdev, __always_unused __be16 proto,
>  	if (!vid)
>  		return 0;
>  
> +	while (test_and_set_bit(ICE_CFG_BUSY, vsi->state))
> +		usleep_range(1000, 2000);
> +

Not your fault, but every time I see this I think about why not just
making this a mutex...

>  	/* Enable VLAN pruning when a VLAN other than 0 is added */
>  	if (!ice_vsi_is_vlan_pruning_ena(vsi)) {
>  		ret = ice_cfg_vlan_pruning(vsi, true);
>  		if (ret)
> -			return ret;
> +			goto finish;
> +	}
> +
> +	/* Add multicast promisc rule for the VLAN ID to be added if
> +	 * all-multicast is currently enabled.
> +	 */
> +	if (vsi->current_netdev_flags & IFF_ALLMULTI) {
> +		ret = ice_fltr_set_vsi_promisc(&vsi->back->hw, vsi->idx,
> +					       ICE_MCAST_VLAN_PROMISC_BITS,
> +					       vid);
> +		if (ret)
> +			goto finish;
>  	}

If we're not in multicast mode (or if multicast mode gets disabled) when
do we clear these bits?

I would have expected some sort of loop to iterate over VLANs?


>  
>  	/* Add a switch rule for this VLAN ID so its corresponding VLAN tagged
>  	 * packets aren't pruned by the device's internal switch on Rx
>  	 */
>  	ret = ice_vsi_add_vlan(vsi, vid, ICE_FWD_TO_VSI);
> -	if (!ret)
> -		set_bit(ICE_VSI_VLAN_FLTR_CHANGED, vsi->state);
> +	if (ret)
> +		goto finish;
> +
> +	/* If all-multicast is currently enabled and this VLAN ID is only one
> +	 * besides VLAN-0 we have to update look-up type of multicast promisc
> +	 * rule for VLAN-0 from ICE_SW_LKUP_PROMISC to ICE_SW_LKUP_PROMISC_VLAN.
> +	 */
> +	if ((vsi->current_netdev_flags & IFF_ALLMULTI) && vsi->num_vlan == 2) {
> +		ice_fltr_clear_vsi_promisc(&vsi->back->hw, vsi->idx,
> +					   ICE_MCAST_PROMISC_BITS, 0);
> +		ice_fltr_set_vsi_promisc(&vsi->back->hw, vsi->idx,
> +					 ICE_MCAST_VLAN_PROMISC_BITS, 0);
> +	}
> +
> +finish:
> +	clear_bit(ICE_CFG_BUSY, vsi->state);
>  
>  	return ret;
>  }
> @@ -3482,18 +3503,44 @@ ice_vlan_rx_kill_vid(struct net_device *netdev, __always_unused __be16 proto,
>  	if (!vid)
>  		return 0;
>  
> +	while (test_and_set_bit(ICE_CFG_BUSY, vsi->state))
> +		usleep_range(1000, 2000);
> +
>  	/* Make sure ice_vsi_kill_vlan is successful before updating VLAN
>  	 * information
>  	 */
>  	ret = ice_vsi_kill_vlan(vsi, vid);
>  	if (ret)
> -		return ret;
> +		goto finish;
>  
> -	/* Disable pruning when VLAN 0 is the only VLAN rule */
> -	if (vsi->num_vlan == 1 && ice_vsi_is_vlan_pruning_ena(vsi))
> -		ret = ice_cfg_vlan_pruning(vsi, false);
> +	/* Remove multicast promisc rule for the removed VLAN ID if
> +	 * all-multicast is enabled.
> +	 */
> +	if (vsi->current_netdev_flags & IFF_ALLMULTI)
> +		ice_fltr_clear_vsi_promisc(&vsi->back->hw, vsi->idx,
> +					   ICE_MCAST_VLAN_PROMISC_BITS, vid);
> +
> +	if (vsi->num_vlan == 1) {
> +		/* Disable pruning when VLAN 0 is the only VLAN rule */
> +		if (ice_vsi_is_vlan_pruning_ena(vsi))
> +			ice_cfg_vlan_pruning(vsi, false);
> +
> +		/* Update look-up type of multicast promisc rule for VLAN 0
> +		 * from ICE_SW_LKUP_PROMISC_VLAN to ICE_SW_LKUP_PROMISC when
> +		 * all-multicast is enabled and VLAN 0 is the only VLAN rule.
> +		 */
> +		if (vsi->current_netdev_flags & IFF_ALLMULTI) {
> +			ice_fltr_clear_vsi_promisc(&vsi->back->hw, vsi->idx,
> +						   ICE_MCAST_VLAN_PROMISC_BITS,
> +						   0);
> +			ice_fltr_set_vsi_promisc(&vsi->back->hw, vsi->idx,
> +						 ICE_MCAST_PROMISC_BITS, 0);
> +		}
> +	}
> +
> +finish:
> +	clear_bit(ICE_CFG_BUSY, vsi->state);
>  
> -	set_bit(ICE_VSI_VLAN_FLTR_CHANGED, vsi->state);
>  	return ret;
>  }
>