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Commit ba4e003d authored by Jacob Keller's avatar Jacob Keller Committed by Jeff Kirsher
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i40e: don't hold spinlock while resetting VF 



When we refactored handling of the PVID in commit 9af52f60
("i40e: use (add|rm)_vlan_all_mac helper functions when changing PVID")
we introduced a scheduling while atomic regression.

This occurred because we now held the spinlock across a call to
i40e_reset_vf(), which results in a usleep_range() call that triggers
a scheduling while atomic bug. This was rare as it only occurred if the
user configured a VLAN on a VF and also attempted to reconfigure the VF
from the host system with a port VLAN.

We do need to hold the lock while calling i40e_is_vsi_in_vlan(), but we
should not be holding it while we reset the VF.

We'll fix this by introducing a separate helper function
i40e_vsi_has_vlans which checks whether we have a PVID and whether the
VSI has configured VLANs. This helper function will manage its own need
for the mac_filter_hash_lock.

Then, we can move the acquiring of the spinlock until after we reset the
VF, which ensures that we do not sleep while holding the lock.

Using a separate function like this makes the code more clear and is
easier to read than attempting to release and re-acquire the spinlock
when we reset the VF.

Signed-off-by: default avatarJacob Keller <jacob.e.keller@intel.com>
Tested-by: default avatarAndrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: default avatarJeff Kirsher <jeffrey.t.kirsher@intel.com>
parent 00f6c2f5

drivers/net/ethernet/intel/i40e/i40e_virtchnl_pf.c

+32 −4
Original line number Diff line number Diff line
@@ -2925,6 +2925,34 @@ int i40e_ndo_set_vf_mac(struct net_device *netdev, int vf_id, u8 *mac) 
	return ret;

}



/**

 * i40e_vsi_has_vlans - True if VSI has configured VLANs

 * @vsi: pointer to the vsi

 *

 * Check if a VSI has configured any VLANs. False if we have a port VLAN or if

 * we have no configured VLANs. Do not call while holding the

 * mac_filter_hash_lock.

 */

static bool i40e_vsi_has_vlans(struct i40e_vsi *vsi)

{

	bool have_vlans;



	/* If we have a port VLAN, then the VSI cannot have any VLANs

	 * configured, as all MAC/VLAN filters will be assigned to the PVID.

	 */

	if (vsi->info.pvid)

		return false;



	/* Since we don't have a PVID, we know that if the device is in VLAN

	 * mode it must be because of a VLAN filter configured on this VSI.

	 */

	spin_lock_bh(&vsi->mac_filter_hash_lock);

	have_vlans = i40e_is_vsi_in_vlan(vsi);

	spin_unlock_bh(&vsi->mac_filter_hash_lock);



	return have_vlans;

}



/**

 * i40e_ndo_set_vf_port_vlan

 * @netdev: network interface device structure
@@ -2977,10 +3005,7 @@ int i40e_ndo_set_vf_port_vlan(struct net_device *netdev, int vf_id, 
		/* duplicate request, so just return success */

		goto error_pvid;



	/* Locked once because multiple functions below iterate list */

	spin_lock_bh(&vsi->mac_filter_hash_lock);



	if (le16_to_cpu(vsi->info.pvid) == 0 && i40e_is_vsi_in_vlan(vsi)) {

	if (i40e_vsi_has_vlans(vsi)) {

		dev_err(&pf->pdev->dev,

			"VF %d has already configured VLAN filters and the administrator is requesting a port VLAN override.\nPlease unload and reload the VF driver for this change to take effect.\n",

			vf_id);
@@ -2993,6 +3018,9 @@ int i40e_ndo_set_vf_port_vlan(struct net_device *netdev, int vf_id, 
		vsi = pf->vsi[vf->lan_vsi_idx];

	}



	/* Locked once because multiple functions below iterate list */

	spin_lock_bh(&vsi->mac_filter_hash_lock);



	/* Check for condition where there was already a port VLAN ID

	 * filter set and now it is being deleted by setting it to zero.

	 * Additionally check for the condition where there was a port