Patch "i40e: improve locking of mac_filter_hash" has been added to the 5.4-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    i40e: improve locking of mac_filter_hash

to the 5.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     i40e-improve-locking-of-mac_filter_hash.patch
and it can be found in the queue-5.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 47d4b0c7e3901cd66744a24f5ba7f0a2cec86a68
Author: Stefan Assmann <sassmann@xxxxxxxxx>
Date:   Thu Mar 4 10:34:30 2021 +0100

    i40e: improve locking of mac_filter_hash
    
    [ Upstream commit 8b4b06919fd66caf49fdf4fe59f9d6312cf7956d ]
    
    i40e_config_vf_promiscuous_mode() calls
    i40e_getnum_vf_vsi_vlan_filters() without acquiring the
    mac_filter_hash_lock spinlock.
    
    This is unsafe because mac_filter_hash may get altered in another thread
    while i40e_getnum_vf_vsi_vlan_filters() traverses the hashes.
    
    Simply adding the spinlock in i40e_getnum_vf_vsi_vlan_filters() is not
    possible as it already gets called in i40e_get_vlan_list_sync() with the
    spinlock held. Therefore adding a wrapper that acquires the spinlock and
    call the correct function where appropriate.
    
    Fixes: 37d318d7805f ("i40e: Remove scheduling while atomic possibility")
    Fix-suggested-by: Paolo Abeni <pabeni@xxxxxxxxxx>
    Signed-off-by: Stefan Assmann <sassmann@xxxxxxxxx>
    Tested-by: Konrad Jankowski <konrad0.jankowski@xxxxxxxxx>
    Signed-off-by: Tony Nguyen <anthony.l.nguyen@xxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/net/ethernet/intel/i40e/i40e_virtchnl_pf.c b/drivers/net/ethernet/intel/i40e/i40e_virtchnl_pf.c
index 1a3017e5f44c1..291ee55b125f8 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_virtchnl_pf.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_virtchnl_pf.c
@@ -1117,12 +1117,12 @@ static int i40e_quiesce_vf_pci(struct i40e_vf *vf)
 }
 
 /**
- * i40e_getnum_vf_vsi_vlan_filters
+ * __i40e_getnum_vf_vsi_vlan_filters
  * @vsi: pointer to the vsi
  *
  * called to get the number of VLANs offloaded on this VF
  **/
-static int i40e_getnum_vf_vsi_vlan_filters(struct i40e_vsi *vsi)
+static int __i40e_getnum_vf_vsi_vlan_filters(struct i40e_vsi *vsi)
 {
 	struct i40e_mac_filter *f;
 	int num_vlans = 0, bkt;
@@ -1135,6 +1135,23 @@ static int i40e_getnum_vf_vsi_vlan_filters(struct i40e_vsi *vsi)
 	return num_vlans;
 }
 
+/**
+ * i40e_getnum_vf_vsi_vlan_filters
+ * @vsi: pointer to the vsi
+ *
+ * wrapper for __i40e_getnum_vf_vsi_vlan_filters() with spinlock held
+ **/
+static int i40e_getnum_vf_vsi_vlan_filters(struct i40e_vsi *vsi)
+{
+	int num_vlans;
+
+	spin_lock_bh(&vsi->mac_filter_hash_lock);
+	num_vlans = __i40e_getnum_vf_vsi_vlan_filters(vsi);
+	spin_unlock_bh(&vsi->mac_filter_hash_lock);
+
+	return num_vlans;
+}
+
 /**
  * i40e_get_vlan_list_sync
  * @vsi: pointer to the VSI
@@ -1152,7 +1169,7 @@ static void i40e_get_vlan_list_sync(struct i40e_vsi *vsi, int *num_vlans,
 	int bkt;
 
 	spin_lock_bh(&vsi->mac_filter_hash_lock);
-	*num_vlans = i40e_getnum_vf_vsi_vlan_filters(vsi);
+	*num_vlans = __i40e_getnum_vf_vsi_vlan_filters(vsi);
 	*vlan_list = kcalloc(*num_vlans, sizeof(**vlan_list), GFP_ATOMIC);
 	if (!(*vlan_list))
 		goto err;