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Commit cbebb85f authored by Jacob Keller's avatar Jacob Keller Committed by Jeff Kirsher
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i40e: avoid looping to check whether we're in VLAN mode 



We determine that a VSI is in vlan_mode whenever it has any filters
with a VLAN other than -1 (I40E_VLAN_ALL). The previous method of doing
so was to perform a loop whenever we needed the check. However, we can
notice that only place where filters are added (i40e_add_filter) can
change the condition from false to true, and the only place we can
return to false is in i40e_vsi_sync_filters_subtask. Thus, we can remove
the loop and use a boolean directly.

Doing this avoids looping over filters repeatedly especially while we're
already inside a loop over all the filters. This should reduce the
latency of filter operations throughout the driver.

Change-ID: Iafde08df588da2a2ea666997d05e11fad8edc338
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 84f5ca6c

drivers/net/ethernet/intel/i40e/i40e.h

+1 −0
Original line number Diff line number Diff line
@@ -517,6 +517,7 @@ struct i40e_vsi { 
	spinlock_t mac_filter_hash_lock;

	/* Fixed size hash table with 2^8 buckets for MAC filters */

	DECLARE_HASHTABLE(mac_filter_hash, 8);

	bool has_vlan_filter;



	/* VSI stats */

	struct rtnl_link_stats64 net_stats;

drivers/net/ethernet/intel/i40e/i40e_main.c

+37 −11
Original line number Diff line number Diff line
@@ -1198,19 +1198,31 @@ struct i40e_mac_filter *i40e_find_mac(struct i40e_vsi *vsi, const u8 *macaddr) 
 **/

bool i40e_is_vsi_in_vlan(struct i40e_vsi *vsi)

{

	struct i40e_mac_filter *f;

	struct hlist_node *h;

	int bkt;



	/* Only -1 for all the filters denotes not in vlan mode

	 * so we have to go through all the list in order to make sure

	 */

	hash_for_each_safe(vsi->mac_filter_hash, bkt, h, f, hlist) {

		if (f->vlan >= 0 || vsi->info.pvid)

	/* If we have a PVID, always operate in VLAN mode */

	if (vsi->info.pvid)

		return true;

	}



	return false;

	/* We need to operate in VLAN mode whenever we have any filters with

	 * a VLAN other than I40E_VLAN_ALL. We could check the table each

	 * time, incurring search cost repeatedly. However, we can notice two

	 * things:

	 *

	 * 1) the only place where we can gain a VLAN filter is in

	 *    i40e_add_filter.

	 *

	 * 2) the only place where filters are actually removed is in

	 *    i40e_vsi_sync_filters_subtask.

	 *

	 * Thus, we can simply use a boolean value, has_vlan_filters which we

	 * will set to true when we add a VLAN filter in i40e_add_filter. Then

	 * we have to perform the full search after deleting filters in

	 * i40e_vsi_sync_filters_subtask, but we already have to search

	 * filters here and can perform the check at the same time. This

	 * results in avoiding embedding a loop for VLAN mode inside another

	 * loop over all the filters, and should maintain correctness as noted

	 * above.

	 */

	return vsi->has_vlan_filter;

}



/**
@@ -1246,6 +1258,12 @@ struct i40e_mac_filter *i40e_add_filter(struct i40e_vsi *vsi, 
		if (!f)

			return NULL;



		/* Update the boolean indicating if we need to function in

		 * VLAN mode.

		 */

		if (vlan >= 0)

			vsi->has_vlan_filter = true;



		ether_addr_copy(f->macaddr, macaddr);

		f->vlan = vlan;

		/* If we're in overflow promisc mode, set the state directly
@@ -1979,6 +1997,14 @@ int i40e_sync_vsi_filters(struct i40e_vsi *vsi) 
		del_list = NULL;

	}



	/* After finishing notifying firmware of the deleted filters, update

	 * the cached value of vsi->has_vlan_filter. Note that we are safe to

	 * use just !!vlan_filters here because if we only have VLAN=0 (that

	 * is, non_vlan_filters) these will all be converted to VLAN=-1 in the

	 * logic above already so this value would still be correct.

	 */

	vsi->has_vlan_filter = !!vlan_filters;



	if (!hlist_empty(&tmp_add_list)) {

		/* Do all the adds now. */

		filter_list_len = hw->aq.asq_buf_size /