i40e: Fix issue when maximum queues is exceeded

Before this patch VF interface vanished when
maximum queue number was exceeded. Driver tried
to add next queues even if there was not enough
space. PF sent incorrect number of queues to
the VF when there were not enough of them.

Add an additional condition introduced to check
available space in 'qp_pile' before proceeding.
This condition makes it impossible to add queues
if they number is greater than the number resulting
from available space.
Also add the search for free space in PF queue
pair piles.

Without this patch VF interfaces are not seen
when available space for queues has been
exceeded and following logs appears permanently
in dmesg:
"Unable to get VF config (-32)".
"VF 62 failed opcode 3, retval: -5"
"Unable to get VF config due to PF error condition, not retrying"

Fixes: 7daa6bf3294e ("i40e: driver core headers")
Fixes: 41c445ff0f48 ("i40e: main driver core")
Signed-off-by: Jaroslaw Gawin <jaroslawx.gawin@intel.com>
Signed-off-by: Slawomir Laba <slawomirx.laba@intel.com>
Signed-off-by: Jedrzej Jagielski <jedrzej.jagielski@intel.com>
Tested-by: Konrad Jankowski <konrad0.jankowski@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

1 files changed, 59 insertions, 0 deletions

diff --git a/drivers/net/ethernet/intel/i40e/i40e_virtchnl_pf.c b/drivers/net/ethernet/intel/i40e/i40e_virtchnl_pf.c
index b785d09c19f8..7dd2a2bab339 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_virtchnl_pf.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_virtchnl_pf.c
@@ -2618,6 +2618,59 @@ error_param:
 }
 
 /**
+ * i40e_check_enough_queue - find big enough queue number
+ * @vf: pointer to the VF info
+ * @needed: the number of items needed
+ *
+ * Returns the base item index of the queue, or negative for error
+ **/
+static int i40e_check_enough_queue(struct i40e_vf *vf, u16 needed)
+{
+	unsigned int  i, cur_queues, more, pool_size;
+	struct i40e_lump_tracking *pile;
+	struct i40e_pf *pf = vf->pf;
+	struct i40e_vsi *vsi;
+
+	vsi = pf->vsi[vf->lan_vsi_idx];
+	cur_queues = vsi->alloc_queue_pairs;
+
+	/* if current allocated queues are enough for need */
+	if (cur_queues >= needed)
+		return vsi->base_queue;
+
+	pile = pf->qp_pile;
+	if (cur_queues > 0) {
+		/* if the allocated queues are not zero
+		 * just check if there are enough queues for more
+		 * behind the allocated queues.
+		 */
+		more = needed - cur_queues;
+		for (i = vsi->base_queue + cur_queues;
+			i < pile->num_entries; i++) {
+			if (pile->list[i] & I40E_PILE_VALID_BIT)
+				break;
+
+			if (more-- == 1)
+				/* there is enough */
+				return vsi->base_queue;
+		}
+	}
+
+	pool_size = 0;
+	for (i = 0; i < pile->num_entries; i++) {
+		if (pile->list[i] & I40E_PILE_VALID_BIT) {
+			pool_size = 0;
+			continue;
+		}
+		if (needed <= ++pool_size)
+			/* there is enough */
+			return i;
+	}
+
+	return -ENOMEM;
+}
+
+/**
  * i40e_vc_request_queues_msg
  * @vf: pointer to the VF info
  * @msg: pointer to the msg buffer
@@ -2651,6 +2704,12 @@ static int i40e_vc_request_queues_msg(struct i40e_vf *vf, u8 *msg)
 			 req_pairs - cur_pairs,
 			 pf->queues_left);
 		vfres->num_queue_pairs = pf->queues_left + cur_pairs;
+	} else if (i40e_check_enough_queue(vf, req_pairs) < 0) {
+		dev_warn(&pf->pdev->dev,
+			 "VF %d requested %d more queues, but there is not enough for it.\n",
+			 vf->vf_id,
+			 req_pairs - cur_pairs);
+		vfres->num_queue_pairs = cur_pairs;
 	} else {
 		/* successful request */
 		vf->num_req_queues = req_pairs;