[dpdk-stable] [PATCH 17.11] net/enic: do not overwrite admin Tx queue limit

[Hyong Youb Kim]

[ backported from upstream commit 2a7e3d54659cd12d337ad816dcf202eec1af1367 ]

Currently, enic_alloc_wq (via rte_eth_tx_queue_setup) may overwrite
the admin limit with a lower value. This is wrong as seen in the
following sequence.

1. UCS admin-set Tx queue limit (config.wq_desc_count) = 4096
2. Set up tx queue with 512 descriptors
   The admin limit (config.wq_desc_count) becomes 512.
3. Stop ports and now set up Tx queue with 1024 descriptors.
   This fails because 1024 is greater than the admin limit (512).

Do not modify the admin limit, and when queried, report the current
number of descriptors instead of the admin limit. The rx queue setup
(enic_alloc_rq) does not this problem.

Fixes: fefed3d1e62c ("enic: new driver")

Signed-off-by: Hyong Youb Kim <hyonkim at cisco.com>
Reviewed-by: John Daley <johndale at cisco.com>
---
 drivers/net/enic/enic_main.c | 30 ++++++++++++++----------------
 1 file changed, 14 insertions(+), 16 deletions(-)

diff --git a/drivers/net/enic/enic_main.c b/drivers/net/enic/enic_main.c
index 6356c10cb..bf08dcadb 100644
--- a/drivers/net/enic/enic_main.c
+++ b/drivers/net/enic/enic_main.c
@@ -782,25 +782,23 @@ int enic_alloc_wq(struct enic *enic, uint16_t queue_idx,
 	static int instance;
 
 	wq->socket_id = socket_id;
-	if (nb_desc) {
-		if (nb_desc > enic->config.wq_desc_count) {
-			dev_warning(enic,
-				"WQ %d - number of tx desc in cmd line (%d)"\
-				"is greater than that in the UCSM/CIMC adapter"\
-				"policy.  Applying the value in the adapter "\
-				"policy (%d)\n",
-				queue_idx, nb_desc, enic->config.wq_desc_count);
-		} else if (nb_desc != enic->config.wq_desc_count) {
-			enic->config.wq_desc_count = nb_desc;
-			dev_info(enic,
-				"TX Queues - effective number of descs:%d\n",
-				nb_desc);
-		}
+	if (nb_desc > enic->config.wq_desc_count) {
+		dev_warning(enic,
+			    "WQ %d - number of tx desc in cmd line (%d) "
+			    "is greater than that in the UCSM/CIMC adapter "
+			    "policy.  Applying the value in the adapter "
+			    "policy (%d)\n",
+			    queue_idx, nb_desc, enic->config.wq_desc_count);
+		nb_desc = enic->config.wq_desc_count;
+	} else if (nb_desc != enic->config.wq_desc_count) {
+		dev_info(enic,
+			 "TX Queues - effective number of descs:%d\n",
+			 nb_desc);
 	}
 
 	/* Allocate queue resources */
 	err = vnic_wq_alloc(enic->vdev, &enic->wq[queue_idx], queue_idx,
-		enic->config.wq_desc_count,
+		nb_desc,
 		sizeof(struct wq_enet_desc));
 	if (err) {
 		dev_err(enic, "error in allocation of wq\n");
@@ -808,7 +806,7 @@ int enic_alloc_wq(struct enic *enic, uint16_t queue_idx,
 	}
 
 	err = vnic_cq_alloc(enic->vdev, &enic->cq[cq_index], cq_index,
-		socket_id, enic->config.wq_desc_count,
+		socket_id, nb_desc,
 		sizeof(struct cq_enet_wq_desc));
 	if (err) {
 		vnic_wq_free(wq);
-- 
2.16.2