raw/ioat: fix script for configuring small number of queues

The dpdk_idxd_cfg.py script included with the driver for convenience did
not work properly where the number of queues to be configured was
less than the number of groups or engines. This was because there would
be configured groups/engines not assigned to queues. Fix this by
limiting the engine and group counts to be no bigger than the number of
queues.

Fixes: 01863b9d2354 ("raw/ioat: include example configuration script")
Cc: stable@dpdk.org
Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>

diff --git a/drivers/raw/ioat/dpdk_idxd_cfg.py b/drivers/raw/ioat/dpdk_idxd_cfg.py
index bce4bb5..56e4406 100755 (executable)
--- a/drivers/raw/ioat/dpdk_idxd_cfg.py
+++ b/drivers/raw/ioat/dpdk_idxd_cfg.py
@@ -39,15 +39,15 @@ def configure_dsa(dsa_id, queues):
     max_queues = dsa_dir.read_int("max_work_queues")
     max_tokens = dsa_dir.read_int("max_tokens")
 
-    # we want one engine per group
-    nb_groups = min(max_engines, max_groups)
-    for grp in range(nb_groups):
-        dsa_dir.write_values({f"engine{dsa_id}.{grp}/group_id": grp})
-
     nb_queues = min(queues, max_queues)
     if queues > nb_queues:
         print(f"Setting number of queues to max supported value: {max_queues}")
 
+    # we want one engine per group, and no more engines than queues
+    nb_groups = min(max_engines, max_groups, nb_queues)
+    for grp in range(nb_groups):
+        dsa_dir.write_values({f"engine{dsa_id}.{grp}/group_id": grp})
+
     # configure each queue
     for q in range(nb_queues):
         wq_dir = SysfsDir(os.path.join(dsa_dir.path, f"wq{dsa_id}.{q}"))