[PATCH v2 2/4] dma/idxd: fix paths to driver sysfs directory

[Bruce Richardson]

Recent kernel changes[1][2] mean that we cannot guarantee that the paths
in sysfs used for creating/binding a DSA or workqueue instance will be
as given in the utility script, since they are now "compatibility-mode
only". Update script to support both new paths and compatibility ones.

[1] https://lore.kernel.org/all/162637445139.744545.6008938867943724701.stgit@djiang5-desk3.ch.intel.com/
[2] https://lore.kernel.org/all/162637468705.744545.4399080971745974435.stgit@djiang5-desk3.ch.intel.com/

Fixes: 01863b9d2354 ("raw/ioat: include example configuration script")
Cc: stable at dpdk.org

Signed-off-by: Bruce Richardson <bruce.richardson at intel.com>
---
 drivers/dma/idxd/dpdk_idxd_cfg.py | 18 ++++++++++++++----
 1 file changed, 14 insertions(+), 4 deletions(-)

diff --git a/drivers/dma/idxd/dpdk_idxd_cfg.py b/drivers/dma/idxd/dpdk_idxd_cfg.py
index fcc27822ef..34537cb980 100755
--- a/drivers/dma/idxd/dpdk_idxd_cfg.py
+++ b/drivers/dma/idxd/dpdk_idxd_cfg.py
@@ -29,9 +29,17 @@ def write_values(self, values):
                 f.write(str(contents))
 
 
+def get_drv_dir(dtype):
+    "Get the sysfs path for the driver, either 'idxd' or 'user'"
+    drv_dir = "/sys/bus/dsa/drivers/" + dtype
+    if not os.path.exists(drv_dir):
+        return "/sys/bus/dsa/drivers/dsa"
+    return drv_dir
+
+
 def reset_device(dsa_id):
     "Reset the DSA device and all its queues"
-    drv_dir = SysfsDir("/sys/bus/dsa/drivers/dsa")
+    drv_dir = SysfsDir(get_drv_dir("idxd"))
     drv_dir.write_values({"unbind": f"dsa{dsa_id}"})
 
 
@@ -58,7 +66,6 @@ def get_dsa_id(pci):
 def configure_dsa(dsa_id, queues, prefix):
     "Configure the DSA instance with appropriate number of queues"
     dsa_dir = SysfsDir(f"/sys/bus/dsa/devices/dsa{dsa_id}")
-    drv_dir = SysfsDir("/sys/bus/dsa/drivers/dsa")
 
     max_groups = dsa_dir.read_int("max_groups")
     max_engines = dsa_dir.read_int("max_engines")
@@ -85,9 +92,12 @@ def configure_dsa(dsa_id, queues, prefix):
                              "size": int(max_work_queues_size / nb_queues)})
 
     # enable device and then queues
-    drv_dir.write_values({"bind": f"dsa{dsa_id}"})
+    idxd_dir = SysfsDir(get_drv_dir("idxd"))
+    idxd_dir.write_values({"bind": f"dsa{dsa_id}"})
+
+    user_dir = SysfsDir(get_drv_dir("user"))
     for q in range(nb_queues):
-        drv_dir.write_values({"bind": f"wq{dsa_id}.{q}"})
+        user_dir.write_values({"bind": f"wq{dsa_id}.{q}"})
 
 
 def main(args):
-- 
2.32.0