[PATCH net-next 2/6] selftests: drv-net: extract _find_bss_map_id helper in NetDrvContEnv

From
Bobby Eshleman <hidden>
Date
2026-03-16 22:29:23
Also in
bpf, linux-kselftest, lkml
Reply to
Bobby Eshleman, 2026-03-16
From: Bobby Eshleman <bobbyeshleman@meta.com>

Factor out a _find_bss_map_id() helper from _attach_bpf() so it can be
reused by other BPF attachment methods. This will be used by subsequent
patches in this series that add support for netkit devmem TX testing.

No functional change to existing tests.

Signed-off-by: Bobby Eshleman <bobbyeshleman@meta.com>
---
 tools/testing/selftests/drivers/net/lib/py/env.py | 21 ++++++++++-----------
 1 file changed, 10 insertions(+), 11 deletions(-)
diff --git a/tools/testing/selftests/drivers/net/lib/py/env.py b/tools/testing/selftests/drivers/net/lib/py/env.py
index ccff345fe1c1..08e90448f48d 100644
--- a/tools/testing/selftests/drivers/net/lib/py/env.py
+++ b/tools/testing/selftests/drivers/net/lib/py/env.py
@@ -467,6 +467,15 @@ class NetDrvContEnv(NetDrvEpEnv):
                 return (bpf['pref'], bpf['options']['prog']['id'])
         raise Exception("Failed to get BPF prog ID")
 
+    def _find_bss_map_id(self, prog_id):
+        """Find the .bss map ID for a loaded BPF program."""
+        prog_info = bpftool(f"prog show id {prog_id}", json=True)
+        for map_id in prog_info.get("map_ids", []):
+            map_info = bpftool(f"map show id {map_id}", json=True)
+            if map_info.get("name", "").endswith("bss"):
+                return map_id
+        raise Exception(f"Failed to find .bss map for prog {prog_id}")
+
     def _attach_bpf(self):
         bpf_obj = self.test_dir / "nk_forward.bpf.o"
         if not bpf_obj.exists():
@@ -478,17 +487,7 @@ class NetDrvContEnv(NetDrvEpEnv):
         self._tc_attached = True
 
         (self._bpf_prog_pref, self._bpf_prog_id) = self._get_bpf_prog_ids()
-        prog_info = bpftool(f"prog show id {self._bpf_prog_id}", json=True)
-        map_ids = prog_info.get("map_ids", [])
-
-        bss_map_id = None
-        for map_id in map_ids:
-            map_info = bpftool(f"map show id {map_id}", json=True)
-            if map_info.get("name").endswith("bss"):
-                bss_map_id = map_id
-
-        if bss_map_id is None:
-            raise Exception("Failed to find .bss map")
+        bss_map_id = self._find_bss_map_id(self._bpf_prog_id)
 
         ipv6_addr = ipaddress.IPv6Address(self.ipv6_prefix)
         ipv6_bytes = ipv6_addr.packed
-- 
2.52.0
Thread (13 messages) 13 messages, 3 authors, last reply 2026-03-19
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