[PATCH net-next 3/3] selftests: drv-net: iou-zcrx: allocate hugepages for large chunks test

[Jakub Kicinski <kuba@kernel.org>]

The large chunks test needs 2MB hugepages for its mmap allocation,
but the test system may not have any pre-allocated. Ensure at least
64 hugepages are available before running the test, and restore the
original value on cleanup.

While at it strip the stdout, it has a trailing new line.

Before:
  ok 5 iou-zcrx.test_zcrx_large_chunks # SKIP Can't allocate huge pages

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---
CC: shuah@kernel.org
CC: dw@davidwei.uk
CC: jdamato@fastly.com
CC: linux-kselftest@vger.kernel.org
---
 tools/testing/selftests/drivers/net/hw/iou-zcrx.py | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/drivers/net/hw/iou-zcrx.py b/tools/testing/selftests/drivers/net/hw/iou-zcrx.py
index 1649c23e05e2..66dd496ec5cf 100755
--- a/tools/testing/selftests/drivers/net/hw/iou-zcrx.py
+++ b/tools/testing/selftests/drivers/net/hw/iou-zcrx.py
@@ -135,13 +135,21 @@ SKIP_CODE = 42
 
     cfg.require_ipver('6')
 
+    hp_file = "/proc/sys/vm/nr_hugepages"
+    with open(hp_file, 'r+', encoding='utf-8') as f:
+        nr_hugepages = int(f.read().strip())
+        if nr_hugepages < 64:
+            f.seek(0)
+            f.write("64")
+            defer(lambda: open(hp_file, 'w', encoding='utf-8').write(str(nr_hugepages)))
+
     single(cfg)
     rx_cmd = f"{cfg.bin_local} -s -p {cfg.port} -i {cfg.ifname} -q {cfg.target} -x 2"
     tx_cmd = f"{cfg.bin_remote} -c -h {cfg.addr_v['6']} -p {cfg.port} -l 12840"
 
     probe = cmd(rx_cmd + " -d", fail=False)
     if probe.ret == SKIP_CODE:
-        raise KsftSkipEx(probe.stdout)
+        raise KsftSkipEx(probe.stdout.strip())
 
     with bkg(rx_cmd, exit_wait=True):
         wait_port_listen(cfg.port, proto="tcp")
-- 
2.53.0