Add a test that triggers the code touched by commit d0930bb8f46b ("blk-mq:
Fix a recently introduced regression in blk_mq_realloc_hw_ctxs()"). This
test only runs if a recently added fault injection feature is available,
namely commit 596444e75705 ("null_blk: Add support for init_hctx() fault
injection").
Cc: Ming Lei <ming.lei@xxxxxxxxxx>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@xxxxxxx>
Signed-off-by: Bart Van Assche <bvanassche@xxxxxxx>
---
tests/block/030 | 52 +++++++++++++++++++++++++++++++++++++++++++++
tests/block/030.out | 1 +
2 files changed, 53 insertions(+)
create mode 100755 tests/block/030
create mode 100644 tests/block/030.out
diff --git a/tests/block/030 b/tests/block/030
new file mode 100755
index 000000000000..2b159510e586
--- /dev/null
+++ b/tests/block/030
@@ -0,0 +1,52 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+# Copyright 2020 Google LLC
+#
+# Trigger the blk_mq_realloc_hw_ctxs() error path.
+
+. tests/block/rc
+. common/null_blk
+
+DESCRIPTION="trigger the blk_mq_realloc_hw_ctxs() error path"
+QUICK=1
+
+requires() {
+ _have_null_blk || return $?
+ _have_module_param null_blk init_hctx || return $?
+}
+
+test() {
+ local i sq=/sys/kernel/config/nullb/nullb0/submit_queues
+
+ : "${TIMEOUT:=30}"
+ # Legend: init_hctx=<interval>,<probability>,<space>,<times>
+ # Set <space> to $(nproc) + 1 to make loading of null_blk succeed.
+ if ! _init_null_blk nr_devices=0 queue_mode=2 \
+ "init_hctx=$(nproc),100,$(($(nproc)+1)),-1"; then
+ echo "Loading null_blk failed"
+ return 1
+ fi
+ if ! _configure_null_blk nullb0 completion_nsec=0 blocksize=512 size=16\
+ submit_queues="$(nproc)" memory_backed=1 power=1; then
+ echo "Configuring null_blk failed"
+ return 1
+ fi
+ # Since older null_blk versions do not allow "submit_queues" to be
+ # modified, check first whether that configs attribute is writeable.
+ # Each iteration of the loop below triggers $(nproc) + 1
+ # null_init_hctx() calls. Since <interval>=$(nproc), all possible
+ # blk_mq_realloc_hw_ctxs() error paths will be triggered. Whether or
+ # not this test succeeds depends on whether or not _check_dmesg()
+ # detects a kernel warning.
+ if { echo "$(<"$sq")" >$sq; } 2>/dev/null; then
+ for ((i=0;i<100;i++)); do
+ echo 1 >$sq
+ nproc >$sq
+ done
+ else
+ SKIP_REASON="Skipping test because $sq cannot be modified"
+ fi
+ rmdir /sys/kernel/config/nullb/nullb0
+ _exit_null_blk
+ echo Passed
+}
diff --git a/tests/block/030.out b/tests/block/030.out
new file mode 100644
index 000000000000..863339fb8ced
--- /dev/null
+++ b/tests/block/030.out
@@ -0,0 +1 @@
+Passed
