selftests: ublk: add _ublk_sleep helper for parallel execution

Add _ublk_sleep() helper function that uses different sleep times
depending on whether tests run in parallel or sequential mode.

Usage: _ublk_sleep <normal_secs> <parallel_secs>

Export JOBS variable from Makefile so test scripts can detect parallel
execution, and use _ublk_sleep in test_part_02.sh to handle the
partition scan delay (1s normal, 5s parallel).

Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

tools/testing/selftests/ublk/Makefile

@@ -78,6 +78,7 @@ check:
 # JOBS>1: parallel execution with xargs -P
 # Usage: make run_null JOBS=4
 JOBS ?= 1
+export JOBS
 
 # Auto-detect test groups from TEST_PROGS (test_<group>_<num>.sh -> group)
 TEST_GROUPS := $(shell echo "$(TEST_PROGS)" | tr ' ' '\n' | \

tools/testing/selftests/ublk/test_common.sh

@@ -15,6 +15,16 @@ _have_program() {
 	return 1
 }
 
+# Sleep with awareness of parallel execution.
+# Usage: _ublk_sleep <normal_secs> <parallel_secs>
+_ublk_sleep() {
+	if [ "${JOBS:-1}" -gt 1 ]; then
+		sleep "$2"
+	else
+		sleep "$1"
+	fi
+}
+
 _get_disk_dev_t() {
 	local dev_id=$1
 	local dev

tools/testing/selftests/ublk/test_part_02.sh

@@ -33,7 +33,7 @@ _test_partition_scan_no_hang()
 	# The add command should return quickly because partition scan is async.
 	# Now sleep briefly to let the async partition scan work start and hit
 	# the delay in the fault_inject handler.
-	sleep 1
+	_ublk_sleep 1 5
 
 	# Kill the ublk daemon while partition scan is potentially blocked
 	# And check state transitions properly