[PATCH 6/8] selftests: ublk: forbid multiple data copy modes

Caleb Sander Mateos
2025-12-11T05:16:34Z

The kublk mock ublk server allows multiple data copy mode arguments to
be passed on the command line (--zero_copy, --get_data, and --auto_zc).
The ublk device will be created with all the requested feature flags,
however kublk will only use one of the modes to interact with request
data (arbitrarily preferring auto_zc over zero_copy over get_data). To
clarify the intent of the test, don't allow multiple data copy modes to
be specified. Don't set UBLK_F_USER_COPY for zero_copy, as it's an
independent feature. Don't require zero_copy for auto_zc_fallback, as
only auto_zc is needed. Fix the test cases passing multiple data copy
mode arguments.

Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
---
tools/testing/selftests/ublk/kublk.c | 21 ++++++++++++-------
.../testing/selftests/ublk/test_generic_09.sh | 2 +-
.../testing/selftests/ublk/test_stress_03.sh | 4 ++--
.../testing/selftests/ublk/test_stress_04.sh | 2 +-
.../testing/selftests/ublk/test_stress_05.sh | 10 ++++-----
5 files changed, 22 insertions(+), 17 deletions(-)

diff --git a/tools/testing/selftests/ublk/kublk.c b/tools/testing/selftests/ublk/kublk.c
index f8fa102a627f..1765c4806523 100644
--- a/tools/testing/selftests/ublk/kublk.c
+++ b/tools/testing/selftests/ublk/kublk.c
@@ -1611,11 +1611,11 @@ int main(int argc, char *argv[])
break;
case 'd':
ctx.queue_depth = strtol(optarg, NULL, 10);
break;
case 'z':
- ctx.flags |= UBLK_F_SUPPORT_ZERO_COPY | UBLK_F_USER_COPY;
+ ctx.flags |= UBLK_F_SUPPORT_ZERO_COPY;
break;
case 'r':
value = strtol(optarg, NULL, 10);
if (value)
ctx.flags |= UBLK_F_USER_RECOVERY;
@@ -1674,17 +1674,22 @@ int main(int argc, char *argv[])
optind += 1;
break;
}
}

- /* auto_zc_fallback depends on F_AUTO_BUF_REG & F_SUPPORT_ZERO_COPY */
- if (ctx.auto_zc_fallback &&
- !((ctx.flags & UBLK_F_AUTO_BUF_REG) &&
- (ctx.flags & UBLK_F_SUPPORT_ZERO_COPY))) {
- ublk_err("%s: auto_zc_fallback is set but neither "
- "F_AUTO_BUF_REG nor F_SUPPORT_ZERO_COPY is enabled\n",
- __func__);
+ /* auto_zc_fallback depends on F_AUTO_BUF_REG */
+ if (ctx.auto_zc_fallback && !(ctx.flags & UBLK_F_AUTO_BUF_REG)) {
+ ublk_err("%s: auto_zc_fallback is set but F_AUTO_BUF_REG is disabled\n",
+ __func__);
+ return -EINVAL;
+ }
+
+ if (!!(ctx.flags & UBLK_F_SUPPORT_ZERO_COPY) +
+ !!(ctx.flags & UBLK_F_NEED_GET_DATA) +
+ !!(ctx.flags & UBLK_F_USER_COPY) +
+ !!(ctx.flags & UBLK_F_AUTO_BUF_REG) > 1) {
+ fprintf(stderr, "too many data copy modes specified\n");
return -EINVAL;
}

i = optind;
while (i < argc && ctx.nr_files < MAX_BACK_FILES) {
diff --git a/tools/testing/selftests/ublk/test_generic_09.sh b/tools/testing/selftests/ublk/test_generic_09.sh
index bb6f77ca5522..145e17b3d2b0 100755
--- a/tools/testing/selftests/ublk/test_generic_09.sh
+++ b/tools/testing/selftests/ublk/test_generic_09.sh
@@ -14,11 +14,11 @@ if ! _have_program fio; then
exit "$UBLK_SKIP_CODE"
fi

_prep_test "null" "basic IO test"

-dev_id=$(_add_ublk_dev -t null -z --auto_zc --auto_zc_fallback)
+dev_id=$(_add_ublk_dev -t null --auto_zc --auto_zc_fallback)
_check_add_dev $TID $?

# run fio over the two disks
fio --name=job1 --filename=/dev/ublkb"${dev_id}" --ioengine=libaio --rw=readwrite --iodepth=32 --size=256M > /dev/null 2>&1
ERR_CODE=$?
diff --git a/tools/testing/selftests/ublk/test_stress_03.sh b/tools/testing/selftests/ublk/test_stress_03.sh
index 3ed4c9b2d8c0..8e9f2786ef9c 100755
--- a/tools/testing/selftests/ublk/test_stress_03.sh
+++ b/tools/testing/selftests/ublk/test_stress_03.sh
@@ -36,19 +36,19 @@ wait

if _have_feature "AUTO_BUF_REG"; then
ublk_io_and_remove 8G -t null -q 4 --auto_zc &
ublk_io_and_remove 256M -t loop -q 4 --auto_zc "${UBLK_BACKFILES[0]}" &
ublk_io_and_remove 256M -t stripe -q 4 --auto_zc "${UBLK_BACKFILES[1]}" "${UBLK_BACKFILES[2]}" &
- ublk_io_and_remove 8G -t null -q 4 -z --auto_zc --auto_zc_fallback &
+ ublk_io_and_remove 8G -t null -q 4 --auto_zc --auto_zc_fallback &
wait
fi

if _have_feature "PER_IO_DAEMON"; then
ublk_io_and_remove 8G -t null -q 4 --auto_zc --nthreads 8 --per_io_tasks &
ublk_io_and_remove 256M -t loop -q 4 --auto_zc --nthreads 8 --per_io_tasks "${UBLK_BACKFILES[0]}" &
ublk_io_and_remove 256M -t stripe -q 4 --auto_zc --nthreads 8 --per_io_tasks "${UBLK_BACKFILES[1]}" "${UBLK_BACKFILES[2]}" &
- ublk_io_and_remove 8G -t null -q 4 -z --auto_zc --auto_zc_fallback --nthreads 8 --per_io_tasks &
+ ublk_io_and_remove 8G -t null -q 4 --auto_zc --auto_zc_fallback --nthreads 8 --per_io_tasks &
wait
fi

_cleanup_test "stress"
_show_result $TID $ERR_CODE
diff --git a/tools/testing/selftests/ublk/test_stress_04.sh b/tools/testing/selftests/ublk/test_stress_04.sh
index c7220723b537..6e165a1f90b4 100755
--- a/tools/testing/selftests/ublk/test_stress_04.sh
+++ b/tools/testing/selftests/ublk/test_stress_04.sh
@@ -35,11 +35,11 @@ wait

if _have_feature "AUTO_BUF_REG"; then
ublk_io_and_kill_daemon 8G -t null -q 4 --auto_zc &
ublk_io_and_kill_daemon 256M -t loop -q 4 --auto_zc "${UBLK_BACKFILES[0]}" &
ublk_io_and_kill_daemon 256M -t stripe -q 4 --auto_zc --no_ublk_fixed_fd "${UBLK_BACKFILES[1]}" "${UBLK_BACKFILES[2]}" &
- ublk_io_and_kill_daemon 8G -t null -q 4 -z --auto_zc --auto_zc_fallback &
+ ublk_io_and_kill_daemon 8G -t null -q 4 --auto_zc --auto_zc_fallback &
wait
fi

if _have_feature "PER_IO_DAEMON"; then
ublk_io_and_kill_daemon 8G -t null -q 4 --auto_zc --nthreads 8 --per_io_tasks &
diff --git a/tools/testing/selftests/ublk/test_stress_05.sh b/tools/testing/selftests/ublk/test_stress_05.sh
index 274295061042..09b94c36f2ba 100755
--- a/tools/testing/selftests/ublk/test_stress_05.sh
+++ b/tools/testing/selftests/ublk/test_stress_05.sh
@@ -56,21 +56,21 @@ for reissue in $(seq 0 1); do
wait
done

if _have_feature "ZERO_COPY"; then
for reissue in $(seq 0 1); do
- ublk_io_and_remove 8G -t null -q 4 -g -z -r 1 -i "$reissue" &
- ublk_io_and_remove 256M -t loop -q 4 -g -z -r 1 -i "$reissue" "${UBLK_BACKFILES[1]}" &
+ ublk_io_and_remove 8G -t null -q 4 -z -r 1 -i "$reissue" &
+ ublk_io_and_remove 256M -t loop -q 4 -z -r 1 -i "$reissue" "${UBLK_BACKFILES[1]}" &
wait
done
fi

if _have_feature "AUTO_BUF_REG"; then
for reissue in $(seq 0 1); do
- ublk_io_and_remove 8G -t null -q 4 -g --auto_zc -r 1 -i "$reissue" &
- ublk_io_and_remove 256M -t loop -q 4 -g --auto_zc -r 1 -i "$reissue" "${UBLK_BACKFILES[1]}" &
- ublk_io_and_remove 8G -t null -q 4 -g -z --auto_zc --auto_zc_fallback -r 1 -i "$reissue" &
+ ublk_io_and_remove 8G -t null -q 4 --auto_zc -r 1 -i "$reissue" &
+ ublk_io_and_remove 256M -t loop -q 4 --auto_zc -r 1 -i "$reissue" "${UBLK_BACKFILES[1]}" &
+ ublk_io_and_remove 8G -t null -q 4 --auto_zc --auto_zc_fallback -r 1 -i "$reissue" &
wait
done
fi

if _have_feature "PER_IO_DAEMON"; then
--
2.45.2