selftests: ublk: make sure _add_ublk_dev can return in sub-shell

Detach ublk daemon from the starting process completely by double-fork and
clearing its process group, so that `_add_ublk_dev` can return from sub-shell.

Then it is more friendly for writing shell test script for adding/recovering
ublk device.

Prepare for running ublk test in parallel.

Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20250412023035.2649275-5-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/tools/testing/selftests/ublk/kublk.c b/tools/testing/selftests/ublk/kublk.c
index 74cf70b2f28e516fff0e039ffb0d932271bce6e6..381e31acaad94f852649d3179a263ee03b6908cb 100644 (file)
--- a/tools/testing/selftests/ublk/kublk.c
+++ b/tools/testing/selftests/ublk/kublk.c
@@ -654,6 +654,8 @@ static int ublk_send_dev_event(const struct dev_ctx *ctx, int dev_id)
        if (write(evtfd, &id, sizeof(id)) != sizeof(id))
                return -EINVAL;
 
+       close(evtfd);
+
        return 0;
 }
 
@@ -889,24 +891,40 @@ static int cmd_dev_add(struct dev_ctx *ctx)
                exit(-1);
        }
 
-       setsid();
        res = fork();
        if (res == 0) {
+               int res2;
+
+               setsid();
+               res2 = fork();
+               if (res2 == 0) {
+                       /* prepare for detaching */
+                       close(STDIN_FILENO);
+                       close(STDOUT_FILENO);
+                       close(STDERR_FILENO);
 run:
-               res = __cmd_dev_add(ctx);
-               return res;
+                       res = __cmd_dev_add(ctx);
+                       return res;
+               } else {
+                       /* detached from the foreground task */
+                       exit(EXIT_SUCCESS);
+               }
        } else if (res > 0) {
                uint64_t id;
+               int exit_code = EXIT_FAILURE;
 
                res = read(ctx->_evtfd, &id, sizeof(id));
                close(ctx->_evtfd);
                if (res == sizeof(id) && id != ERROR_EVTFD_DEVID) {
                        ctx->dev_id = id - 1;
-                       return __cmd_dev_list(ctx);
+                       if (__cmd_dev_list(ctx) >= 0)
+                               exit_code = EXIT_SUCCESS;
                }
-               exit(EXIT_FAILURE);
+               /* wait for child and detach from it */
+               wait(NULL);
+               exit(exit_code);
        } else {
-               return res;
+               exit(EXIT_FAILURE);
        }
 }
 

diff --git a/tools/testing/selftests/ublk/test_common.sh b/tools/testing/selftests/ublk/test_common.sh
index c7d04da7235aab8ddae983d93b891ad15116edd2..c43bd1d5c9c085444be215a907228366e16868b0 100755 (executable)
--- a/tools/testing/selftests/ublk/test_common.sh
+++ b/tools/testing/selftests/ublk/test_common.sh
@@ -170,7 +170,6 @@ _have_feature()
 }
 
 _add_ublk_dev() {
-       local kublk_temp;
        local dev_id;
 
        if [ ! -c /dev/ublk-control ]; then
@@ -182,17 +181,17 @@ _add_ublk_dev() {
                fi
        fi
 
-       kublk_temp=$(mktemp /tmp/kublk-XXXXXX)
-       if ! "${UBLK_PROG}" add "$@" > "${kublk_temp}" 2>&1; then
+       if ! dev_id=$("${UBLK_PROG}" add "$@" | grep "dev id" | awk -F '[ :]' '{print $3}'); then
                echo "fail to add ublk dev $*"
-               rm -f "${kublk_temp}"
                return 255
        fi
-
-       dev_id=$(grep "dev id" "${kublk_temp}" | awk -F '[ :]' '{print $3}')
        udevadm settle
-       rm -f "${kublk_temp}"
-       echo "${dev_id}"
+
+       if [[ "$dev_id" =~ ^[0-9]+$ ]]; then
+               echo "${dev_id}"
+       else
+               return 255
+       fi
 }
 
 # kill the ublk daemon and return ublk device state

diff --git a/tools/testing/selftests/ublk/test_stress_01.sh b/tools/testing/selftests/ublk/test_stress_01.sh
index 4c37a2cf13a377e36b4168f598e60174e6538694..61fdbdfe70bc47f7442dd72e284b1ba0b66b5930 100755 (executable)
--- a/tools/testing/selftests/ublk/test_stress_01.sh
+++ b/tools/testing/selftests/ublk/test_stress_01.sh
@@ -4,19 +4,19 @@
 . "$(cd "$(dirname "$0")" && pwd)"/test_common.sh
 TID="stress_01"
 ERR_CODE=0
-DEV_ID=-1
 
 ublk_io_and_remove()
 {
        local size=$1
+       local dev_id
        shift 1
 
-       DEV_ID=$(_add_ublk_dev "$@")
+       dev_id=$(_add_ublk_dev "$@")
        _check_add_dev $TID $?
 
        [ "$UBLK_TEST_QUIET" -eq 0 ] && echo "run ublk IO vs. remove device(ublk add $*)"
-       if ! __run_io_and_remove "${DEV_ID}" "${size}" "no"; then
-               echo "/dev/ublkc${DEV_ID} isn't removed"
+       if ! __run_io_and_remove "$dev_id" "${size}" "no"; then
+               echo "/dev/ublkc$dev_id isn't removed"
                exit 255
        fi
 }

diff --git a/tools/testing/selftests/ublk/test_stress_02.sh b/tools/testing/selftests/ublk/test_stress_02.sh
index 4b6ad441d5000cc0b253bf85e79caff93e711c01..7643e58637c8b85fcc7c826d019c7ba345da2688 100755 (executable)
--- a/tools/testing/selftests/ublk/test_stress_02.sh
+++ b/tools/testing/selftests/ublk/test_stress_02.sh
@@ -4,19 +4,19 @@
 . "$(cd "$(dirname "$0")" && pwd)"/test_common.sh
 TID="stress_02"
 ERR_CODE=0
-DEV_ID=-1
 
 ublk_io_and_kill_daemon()
 {
        local size=$1
+       local dev_id
        shift 1
 
-       DEV_ID=$(_add_ublk_dev "$@")
+       dev_id=$(_add_ublk_dev "$@")
        _check_add_dev $TID $?
 
        [ "$UBLK_TEST_QUIET" -eq 0 ] && echo "run ublk IO vs kill ublk server(ublk add $*)"
-       if ! __run_io_and_remove "${DEV_ID}" "${size}" "yes"; then
-               echo "/dev/ublkc${DEV_ID} isn't removed res ${res}"
+       if ! __run_io_and_remove "$dev_id" "${size}" "yes"; then
+               echo "/dev/ublkc$dev_id isn't removed res ${res}"
                exit 255
        fi
 }