[PATCH v2 3/3] common/rc: notrun if io_uring is disabled by sysctl

Zorro Lang
2024-03-11T16:20:39Z

If kernel supports io_uring, userspace still can/might disable that
supporting by set /proc/sys/kernel/io_uring_disabled=2. Let's notrun
if io_uring is disabled by that way.

Signed-off-by: Zorro Lang <zlang@kernel.org>
---
README | 6 ++++++
common/rc | 10 ++++++++++
src/feature.c | 19 ++++++++++++-------
3 files changed, 28 insertions(+), 7 deletions(-)

diff --git a/README b/README
index c46690c4..477136de 100644
--- a/README
+++ b/README
@@ -142,6 +142,12 @@ Setup Environment
https://www.lscdweb.com/registered/udf_verifier.html, then copy the udf_test
binary to xfstests/src/.

+8. (optional) To do io_uring related testing, please make sure below 3 things:
+ 1) kernel is built with CONFIG_IO_URING=y
+ 2) sysctl -w kernel.io_uring_disabled=0 (or set it to 2 to disable io_uring
+ testing dynamically if kernel supports)
+ 3) install liburing development package contains liburing.h before building
+ fstests

For example, to run the tests with loopback partitions:

diff --git a/common/rc b/common/rc
index 50dde313..1406d8d9 100644
--- a/common/rc
+++ b/common/rc
@@ -2317,6 +2317,8 @@ _require_aiodio()
# this test requires that the kernel supports IO_URING
_require_io_uring()
{
+ local n
+
$here/src/feature -R
case $? in
0)
@@ -2324,6 +2326,14 @@ _require_io_uring()
1)
_notrun "kernel does not support IO_URING"
;;
+ 2)
+ n=$(sysctl -n kernel.io_uring_disabled 2>/dev/null)
+ if [ "$n" != "0" ];then
+ _notrun "io_uring isn't enabled totally by admin"
+ else
+ _fail "unexpected EPERM error, please check selinux or something else"
+ fi
+ ;;
*)
_fail "unexpected error testing for IO_URING support"
;;
diff --git a/src/feature.c b/src/feature.c
index 941f96fb..7e474ce5 100644
--- a/src/feature.c
+++ b/src/feature.c
@@ -232,15 +232,20 @@ check_uring_support(void)
int err;

err = io_uring_queue_init(1, &ring, 0);
- if (err == 0)
+ switch (err) {
+ case 0:
return 0;
-
- if (err == -ENOSYS) /* CONFIG_IO_URING=n */
+ case -ENOSYS:
+ /* CONFIG_IO_URING=n */
return 1;
-
- fprintf(stderr, "unexpected error from io_uring_queue_init(): %s\n",
- strerror(-err));
- return 2;
+ case -EPERM:
+ /* Might be due to sysctl io_uring_disabled isn't 0 */
+ return 2;
+ default:
+ fprintf(stderr, "unexpected error from io_uring_queue_init(): %s\n",
+ strerror(-err));
+ return 100;
+ }
#else
/* liburing is unavailable, assume IO_URING is unsupported */
return 1;
--
2.43.0