[LTP] [PATCH v4] syscalls/ioprio: Add test cases for I/O priority

[LTP] [PATCH v4] syscalls/ioprio: Add test cases for I/O priority

[Linus Walleij]

The ioprio_get/ioprio_set syscalls are used primarily by the
userspace tool "ionice" to set priority of a process, user or
process group toward the I/O (block layer) scheduler.

This adds a simple iprio_get test and two more verbose tests
for ioprio_set.

Cc: Anders Roxell <anders.roxell@linaro.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Cyril Hrubis <chrubis@suse.cz>
Cc: Christian Amann <camann@suse.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
---
ChangeLog v3->v4:
- Rename syscall wrappers ioprio_get() and ioprio_set() to
  sys_ioprio_get() and sys_ioprio_set() to match the glibc
  convention.
- Issue tst_brk(TBROK ... if we can't even get the inital
  priority in the first prio set test.
- Add a define for the number of priorities and use arithmetic
  MOD to wrap priorities around from what they are at
  test start. Also use this define in prio test loops.
- Also report failed priority level in IDLE scheduling class
  priority test.
- Use TPASS|TTERRNO to print successful failure with the right
  error numbers on negative tests.
- Use TINFO on prints that more serve as information than as
  result of any test.
ChangeLog v2->v3:
- Add testcases to runtest/syscalls
- Add an info blurb to each test file
- Move syscall wrappers into ioprio.h
- Add helper to check that class is in range and use that
  consistently in the test cases
- Check the new priorities for validity when we bump the prio
  +1 and -2.
- Factor prio/class check function into the header as well
  and use the same in both setting tests
- Don't get the current prio before looping over all 8
  prios in ioprio_set02
- Break out the negative tests from ioprio_set02 to ioprio_set03
- Also check that the negative tests return EINVAL
- Diet down includes
- Use tst_syscall()
- Drop .min_kver since we use tst_syscall() to determine if
  the syscall is there
- Fixed relevant checkpatch warnings, left 80 col warnings
  as these are non-compulsory
ChangeLog v1->v2:
- Use the new test fixture "tst_test.h"
- Fix up legalese in the Makefile to a simple SPDX tag.
- Test from v2.6.13 when the syscall was introduced
---
 runtest/syscalls                              |  5 +
 testcases/kernel/syscalls/ioprio/.gitignore   |  4 +
 testcases/kernel/syscalls/ioprio/Makefile     |  6 ++
 testcases/kernel/syscalls/ioprio/ioprio.h     | 94 +++++++++++++++++++
 .../kernel/syscalls/ioprio/ioprio_get01.c     | 47 ++++++++++
 .../kernel/syscalls/ioprio/ioprio_set01.c     | 63 +++++++++++++
 .../kernel/syscalls/ioprio/ioprio_set02.c     | 67 +++++++++++++
 .../kernel/syscalls/ioprio/ioprio_set03.c     | 57 +++++++++++
 8 files changed, 343 insertions(+)
 create mode 100644 testcases/kernel/syscalls/ioprio/.gitignore
 create mode 100644 testcases/kernel/syscalls/ioprio/Makefile
 create mode 100644 testcases/kernel/syscalls/ioprio/ioprio.h
 create mode 100644 testcases/kernel/syscalls/ioprio/ioprio_get01.c
 create mode 100644 testcases/kernel/syscalls/ioprio/ioprio_set01.c
 create mode 100644 testcases/kernel/syscalls/ioprio/ioprio_set02.c
 create mode 100644 testcases/kernel/syscalls/ioprio/ioprio_set03.c

diff --git a/runtest/syscalls b/runtest/syscalls
index 42c20042376a..700471a2cf07 100644
--- a/runtest/syscalls
+++ b/runtest/syscalls
@@ -542,6 +542,11 @@ ioperm02 ioperm02
 iopl01 iopl01
 iopl02 iopl02
 
+ioprio_get01 ioprio_get01
+ioprio_set01 ioprio_set01
+ioprio_set02 ioprio_set02
+ioprio_set03 ioprio_set03
+
 io_cancel01 io_cancel01
 io_destroy01 io_destroy01
 io_getevents01 io_getevents01
diff --git a/testcases/kernel/syscalls/ioprio/.gitignore b/testcases/kernel/syscalls/ioprio/.gitignore
new file mode 100644
index 000000000000..373079bf2219
--- /dev/null
+++ b/testcases/kernel/syscalls/ioprio/.gitignore
@@ -0,0 +1,4 @@
+ioprio_get01
+ioprio_set01
+ioprio_set02
+ioprio_set03
diff --git a/testcases/kernel/syscalls/ioprio/Makefile b/testcases/kernel/syscalls/ioprio/Makefile
new file mode 100644
index 000000000000..5ea7d67db123
--- /dev/null
+++ b/testcases/kernel/syscalls/ioprio/Makefile
@@ -0,0 +1,6 @@
+# SPDX-License-Identifier: GPL-2.0-or-later
+
+top_srcdir		?= ../../../..
+
+include $(top_srcdir)/include/mk/testcases.mk
+include $(top_srcdir)/include/mk/generic_leaf_target.mk
diff --git a/testcases/kernel/syscalls/ioprio/ioprio.h b/testcases/kernel/syscalls/ioprio/ioprio.h
new file mode 100644
index 000000000000..c74380475740
--- /dev/null
+++ b/testcases/kernel/syscalls/ioprio/ioprio.h
@@ -0,0 +1,94 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (c) 2019 Linus Walleij <linus.walleij@linaro.org>
+ */
+
+#ifndef LTP_IOPRIO_H
+#define LTP_IOPRIO_H
+
+enum {
+	IOPRIO_CLASS_NONE = 0,
+	IOPRIO_CLASS_RT,
+	IOPRIO_CLASS_BE,
+	IOPRIO_CLASS_IDLE,
+};
+
+enum {
+	IOPRIO_WHO_PROCESS = 1,
+	IOPRIO_WHO_PGRP,
+	IOPRIO_WHO_USER,
+};
+
+/* The I/O scheduler classes have 8 priorities 0..7 except for the IDLE class */
+#define IOPRIO_PRIO_NUM		8
+
+#define IOPRIO_CLASS_SHIFT	(13)
+#define IOPRIO_PRIO_MASK	((1UL << IOPRIO_CLASS_SHIFT) - 1)
+
+#define IOPRIO_PRIO_CLASS(data)	((data) >> IOPRIO_CLASS_SHIFT)
+#define IOPRIO_PRIO_LEVEL(data)	((data) & IOPRIO_PRIO_MASK)
+#define IOPRIO_PRIO_VALUE(class, data)	(((class) << IOPRIO_CLASS_SHIFT) | data)
+
+static const char * const to_class_str[] = {
+	[IOPRIO_CLASS_NONE] = "NONE",
+	[IOPRIO_CLASS_RT]   = "REALTIME",
+	[IOPRIO_CLASS_BE]   = "BEST-EFFORT",
+	[IOPRIO_CLASS_IDLE] = "IDLE"
+};
+
+static inline int sys_ioprio_get(int which, int who)
+{
+	return tst_syscall(__NR_ioprio_get, which, who);
+}
+
+static inline int sys_ioprio_set(int which, int who, int ioprio)
+{
+	return tst_syscall(__NR_ioprio_set, which, who, ioprio);
+}
+
+/* Priority range from 0 (highest) to 7 (lowest) */
+static inline int prio_in_range(int prio)
+{
+	if ((prio < 0) || (prio > 7))
+		return 0;
+	return 1;
+}
+
+/* Priority range from 0 to 3 using the enum */
+static inline int class_in_range(int class)
+{
+	if ((class < IOPRIO_CLASS_NONE) || (class > IOPRIO_CLASS_IDLE))
+		return 0;
+	return 1;
+}
+
+static inline void ioprio_check_setting(int class, int prio, int report)
+{
+	int res;
+	int newclass, newprio;
+
+	res = sys_ioprio_get(IOPRIO_WHO_PROCESS, 0);
+	if (res == -1) {
+		tst_res(TFAIL | TTERRNO,
+			 "reading back prio failed");
+		return;
+	}
+
+	newclass = IOPRIO_PRIO_CLASS(res);
+	newprio = IOPRIO_PRIO_LEVEL(res);
+	if (newclass != class)
+		tst_res(TFAIL,
+			"wrong class after setting, expected %s got %s",
+			to_class_str[class],
+			to_class_str[newclass]);
+	else if (newprio != prio)
+		tst_res(TFAIL,
+			"wrong prio after setting, expected %d got %d",
+			prio, newprio);
+	else if (report)
+		tst_res(TPASS, "ioprio_set new class %s, new prio %d",
+			to_class_str[newclass],
+			newprio);
+}
+
+#endif
diff --git a/testcases/kernel/syscalls/ioprio/ioprio_get01.c b/testcases/kernel/syscalls/ioprio/ioprio_get01.c
new file mode 100644
index 000000000000..6e822434ee7f
--- /dev/null
+++ b/testcases/kernel/syscalls/ioprio/ioprio_get01.c
@@ -0,0 +1,47 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2019 Linus Walleij <linus.walleij@linaro.org>
+ *
+ * Description:
+ * Basic ioprio_get() test. Gets the current process I/O priority and
+ * checks that the values are sane.
+ */
+#include <sys/types.h>
+#include <sys/syscall.h>
+
+#include "tst_test.h"
+#include "lapi/syscalls.h"
+#include "ioprio.h"
+
+static void run(void)
+{
+	int prio, class;
+
+	/* Get the I/O priority for the current process */
+	TEST(sys_ioprio_get(IOPRIO_WHO_PROCESS, 0));
+
+	if (TST_RET == -1) {
+		tst_res(TFAIL | TTERRNO, "ioprio_get failed");
+		return;
+	}
+
+	class = IOPRIO_PRIO_CLASS(TST_RET);
+	prio = IOPRIO_PRIO_LEVEL(TST_RET);
+
+	if (!prio_in_range(prio)) {
+		tst_res(TFAIL, "ioprio out of range (%d)", prio);
+		return;
+	}
+
+	if (!class_in_range(class)) {
+		tst_res(TFAIL, "ioprio class of range (%d)", class);
+		return;
+	}
+
+	tst_res(TPASS, "ioprio_get returned class %s prio %d",
+		to_class_str[class], prio);
+}
+
+static struct tst_test test = {
+	.test_all = run,
+};
diff --git a/testcases/kernel/syscalls/ioprio/ioprio_set01.c b/testcases/kernel/syscalls/ioprio/ioprio_set01.c
new file mode 100644
index 000000000000..3cc1e51fc5c0
--- /dev/null
+++ b/testcases/kernel/syscalls/ioprio/ioprio_set01.c
@@ -0,0 +1,63 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2019 Linus Walleij <linus.walleij@linaro.org>
+ *
+ * Description:
+ * Basic ioprio_set() test. Gets the current process I/O priority and
+ * bumps it up one notch, then down two notches and checks that the
+ * new priority is reported back correctly.
+ */
+#include <sys/types.h>
+#include <sys/syscall.h>
+
+#include "tst_test.h"
+#include "lapi/syscalls.h"
+#include "ioprio.h"
+
+static void run(void)
+{
+	int class, prio;
+
+	/* Get the I/O priority for the current process */
+	TEST(sys_ioprio_get(IOPRIO_WHO_PROCESS, 0));
+
+	if (TST_RET == -1)
+		tst_brk(TBROK | TTERRNO, "ioprio_get failed");
+
+	class = IOPRIO_PRIO_CLASS(TST_RET);
+	prio = IOPRIO_PRIO_LEVEL(TST_RET);
+	tst_res(TINFO, "ioprio_get returned class %s prio %d",
+		to_class_str[class], prio);
+
+	/* Bump prio to what it was + 1 */
+	class = IOPRIO_CLASS_BE;
+	if (!prio_in_range(prio + 1)) {
+		tst_res(TFAIL, "ioprio increase out of range (%d)", prio + 1);
+		return;
+	}
+	prio = (prio + 1) % IOPRIO_PRIO_NUM;
+
+	TEST(sys_ioprio_set(IOPRIO_WHO_PROCESS, 0,
+			    IOPRIO_PRIO_VALUE(class, prio)));
+	if (TST_RET == -1)
+		tst_res(TFAIL | TTERRNO, "ioprio_set failed");
+	else
+		ioprio_check_setting(class, prio, 1);
+
+	/* Bump prio down two notches */
+	if (!prio_in_range(prio - 2)) {
+		tst_res(TFAIL, "ioprio increase out of range (%d)", prio - 2);
+		return;
+	}
+	prio = (prio - 2) % IOPRIO_PRIO_NUM;
+	TEST(sys_ioprio_set(IOPRIO_WHO_PROCESS, 0,
+			    IOPRIO_PRIO_VALUE(class, prio)));
+	if (TST_RET == -1)
+		tst_res(TFAIL | TTERRNO, "ioprio_set failed");
+	else
+		ioprio_check_setting(class, prio, 1);
+}
+
+static struct tst_test test = {
+	.test_all = run,
+};
diff --git a/testcases/kernel/syscalls/ioprio/ioprio_set02.c b/testcases/kernel/syscalls/ioprio/ioprio_set02.c
new file mode 100644
index 000000000000..5472b549a268
--- /dev/null
+++ b/testcases/kernel/syscalls/ioprio/ioprio_set02.c
@@ -0,0 +1,67 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2019 Linus Walleij <linus.walleij@linaro.org>
+ *
+ * Description:
+ * Extended ioprio_set() test. Gets the current process I/O priority and
+ * tests to set all 8 priority levels for best effort prioritym then
+ * switches to test all 8 priority levels for idle priority. Also test
+ * some non-working priorities to make sure they don't work.
+ */
+#include <sys/types.h>
+#include <sys/syscall.h>
+
+#include "tst_test.h"
+#include "lapi/syscalls.h"
+#include "ioprio.h"
+
+static void run(void)
+{
+	int class, prio;
+	int fail_in_loop;
+
+	/* Bump to best effort scheduling, all 8 priorities */
+	class = IOPRIO_CLASS_BE;
+
+	fail_in_loop = 0;
+	for (prio = 0; prio < IOPRIO_PRIO_NUM; prio++) {
+		TEST(sys_ioprio_set(IOPRIO_WHO_PROCESS, 0,
+				    IOPRIO_PRIO_VALUE(class, prio)));
+		if (TST_RET == -1) {
+			tst_res(TFAIL | TTERRNO, "ioprio_set IOPRIO_CLASS_BE prio %d failed", prio);
+			fail_in_loop = 1;
+		}
+	}
+	if (!fail_in_loop)
+		tst_res(TPASS, "tested all prios in class %s",
+			 to_class_str[class]);
+
+	/* Bump down to idle scheduling */
+	class = IOPRIO_CLASS_IDLE;
+
+	fail_in_loop = 0;
+	for (prio = 0; prio < IOPRIO_PRIO_NUM; prio++) {
+		TEST(sys_ioprio_set(IOPRIO_WHO_PROCESS, 0,
+				    IOPRIO_PRIO_VALUE(class, prio)));
+		if (TST_RET == -1) {
+			tst_res(TFAIL | TTERRNO, "ioprio_set IOPRIO_CLASS_IDLE prio %d failed", prio);
+			fail_in_loop = 1;
+		}
+	}
+	if (!fail_in_loop)
+		tst_res(TPASS, "tested all prios in class %s",
+			 to_class_str[class]);
+
+	/* Test NONE scheduling */
+	class = IOPRIO_CLASS_NONE;
+	TEST(sys_ioprio_set(IOPRIO_WHO_PROCESS, 0,
+			    IOPRIO_PRIO_VALUE(class, 0)));
+	if (TST_RET == -1)
+		tst_res(TFAIL | TTERRNO, "ioprio_set IOPRIO_CLASS_NONE failed");
+	else
+		ioprio_check_setting(class, 0, 1);
+}
+
+static struct tst_test test = {
+	.test_all = run,
+};
diff --git a/testcases/kernel/syscalls/ioprio/ioprio_set03.c b/testcases/kernel/syscalls/ioprio/ioprio_set03.c
new file mode 100644
index 000000000000..66d61b67e8c1
--- /dev/null
+++ b/testcases/kernel/syscalls/ioprio/ioprio_set03.c
@@ -0,0 +1,57 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2019 Linus Walleij <linus.walleij@linaro.org>
+ *
+ * Description:
+ * Negative ioprio_set() test. Test some non-working priorities to make
+ * sure they don't work.
+ */
+#include <sys/types.h>
+#include <sys/syscall.h>
+
+#include "tst_test.h"
+#include "lapi/syscalls.h"
+#include "ioprio.h"
+
+static void run(void)
+{
+	int class;
+
+	class = IOPRIO_CLASS_BE;
+
+	/* Test to fail with prio 8, first set prio 4 */
+	sys_ioprio_set(IOPRIO_WHO_PROCESS, 0,
+		       IOPRIO_PRIO_VALUE(class, 4));
+	TEST(sys_ioprio_set(IOPRIO_WHO_PROCESS, 0,
+			    IOPRIO_PRIO_VALUE(class, 8)));
+	if (TST_RET == -1) {
+		ioprio_check_setting(class, 4, 1);
+		if (errno == EINVAL)
+			tst_res(TPASS | TTERRNO, "returned correct error for wrong prio");
+		else
+			tst_res(TFAIL, "ioprio_set returns wrong errno %d",
+				TST_ERR);
+	} else {
+		tst_res(TFAIL, "ioprio_set IOPRIO_CLASS_BE prio 8 should not work");
+	}
+
+	/* Any other prio than 0 should not work with NONE */
+	class = IOPRIO_CLASS_NONE;
+	TEST(sys_ioprio_set(IOPRIO_WHO_PROCESS, 0,
+			    IOPRIO_PRIO_VALUE(class, 4)));
+	if (TST_RET == -1) {
+		tst_res(TINFO, "tested illegal priority with class %s",
+			to_class_str[class]);
+		if (errno == EINVAL)
+			tst_res(TPASS | TTERRNO, "returned correct error for wrong prio");
+		else
+			tst_res(TFAIL, "ioprio_set returns wrong errno %d",
+				TST_ERR);
+	} else {
+		tst_res(TFAIL, "ioprio_set IOPRIO_CLASS_NONE should fail");
+	}
+}
+
+static struct tst_test test = {
+	.test_all = run,
+};
-- 
2.21.0

[LTP] [PATCH v4] syscalls/ioprio: Add test cases for I/O priority

[Cyril Hrubis]

Hi!
> diff --git a/testcases/kernel/syscalls/ioprio/ioprio_set01.c b/testcases/kernel/syscalls/ioprio/ioprio_set01.c
> new file mode 100644
> index 000000000000..3cc1e51fc5c0
> --- /dev/null
> +++ b/testcases/kernel/syscalls/ioprio/ioprio_set01.c
> @@ -0,0 +1,63 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * Copyright (c) 2019 Linus Walleij <linus.walleij@linaro.org>
> + *
> + * Description:
> + * Basic ioprio_set() test. Gets the current process I/O priority and
> + * bumps it up one notch, then down two notches and checks that the
> + * new priority is reported back correctly.
> + */
> +#include <sys/types.h>
> +#include <sys/syscall.h>
> +
> +#include "tst_test.h"
> +#include "lapi/syscalls.h"
> +#include "ioprio.h"
> +
> +static void run(void)
> +{
> +	int class, prio;
> +
> +	/* Get the I/O priority for the current process */
> +	TEST(sys_ioprio_get(IOPRIO_WHO_PROCESS, 0));
> +
> +	if (TST_RET == -1)
> +		tst_brk(TBROK | TTERRNO, "ioprio_get failed");
> +
> +	class = IOPRIO_PRIO_CLASS(TST_RET);
> +	prio = IOPRIO_PRIO_LEVEL(TST_RET);
> +	tst_res(TINFO, "ioprio_get returned class %s prio %d",
> +		to_class_str[class], prio);
> +
> +	/* Bump prio to what it was + 1 */
> +	class = IOPRIO_CLASS_BE;
> +	if (!prio_in_range(prio + 1)) {
> +		tst_res(TFAIL, "ioprio increase out of range (%d)", prio + 1);
> +		return;
> +	}
> +	prio = (prio + 1) % IOPRIO_PRIO_NUM;

I guess that the % IOPRION_PRIO_NUM is not needed here since we already
checked that the prio+1 is in range, or do I miss something?

> +	TEST(sys_ioprio_set(IOPRIO_WHO_PROCESS, 0,
> +			    IOPRIO_PRIO_VALUE(class, prio)));
> +	if (TST_RET == -1)
> +		tst_res(TFAIL | TTERRNO, "ioprio_set failed");
> +	else
> +		ioprio_check_setting(class, prio, 1);
> +
> +	/* Bump prio down two notches */
> +	if (!prio_in_range(prio - 2)) {
> +		tst_res(TFAIL, "ioprio increase out of range (%d)", prio - 2);
> +		return;
> +	}
> +	prio = (prio - 2) % IOPRIO_PRIO_NUM;

Here as well.

> +	TEST(sys_ioprio_set(IOPRIO_WHO_PROCESS, 0,
> +			    IOPRIO_PRIO_VALUE(class, prio)));
> +	if (TST_RET == -1)
> +		tst_res(TFAIL | TTERRNO, "ioprio_set failed");
> +	else
> +		ioprio_check_setting(class, prio, 1);
> +}
> +
> +static struct tst_test test = {
> +	.test_all = run,
> +};
> diff --git a/testcases/kernel/syscalls/ioprio/ioprio_set02.c b/testcases/kernel/syscalls/ioprio/ioprio_set02.c
> new file mode 100644
> index 000000000000..5472b549a268
> --- /dev/null
> +++ b/testcases/kernel/syscalls/ioprio/ioprio_set02.c
> @@ -0,0 +1,67 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * Copyright (c) 2019 Linus Walleij <linus.walleij@linaro.org>
> + *
> + * Description:
> + * Extended ioprio_set() test. Gets the current process I/O priority and
                                   ^
				   We are not getting anything here.
> + * tests to set all 8 priority levels for best effort prioritym then
> + * switches to test all 8 priority levels for idle priority. Also test
> + * some non-working priorities to make sure they don't work.
> + */
> +#include <sys/types.h>
> +#include <sys/syscall.h>
> +
> +#include "tst_test.h"
> +#include "lapi/syscalls.h"
> +#include "ioprio.h"
> +
> +static void run(void)
> +{
> +	int class, prio;
> +	int fail_in_loop;
> +
> +	/* Bump to best effort scheduling, all 8 priorities */
> +	class = IOPRIO_CLASS_BE;
> +
> +	fail_in_loop = 0;
> +	for (prio = 0; prio < IOPRIO_PRIO_NUM; prio++) {
> +		TEST(sys_ioprio_set(IOPRIO_WHO_PROCESS, 0,
> +				    IOPRIO_PRIO_VALUE(class, prio)));
> +		if (TST_RET == -1) {
> +			tst_res(TFAIL | TTERRNO, "ioprio_set IOPRIO_CLASS_BE prio %d failed", prio);
> +			fail_in_loop = 1;
> +		}
> +	}
> +	if (!fail_in_loop)
> +		tst_res(TPASS, "tested all prios in class %s",
> +			 to_class_str[class]);
> +
> +	/* Bump down to idle scheduling */
> +	class = IOPRIO_CLASS_IDLE;
> +
> +	fail_in_loop = 0;
> +	for (prio = 0; prio < IOPRIO_PRIO_NUM; prio++) {
> +		TEST(sys_ioprio_set(IOPRIO_WHO_PROCESS, 0,
> +				    IOPRIO_PRIO_VALUE(class, prio)));
> +		if (TST_RET == -1) {
> +			tst_res(TFAIL | TTERRNO, "ioprio_set IOPRIO_CLASS_IDLE prio %d failed", prio);
> +			fail_in_loop = 1;
> +		}
> +	}
> +	if (!fail_in_loop)
> +		tst_res(TPASS, "tested all prios in class %s",
> +			 to_class_str[class]);
> +
> +	/* Test NONE scheduling */
> +	class = IOPRIO_CLASS_NONE;
> +	TEST(sys_ioprio_set(IOPRIO_WHO_PROCESS, 0,
> +			    IOPRIO_PRIO_VALUE(class, 0)));
> +	if (TST_RET == -1)
> +		tst_res(TFAIL | TTERRNO, "ioprio_set IOPRIO_CLASS_NONE failed");
> +	else
> +		ioprio_check_setting(class, 0, 1);
> +}
> +
> +static struct tst_test test = {
> +	.test_all = run,
> +};
> diff --git a/testcases/kernel/syscalls/ioprio/ioprio_set03.c b/testcases/kernel/syscalls/ioprio/ioprio_set03.c
> new file mode 100644
> index 000000000000..66d61b67e8c1
> --- /dev/null
> +++ b/testcases/kernel/syscalls/ioprio/ioprio_set03.c
> @@ -0,0 +1,57 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * Copyright (c) 2019 Linus Walleij <linus.walleij@linaro.org>
> + *
> + * Description:
> + * Negative ioprio_set() test. Test some non-working priorities to make
> + * sure they don't work.
> + */
> +#include <sys/types.h>
> +#include <sys/syscall.h>
> +
> +#include "tst_test.h"
> +#include "lapi/syscalls.h"
> +#include "ioprio.h"
> +
> +static void run(void)
> +{
> +	int class;
> +
> +	class = IOPRIO_CLASS_BE;
> +
> +	/* Test to fail with prio 8, first set prio 4 */
> +	sys_ioprio_set(IOPRIO_WHO_PROCESS, 0,
> +		       IOPRIO_PRIO_VALUE(class, 4));

What do we need this for?

> +	TEST(sys_ioprio_set(IOPRIO_WHO_PROCESS, 0,
> +			    IOPRIO_PRIO_VALUE(class, 8)));
> +	if (TST_RET == -1) {
> +		ioprio_check_setting(class, 4, 1);
> +		if (errno == EINVAL)
> +			tst_res(TPASS | TTERRNO, "returned correct error for wrong prio");
> +		else
> +			tst_res(TFAIL, "ioprio_set returns wrong errno %d",
> +				TST_ERR);
> +	} else {
> +		tst_res(TFAIL, "ioprio_set IOPRIO_CLASS_BE prio 8 should not work");
> +	}
> +
> +	/* Any other prio than 0 should not work with NONE */
> +	class = IOPRIO_CLASS_NONE;
> +	TEST(sys_ioprio_set(IOPRIO_WHO_PROCESS, 0,
> +			    IOPRIO_PRIO_VALUE(class, 4)));
> +	if (TST_RET == -1) {
> +		tst_res(TINFO, "tested illegal priority with class %s",
> +			to_class_str[class]);
> +		if (errno == EINVAL)
> +			tst_res(TPASS | TTERRNO, "returned correct error for wrong prio");
> +		else
> +			tst_res(TFAIL, "ioprio_set returns wrong errno %d",
> +				TST_ERR);
> +	} else {
> +		tst_res(TFAIL, "ioprio_set IOPRIO_CLASS_NONE should fail");
> +	}

This is almost copy&pasted I would consider putting it into a
function...

> +}
> +
> +static struct tst_test test = {
> +	.test_all = run,
> +};

Other than the minor issues this looks good.

Also I can fix these and apply the patch myself, no need to resend v5.

-- 
Cyril Hrubis
chrubis@suse.cz