[v3] syscalls/ioprio: Add test cases for I/O priority

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 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     | 91 +++++++++++++++++++
 .../kernel/syscalls/ioprio/ioprio_get01.c     | 47 ++++++++++
 .../kernel/syscalls/ioprio/ioprio_set01.c     | 67 ++++++++++++++
 .../kernel/syscalls/ioprio/ioprio_set02.c     | 67 ++++++++++++++
 .../kernel/syscalls/ioprio/ioprio_set03.c     | 59 ++++++++++++
 8 files changed, 346 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

Hi,

Thanks for your contribution!
This looks good to me, just some improvements down below:

On 2019-08-04 02:25, Linus Walleij wrote:
> 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 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     | 91 +++++++++++++++++++
>  .../kernel/syscalls/ioprio/ioprio_get01.c     | 47 ++++++++++
>  .../kernel/syscalls/ioprio/ioprio_set01.c     | 67 ++++++++++++++
>  .../kernel/syscalls/ioprio/ioprio_set02.c     | 67 ++++++++++++++
>  .../kernel/syscalls/ioprio/ioprio_set03.c     | 59 ++++++++++++
>  8 files changed, 346 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..be7fc5fbcf10
> --- /dev/null
> +++ b/testcases/kernel/syscalls/ioprio/ioprio.h
> @@ -0,0 +1,91 @@
> +/* 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,
> +};
> +
> +#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 ioprio_get(int which, int who)

These function names should probably be changed to something like 
"sys_ioprio_{get,set}" in order to avoid using the same names as glibc 
(if these calls ever get added).

> +{
> +	return tst_syscall(__NR_ioprio_get, which, who);
> +}
> +
> +static inline int 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 = 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);

Maybe you could return 1/0 depending on success and than handle the 
output in the corresponding test case
(maybe not, let's see what others think)

> +}
> +
> +#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..e0acf1670fc9
> --- /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(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..07fe53caa3d6
> --- /dev/null
> +++ b/testcases/kernel/syscalls/ioprio/ioprio_set01.c
> @@ -0,0 +1,67 @@
> +// 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(ioprio_get(IOPRIO_WHO_PROCESS, 0));
> +
> +	if (TST_RET == -1) {
> +		tst_res(TFAIL | TTERRNO, "ioprio_get failed");
> +		/* Try to continue anyway */

Maybe this should end here with tst_brk(TBROK), because if this fails it 
would probably be better to abort.

> +		class = IOPRIO_CLASS_NONE;
> +		prio = 4;
> +	} else {
> +		class = IOPRIO_PRIO_CLASS(TST_RET);
> +		prio = IOPRIO_PRIO_LEVEL(TST_RET);
> +		tst_res(TPASS, "ioprio_get returned class %s prio %d",
> +			 to_class_str[class], prio);

'TINFO' is a better choice here, nothing test-worthy was accomplished, 
so far.

> +	}
> +
> +	/* 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++;

The actual priority does not matter here, so it would be a good idea to 
so something like this:

- "#define NUM_PROIOS (8)" in the header file
- set the priority to (prio + 1) % NUM_PRIOS

That way it is guaranteed to be a valid number and no more checks are 
needed.


> +
> +	TEST(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 -= 2;

same here^

> +	TEST(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..5cdc6f0dbb1b
> --- /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 < 8; prio++) {

again, using a defined number for number-of-priorities could help to 
remove the magic number 8.

> +		TEST(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 8 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 < 8; prio++) {
> +		TEST(ioprio_set(IOPRIO_WHO_PROCESS, 0,
> +				IOPRIO_PRIO_VALUE(class, prio)));
> +		if (TST_RET == -1) {
> +			tst_res(TFAIL | TTERRNO, "ioprio_set IOPRIO_CLASS_IDLE failed");

Is there a reason why the priority is not printed here? If not, please 
add this.

> +			fail_in_loop = 1;
> +		}
> +	}
> +	if (!fail_in_loop)
> +		tst_res(TPASS, "tested all 8 prios in class %s",
> +			 to_class_str[class]);
> +
> +	/* Test NONE scheduling */
> +	class = IOPRIO_CLASS_NONE;
> +	TEST(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..1e3ac291c004
> --- /dev/null
> +++ b/testcases/kernel/syscalls/ioprio/ioprio_set03.c
> @@ -0,0 +1,59 @@
> +// 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;

adding a variable "prio" would increase readability further down.

> +
> +	class = IOPRIO_CLASS_BE;
> +
> +	/* Test to fail with prio 8, first set prio 4 */
> +	ioprio_set(IOPRIO_WHO_PROCESS, 0,
> +		   IOPRIO_PRIO_VALUE(class, 4));
> +	TEST(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, "return EINVAL %d",

I would replace this line with something like "tst_res(TPASS | TTERRNO, 
"Returned correct error for wrong prio");"

> +				errno);

In ltp you would usually use "TST_ERR" instead of "errno"

> +		else
> +			tst_res(TFAIL, "ioprio_set returns wrong errno %d",
> +				errno);
> +	} 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(ioprio_set(IOPRIO_WHO_PROCESS, 0,
> +			IOPRIO_PRIO_VALUE(class, 4)));
> +	if (TST_RET == -1) {
> +		tst_res(TPASS, "tested illegal priority with class %s",
> +			 to_class_str[class]);

Using TINFO instead of TPASS makes more sense because you give a 
PASS/FAIL message a few lines further down

> +		if (errno == EINVAL)
> +			tst_res(TPASS, "return EINVAL %d",
> +				errno);

Same as above^

> +		else
> +			tst_res(TFAIL, "ioprio_set returns wrong errno %d",
> +				errno);
> +	} else {
> +		tst_res(TFAIL, "ioprio_set IOPRIO_CLASS_NONE should fail");
> +	}
> +}
> +
> +static struct tst_test test = {
> +	.test_all = run,
> +};