ioctl: take use of TST_RETRY_FN* macro

To avoid of race with udev, let's use TST_RETRY_FN* macro to loop
access() function for more times.

---Errors---
ioctl_loop01.c:59: PASS: /sys/block/loop0/loop/partscan = 1
ioctl_loop01.c:60: PASS: /sys/block/loop0/loop/autoclear = 0
ioctl_loop01.c:71: FAIL: access /dev/loop0p1 fails
ioctl_loop01.c:77: FAIL: access /sys/block/loop0/loop0p1 fails

ioctl09.c:41: PASS: access /sys/block/loop0/loop0p1 succeeds
ioctl09.c:52: FAIL: access /dev/loop0p1 fails

Fixes: #718
Suggested-by: Cyril Hrubis <chrubis@suse.cz>
Signed-off-by: Li Wang <liwang@redhat.com>
Cc: Yang Xu <xuyang2018.jy@cn.fujitsu.com>
Cc: Jan Stancek <jstancek@redhat.com>
---
 testcases/kernel/syscalls/ioctl/ioctl09.c      | 8 +++++---
 testcases/kernel/syscalls/ioctl/ioctl_loop01.c | 4 ++--
 2 files changed, 7 insertions(+), 5 deletions(-)

----- Original Message -----
>  static void check_partition(int part_num, bool value)
>  {
> -	int ret;
> +	int ret, time_delay;
>  
>  	sprintf(sys_loop_partpath, "/sys/block/loop%d/loop%dp%d",
>  		dev_num, dev_num, part_num);
>  	sprintf(loop_partpath, "%sp%d", dev_path, part_num);
>  
> -	ret = access(sys_loop_partpath, F_OK);
> +	value ? (time_delay = 30) : (time_delay = 1);
> +
> +	ret = TST_RETRY_FN_EXP_BACKOFF(access(sys_loop_partpath, F_OK),
> TST_RETVAL_EQ0, time_delay);

Shouldn't we invert also the check when value == 0? At the moment
there's TST_RETVAL_EQ0 for all cases, but we expect path to exist
only for value == 1, correct?

diff --git a/testcases/kernel/syscalls/ioctl/ioctl09.c b/testcases/kernel/syscalls/ioctl/ioctl09.c
index 151618df41db..dff31d58a054 100644
--- a/testcases/kernel/syscalls/ioctl/ioctl09.c
+++ b/testcases/kernel/syscalls/ioctl/ioctl09.c
@@ -28,6 +28,9 @@ static void change_partition(const char *const cmd[])
                tst_brk(TBROK, "parted return %i", ret);
 }
 
+#define RETVAL_CHECK(x) \
+       ({ value ? TST_RETVAL_EQ0(x) : TST_RETVAL_NOTNULL(x); })
+
 static void check_partition(int part_num, bool value)
 {
        int ret;
@@ -36,7 +39,7 @@ static void check_partition(int part_num, bool value)
                dev_num, dev_num, part_num);
        sprintf(loop_partpath, "%sp%d", dev_path, part_num);
 
-       ret = access(sys_loop_partpath, F_OK);
+       ret = TST_RETRY_FN_EXP_BACKOFF(access(sys_loop_partpath, F_OK), RETVAL_CHECK, 30);
        if (ret == 0)
                tst_res(value ? TPASS : TFAIL, "access %s succeeds",
                        sys_loop_partpath);
@@ -44,7 +47,7 @@ static void check_partition(int part_num, bool value)
                tst_res(value ? TFAIL : TPASS, "access %s fails",
                        sys_loop_partpath);
 
-       ret = access(loop_partpath, F_OK);
+       ret = TST_RETRY_FN_EXP_BACKOFF(access(loop_partpath, F_OK), RETVAL_CHECK, 30);
        if (ret == 0)
                tst_res(value ? TPASS : TFAIL, "access %s succeeds",
                        loop_partpath);

On Wed, Sep 9, 2020 at 4:44 PM Jan Stancek <jstancek@redhat.com> wrote:


> > +     value ? (time_delay = 30) : (time_delay = 1);
> > +
> > +     ret = TST_RETRY_FN_EXP_BACKOFF(access(sys_loop_partpath, F_OK),
> > TST_RETVAL_EQ0, time_delay);
>
> Shouldn't we invert also the check when value == 0? At the moment
> there's TST_RETVAL_EQ0 for all cases, but we expect path to exist
> only for value == 1, correct?
>

Obviously yes, and I have thought a while to decrease the
waiting time for the nonzero return, but didn't realize there is also
a macro named TST_RETVAL_NOTNULL(x) can be used:).

Thanks for the suggestion, I think your method is better.


> diff --git a/testcases/kernel/syscalls/ioctl/ioctl09.c
> b/testcases/kernel/syscalls/ioctl/ioctl09.c
> index 151618df41db..dff31d58a054 100644
> --- a/testcases/kernel/syscalls/ioctl/ioctl09.c
> +++ b/testcases/kernel/syscalls/ioctl/ioctl09.c
> @@ -28,6 +28,9 @@ static void change_partition(const char *const cmd[])
>                 tst_brk(TBROK, "parted return %i", ret);
>  }
>
> +#define RETVAL_CHECK(x) \
> +       ({ value ? TST_RETVAL_EQ0(x) : TST_RETVAL_NOTNULL(x); })
> +
>  static void check_partition(int part_num, bool value)
>  {
>         int ret;
> @@ -36,7 +39,7 @@ static void check_partition(int part_num, bool value)
>                 dev_num, dev_num, part_num);
>         sprintf(loop_partpath, "%sp%d", dev_path, part_num);
>
> -       ret = access(sys_loop_partpath, F_OK);
> +       ret = TST_RETRY_FN_EXP_BACKOFF(access(sys_loop_partpath, F_OK),
> RETVAL_CHECK, 30);
>         if (ret == 0)
>                 tst_res(value ? TPASS : TFAIL, "access %s succeeds",
>                         sys_loop_partpath);
> @@ -44,7 +47,7 @@ static void check_partition(int part_num, bool value)
>                 tst_res(value ? TFAIL : TPASS, "access %s fails",
>                         sys_loop_partpath);
>
> -       ret = access(loop_partpath, F_OK);
> +       ret = TST_RETRY_FN_EXP_BACKOFF(access(loop_partpath, F_OK),
> RETVAL_CHECK, 30);
>         if (ret == 0)
>                 tst_res(value ? TPASS : TFAIL, "access %s succeeds",
>                         loop_partpath);
>
>