selftests: cachestat: Fix build warnings on ppc64

[ Upstream commit bc4d5f5d2debf8bb65fba188313481549ead8576 ]

Fix warnings like:
test_cachestat.c: In function ‘print_cachestat’:
test_cachestat

selftests: cachestat: Fix build warnings on ppc64

[ Upstream commit bc4d5f5d2debf8bb65fba188313481549ead8576 ]

Fix warnings like:
test_cachestat.c: In function ‘print_cachestat’:
test_cachestat.c:30:38: warning: format ‘%llu’ expects argument of
type ‘long long unsigned int’, but argument 2 has type ‘__u64’ {aka
‘long unsigned int’} [-Wformat=]

By switching to unsigned long long for u64 for ppc64 builds.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

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selftests: cachestat: catch failing fsync test on tmpfs

The cachestat kselftest runs a test on a normal file, which is created
temporarily in the current directory. Among the tests it runs there is

selftests: cachestat: catch failing fsync test on tmpfs

The cachestat kselftest runs a test on a normal file, which is created
temporarily in the current directory. Among the tests it runs there is a
call to fsync(), which is expected to clean all dirty pages used by the
file.

However the tmpfs filesystem implements fsync() as noop_fsync(), so the
call will not even attempt to clean anything when this test file happens
to live on a tmpfs instance. This happens in an initramfs, or when the
current directory is in /dev/shm or sometimes /tmp.

To avoid this test failing wrongly, use statfs() to check which filesystem
the test file lives on. If that is "tmpfs", we skip the fsync() test.

Since the fsync test is only one part of the "normal file" test, we now
execute this twice, skipping the fsync part on the first call. This way
only the second test, including the fsync part, would be skipped.

Link: https://lkml.kernel.org/r/20230821160534.3414911-3-andre.przywara@arm.com
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

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selftests: cachestat: test for cachestat availability

Patch series "selftests: cachestat: fix run on older kernels", v2.

I ran all kernel selftests on some test machine, and stumbled upon
cachestat

selftests: cachestat: test for cachestat availability

Patch series "selftests: cachestat: fix run on older kernels", v2.

I ran all kernel selftests on some test machine, and stumbled upon
cachestat failing (among others). These patches fix the run on older
kernels and when the current directory is on a tmpfs instance.


This patch (of 2):

As cachestat is a new syscall, it won't be available on older kernels, for
instance those running on a development machine. At the moment the test
reports all tests as "not ok" in this case.

Test for the cachestat syscall availability first, before doing further
tests, and bail out early with a TAP SKIP comment.

This also uses the opportunity to add the proper TAP headers, and add one
check for proper error handling (illegal file descriptor).

Link: https://lkml.kernel.org/r/20230821160534.3414911-1-andre.przywara@arm.com
Link: https://lkml.kernel.org/r/20230821160534.3414911-2-andre.przywara@arm.com
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Acked-by: Nhat Pham <nphamcs@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

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selftests: cachestat: use proper syscall number macro

At the moment the cachestat syscall number is hard coded into the test
source code.
Remove that and replace it with the proper __NR_cachestat ma

selftests: cachestat: use proper syscall number macro

At the moment the cachestat syscall number is hard coded into the test
source code.
Remove that and replace it with the proper __NR_cachestat macro.
That ensures compatibility should other architectures pick a different
number.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Nhat Pham <nphamcs@gmail.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

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selftests: add selftests for cachestat

Test cachestat on a newly created file, /dev/ files, /proc/ files and a
directory. Also test on a shmem file (which can also be tested with
huge pages since t

selftests: add selftests for cachestat

Test cachestat on a newly created file, /dev/ files, /proc/ files and a
directory. Also test on a shmem file (which can also be tested with
huge pages since tmpfs supports huge pages).

[colin.i.king@gmail.com: fix spelling mistake "trucate" -> "truncate"]
Link: https://lkml.kernel.org/r/20230505110855.2493457-1-colin.i.king@gmail.com
[mpe@ellerman.id.au: avoid excessive stack allocation]
Link: https://lkml.kernel.org/r/877ctfa6yv.fsf@mail.lhotse
Link: https://lkml.kernel.org/r/20230503013608.2431726-4-nphamcs@gmail.com
Signed-off-by: Nhat Pham <nphamcs@gmail.com>
Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Brian Foster <bfoster@redhat.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Colin Ian King <colin.i.king@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

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