selftests/bpf: Update bpf_cpumask_any* tests to use bpf_cpumask_any_distribute*

In a prior patch, we removed the bpf_cpumask_any() and
bpf_cpumask_any_and() kfuncs, and replaced them with
bpf_cpumas

selftests/bpf: Update bpf_cpumask_any* tests to use bpf_cpumask_any_distribute*

In a prior patch, we removed the bpf_cpumask_any() and
bpf_cpumask_any_and() kfuncs, and replaced them with
bpf_cpumask_any_distribute() and bpf_cpumask_any_distribute_and().
The advertised semantics between the two kfuncs were identical, with the
former always returning the first CPU, and the latter actually returning
any CPU.

This patch updates the selftests for these kfuncs to use the new names.

Signed-off-by: David Vernet <void@manifault.com>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/r/20230610035053.117605-4-void@manifault.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

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selftests/bpf: Add test for new bpf_cpumask_first_and() kfunc

A prior patch added a new kfunc called bpf_cpumask_first_and() which
wraps cpumask_first_and(). This patch adds a selftest to validate i

selftests/bpf: Add test for new bpf_cpumask_first_and() kfunc

A prior patch added a new kfunc called bpf_cpumask_first_and() which
wraps cpumask_first_and(). This patch adds a selftest to validate its
behavior.

Signed-off-by: David Vernet <void@manifault.com>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/r/20230610035053.117605-2-void@manifault.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

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bpf: Remove bpf_cpumask_kptr_get() kfunc

Now that struct bpf_cpumask is RCU safe, there's no need for this kfunc.
Rather than doing the following:

private(MASK) static struct bpf_cpumask __kptr *gl

bpf: Remove bpf_cpumask_kptr_get() kfunc

Now that struct bpf_cpumask is RCU safe, there's no need for this kfunc.
Rather than doing the following:

private(MASK) static struct bpf_cpumask __kptr *global;

int BPF_PROG(prog, s32 cpu, ...)
{
struct bpf_cpumask *cpumask;

bpf_rcu_read_lock();
cpumask = bpf_cpumask_kptr_get(&global);
if (!cpumask) {
bpf_rcu_read_unlock();
return -1;
}
bpf_cpumask_setall(cpumask);
...
bpf_cpumask_release(cpumask);
bpf_rcu_read_unlock();
}

Programs can instead simply do (assume same global cpumask):

int BPF_PROG(prog, ...)
{
struct bpf_cpumask *cpumask;

bpf_rcu_read_lock();
cpumask = global;
if (!cpumask) {
bpf_rcu_read_unlock();
return -1;
}
bpf_cpumask_setall(cpumask);
...
bpf_rcu_read_unlock();
}

In other words, no extra atomic acquire / release, and less boilerplate
code.

This patch removes both the kfunc, as well as its selftests and
documentation.

Signed-off-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20230316054028.88924-5-void@manifault.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

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bpf/selftests: Test using global cpumask kptr with RCU

Now that struct bpf_cpumask * is considered an RCU-safe type according
to the verifier, we should add tests that validate its common usages.
Th

bpf/selftests: Test using global cpumask kptr with RCU

Now that struct bpf_cpumask * is considered an RCU-safe type according
to the verifier, we should add tests that validate its common usages.
This patch adds those tests to the cpumask test suite. A subsequent
changes will remove bpf_cpumask_kptr_get(), and will adjust the selftest
and BPF documentation accordingly.

Signed-off-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20230316054028.88924-4-void@manifault.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

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bpf: Rename __kptr_ref -> __kptr and __kptr -> __kptr_untrusted.

__kptr meant to store PTR_UNTRUSTED kernel pointers inside bpf maps.
The concept felt useful, but didn't get much traction,
since bpf

bpf: Rename __kptr_ref -> __kptr and __kptr -> __kptr_untrusted.

__kptr meant to store PTR_UNTRUSTED kernel pointers inside bpf maps.
The concept felt useful, but didn't get much traction,
since bpf_rdonly_cast() was added soon after and bpf programs received
a simpler way to access PTR_UNTRUSTED kernel pointers
without going through restrictive __kptr usage.

Rename __kptr_ref -> __kptr and __kptr -> __kptr_untrusted to indicate
its intended usage.
The main goal of __kptr_untrusted was to read/write such pointers
directly while bpf_kptr_xchg was a mechanism to access refcnted
kernel pointers. The next patch will allow RCU protected __kptr access
with direct read. At that point __kptr_untrusted will be deprecated.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/bpf/20230303041446.3630-2-alexei.starovoitov@gmail.com

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selftests/bpf: Add selftest suite for cpumask kfuncs

A recent patch added a new set of kfuncs for allocating, freeing,
manipulating, and querying cpumasks. This patch adds a new 'cpumask'
selftest s

selftests/bpf: Add selftest suite for cpumask kfuncs

A recent patch added a new set of kfuncs for allocating, freeing,
manipulating, and querying cpumasks. This patch adds a new 'cpumask'
selftest suite which verifies their behavior.

Signed-off-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20230125143816.721952-5-void@manifault.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

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