bpf: Add bpf_cpumask_first_and() kfunc

We currently provide bpf_cpumask_first(), bpf_cpumask_any(), and
bpf_cpumask_any_and() kfuncs. bpf_cpumask_any() and
bpf_cpumask_any_and() are confusing misnomers in that they actually just
call cpumask_first() and cpumask_first_and() respectively.

We'll replace them with bpf_cpumask_any_distribute() and
bpf_cpumask_any_distribute_and() kfuncs in a subsequent patch, so let's
ensure feature parity by adding a bpf_cpumask_first_and() kfunc to
account for bpf_cpumask_any_and() being removed.

Signed-off-by: David Vernet <void@manifault.com>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/r/20230610035053.117605-1-void@manifault.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

diff --git a/kernel/bpf/cpumask.c b/kernel/bpf/cpumask.c
index 7efdf5d..9416c8a 100644 (file)
--- a/kernel/bpf/cpumask.c
+++ b/kernel/bpf/cpumask.c
@@ -132,6 +132,21 @@ __bpf_kfunc u32 bpf_cpumask_first_zero(const struct cpumask *cpumask)
 }
 
 /**
+ * bpf_cpumask_first_and() - Return the index of the first nonzero bit from the
+ *                          AND of two cpumasks.
+ * @src1: The first cpumask.
+ * @src2: The second cpumask.
+ *
+ * Find the index of the first nonzero bit of the AND of two cpumasks.
+ * struct bpf_cpumask pointers may be safely passed to @src1 and @src2.
+ */
+__bpf_kfunc u32 bpf_cpumask_first_and(const struct cpumask *src1,
+                                     const struct cpumask *src2)
+{
+       return cpumask_first_and(src1, src2);
+}
+
+/**
  * bpf_cpumask_set_cpu() - Set a bit for a CPU in a BPF cpumask.
  * @cpu: The CPU to be set in the cpumask.
  * @cpumask: The BPF cpumask in which a bit is being set.
@@ -406,6 +421,7 @@ BTF_ID_FLAGS(func, bpf_cpumask_release, KF_RELEASE)
 BTF_ID_FLAGS(func, bpf_cpumask_acquire, KF_ACQUIRE | KF_TRUSTED_ARGS)
 BTF_ID_FLAGS(func, bpf_cpumask_first, KF_RCU)
 BTF_ID_FLAGS(func, bpf_cpumask_first_zero, KF_RCU)
+BTF_ID_FLAGS(func, bpf_cpumask_first_and, KF_RCU)
 BTF_ID_FLAGS(func, bpf_cpumask_set_cpu, KF_RCU)
 BTF_ID_FLAGS(func, bpf_cpumask_clear_cpu, KF_RCU)
 BTF_ID_FLAGS(func, bpf_cpumask_test_cpu, KF_RCU)