docs: cgroup-v2: fix misc.events key format descriptiongrafted

In misc cgroup, misc.events does not output a simple "max" key. Instead,
each registered misc resource outputs a separate key suffixed with ".max"
(i.e., "<res>.max").
Update the documentation to clarify that the entry key is "<res>.max".

Suggested-by: Michal Koutný <mkoutny@suse.com>
Signed-off-by: Cheng Lingfei <chenglingfei@foxmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

1 files changed, 43 insertions, 0 deletions

diff --git a/include/asm-generic/error-injection.h b/include/asm-generic/error-injection.h
new file mode 100644
index 000000000..b05253f68
--- /dev/null
+++ b/include/asm-generic/error-injection.h
@@ -0,0 +1,43 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_GENERIC_ERROR_INJECTION_H
+#define _ASM_GENERIC_ERROR_INJECTION_H
+
+#if defined(__KERNEL__) && !defined(__ASSEMBLY__)
+enum {
+	EI_ETYPE_NULL,		/* Return NULL if failure */
+	EI_ETYPE_ERRNO,		/* Return -ERRNO if failure */
+	EI_ETYPE_ERRNO_NULL,	/* Return -ERRNO or NULL if failure */
+	EI_ETYPE_TRUE,		/* Return true if failure */
+};
+
+struct error_injection_entry {
+	unsigned long	addr;
+	int		etype;
+};
+
+struct pt_regs;
+
+#ifdef CONFIG_FUNCTION_ERROR_INJECTION
+/*
+ * Whitelist generating macro. Specify functions which can be error-injectable
+ * using this macro. If you unsure what is required for the error-injectable
+ * functions, please read Documentation/fault-injection/fault-injection.rst
+ * 'Error Injectable Functions' section.
+ */
+#define ALLOW_ERROR_INJECTION(fname, _etype)				\
+static struct error_injection_entry __used				\
+	__section("_error_injection_whitelist")				\
+	_eil_addr_##fname = {						\
+		.addr = (unsigned long)fname,				\
+		.etype = EI_ETYPE_##_etype,				\
+	}
+
+void override_function_with_return(struct pt_regs *regs);
+#else
+#define ALLOW_ERROR_INJECTION(fname, _etype)
+
+static inline void override_function_with_return(struct pt_regs *regs) { }
+#endif
+#endif
+
+#endif /* _ASM_GENERIC_ERROR_INJECTION_H */