v4.19.13 snapshot.
diff --git a/include/linux/string_helpers.h b/include/linux/string_helpers.h
new file mode 100644
index 0000000..d23c503
--- /dev/null
+++ b/include/linux/string_helpers.h
@@ -0,0 +1,79 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_STRING_HELPERS_H_
+#define _LINUX_STRING_HELPERS_H_
+
+#include <linux/types.h>
+
+struct file;
+struct task_struct;
+
+/* Descriptions of the types of units to
+ * print in */
+enum string_size_units {
+ STRING_UNITS_10, /* use powers of 10^3 (standard SI) */
+ STRING_UNITS_2, /* use binary powers of 2^10 */
+};
+
+void string_get_size(u64 size, u64 blk_size, enum string_size_units units,
+ char *buf, int len);
+
+#define UNESCAPE_SPACE 0x01
+#define UNESCAPE_OCTAL 0x02
+#define UNESCAPE_HEX 0x04
+#define UNESCAPE_SPECIAL 0x08
+#define UNESCAPE_ANY \
+ (UNESCAPE_SPACE | UNESCAPE_OCTAL | UNESCAPE_HEX | UNESCAPE_SPECIAL)
+
+int string_unescape(char *src, char *dst, size_t size, unsigned int flags);
+
+static inline int string_unescape_inplace(char *buf, unsigned int flags)
+{
+ return string_unescape(buf, buf, 0, flags);
+}
+
+static inline int string_unescape_any(char *src, char *dst, size_t size)
+{
+ return string_unescape(src, dst, size, UNESCAPE_ANY);
+}
+
+static inline int string_unescape_any_inplace(char *buf)
+{
+ return string_unescape_any(buf, buf, 0);
+}
+
+#define ESCAPE_SPACE 0x01
+#define ESCAPE_SPECIAL 0x02
+#define ESCAPE_NULL 0x04
+#define ESCAPE_OCTAL 0x08
+#define ESCAPE_ANY \
+ (ESCAPE_SPACE | ESCAPE_OCTAL | ESCAPE_SPECIAL | ESCAPE_NULL)
+#define ESCAPE_NP 0x10
+#define ESCAPE_ANY_NP (ESCAPE_ANY | ESCAPE_NP)
+#define ESCAPE_HEX 0x20
+
+int string_escape_mem(const char *src, size_t isz, char *dst, size_t osz,
+ unsigned int flags, const char *only);
+
+static inline int string_escape_mem_any_np(const char *src, size_t isz,
+ char *dst, size_t osz, const char *only)
+{
+ return string_escape_mem(src, isz, dst, osz, ESCAPE_ANY_NP, only);
+}
+
+static inline int string_escape_str(const char *src, char *dst, size_t sz,
+ unsigned int flags, const char *only)
+{
+ return string_escape_mem(src, strlen(src), dst, sz, flags, only);
+}
+
+static inline int string_escape_str_any_np(const char *src, char *dst,
+ size_t sz, const char *only)
+{
+ return string_escape_str(src, dst, sz, ESCAPE_ANY_NP, only);
+}
+
+char *kstrdup_quotable(const char *src, gfp_t gfp);
+char *kstrdup_quotable_cmdline(struct task_struct *task, gfp_t gfp);
+char *kstrdup_quotable_file(struct file *file, gfp_t gfp);
+
+#endif