lib: hex2bin converts ascii hexadecimal string to binary

Similar to the kgdb_hex2mem() code, hex2bin converts a string
to binary using the hex_to_bin() library call.

Changelog:
- Replace parameter names with src/dst (based on David Howell's comment)
- Add 'const' where needed (based on David Howell's comment)
- Replace int with size_t (based on David Howell's comment)

Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
Acked-by: Serge E. Hallyn <serge@hallyn.com>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>

2 files changed, 17 insertions, 0 deletions

diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index a35b4f7332f0..d0fbc043de60 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -265,6 +265,7 @@ static inline char *pack_hex_byte(char *buf, u8 byte)
 }
 
 extern int hex_to_bin(char ch);
+extern void hex2bin(u8 *dst, const char *src, size_t count);
 
 /*
  * General tracing related utility functions - trace_printk(),
diff --git a/lib/hexdump.c b/lib/hexdump.c
index 5d7a4802c562..b66b2bd67952 100644
--- a/lib/hexdump.c
+++ b/lib/hexdump.c
@@ -34,6 +34,22 @@ int hex_to_bin(char ch)
 EXPORT_SYMBOL(hex_to_bin);
 
 /**
+ * hex2bin - convert an ascii hexadecimal string to its binary representation
+ * @dst: binary result
+ * @src: ascii hexadecimal string
+ * @count: result length
+ */
+void hex2bin(u8 *dst, const char *src, size_t count)
+{
+        while (count--) {
+                *dst = hex_to_bin(*src++) << 4;
+                *dst += hex_to_bin(*src++);
+                dst++;
+        }
+}
+EXPORT_SYMBOL(hex2bin);
+
+/**
  * hex_dump_to_buffer - convert a blob of data to "hex ASCII" in memory
  * @buf: data blob to dump
  * @len: number of bytes in the @buf