linux_compat: move kmemdup() from ubifs.c to linux_compat.c

linux_compat.c is the best place for kmemdup(), which is currenly used
only in ubifs.c, but will also be used when other kernel files
(in my case, lib/crypto/x509_cert_parser.c and pkcs7_parser.c) will be
imported. So just move it.
Signed-off-by: NAKASHI Takahiro <takahiro.akashi@linaro.org>
Reviewed-by: NHeinrich Schuchardt <xypron.glpk@gmx.de>

fs/ubifs/ubifs.c

@@ -18,6 +18,7 @@
 #include "ubifs.h"
 #include <u-boot/zlib.h>
 
+#include <linux/compat.h>
 #include <linux/err.h>
 #include <linux/lzo.h>
 
@@ -70,24 +71,6 @@ struct ubifs_compressor *ubifs_compressors[UBIFS_COMPR_TYPES_CNT];
 
 
 #ifdef __UBOOT__
-/* from mm/util.c */
-
-/**
- * kmemdup - duplicate region of memory
- *
- * @src: memory region to duplicate
- * @len: memory region length
- * @gfp: GFP mask to use
- */
-void *kmemdup(const void *src, size_t len, gfp_t gfp)
-{
-	void *p;
-
-	p = kmalloc(len, gfp);
-	if (p)
-		memcpy(p, src, len);
-	return p;
-}
 
 struct crypto_comp {
 	int compressor;

lib/linux_compat.c

@@ -40,3 +40,22 @@ void *kmem_cache_alloc(struct kmem_cache *obj, int flag)
 {
 	return malloc_cache_aligned(obj->sz);
 }
+
+/**
+ * kmemdup - duplicate region of memory
+ *
+ * @src: memory region to duplicate
+ * @len: memory region length
+ * @gfp: GFP mask to use
+ *
+ * Return: newly allocated copy of @src or %NULL in case of error
+ */
+void *kmemdup(const void *src, size_t len, gfp_t gfp)
+{
+	void *p;
+
+	p = kmalloc(len, gfp);
+	if (p)
+		memcpy(p, src, len);
+	return p;
+}