1 files changed, 58 insertions, 16 deletions

diff --git a/mm/util.c b/mm/util.c
index ace2aea69f1a..bf340d806868 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -5,22 +5,7 @@
 #include <asm/uaccess.h>
 
 /**
- * __kzalloc - allocate memory. The memory is set to zero.
- * @size: how many bytes of memory are required.
- * @flags: the type of memory to allocate.
- */
-void *__kzalloc(size_t size, gfp_t flags)
-{
-	void *ret = kmalloc_track_caller(size, flags);
-	if (ret)
-		memset(ret, 0, size);
-	return ret;
-}
-EXPORT_SYMBOL(__kzalloc);
-
-/*
  * kstrdup - allocate space for and copy an existing string
- *
  * @s: the string to duplicate
  * @gfp: the GFP mask used in the kmalloc() call when allocating memory
  */
@@ -41,6 +26,30 @@ char *kstrdup(const char *s, gfp_t gfp)
 EXPORT_SYMBOL(kstrdup);
 
 /**
+ * kstrndup - allocate space for and copy an existing string
+ * @s: the string to duplicate
+ * @max: read at most @max chars from @s
+ * @gfp: the GFP mask used in the kmalloc() call when allocating memory
+ */
+char *kstrndup(const char *s, size_t max, gfp_t gfp)
+{
+	size_t len;
+	char *buf;
+
+	if (!s)
+		return NULL;
+
+	len = strnlen(s, max);
+	buf = kmalloc_track_caller(len+1, gfp);
+	if (buf) {
+		memcpy(buf, s, len);
+		buf[len] = '\0';
+	}
+	return buf;
+}
+EXPORT_SYMBOL(kstrndup);
+
+/**
  * kmemdup - duplicate region of memory
  *
  * @src: memory region to duplicate
@@ -58,9 +67,42 @@ void *kmemdup(const void *src, size_t len, gfp_t gfp)
 }
 EXPORT_SYMBOL(kmemdup);
 
+/**
+ * krealloc - reallocate memory. The contents will remain unchanged.
+ * @p: object to reallocate memory for.
+ * @new_size: how many bytes of memory are required.
+ * @flags: the type of memory to allocate.
+ *
+ * The contents of the object pointed to are preserved up to the
+ * lesser of the new and old sizes.  If @p is %NULL, krealloc()
+ * behaves exactly like kmalloc().  If @size is 0 and @p is not a
+ * %NULL pointer, the object pointed to is freed.
+ */
+void *krealloc(const void *p, size_t new_size, gfp_t flags)
+{
+	void *ret;
+	size_t ks;
+
+	if (unlikely(!new_size)) {
+		kfree(p);
+		return ZERO_SIZE_PTR;
+	}
+
+	ks = ksize(p);
+	if (ks >= new_size)
+		return (void *)p;
+
+	ret = kmalloc_track_caller(new_size, flags);
+	if (ret) {
+		memcpy(ret, p, min(new_size, ks));
+		kfree(p);
+	}
+	return ret;
+}
+EXPORT_SYMBOL(krealloc);
+
 /*
  * strndup_user - duplicate an existing string from user space
- *
  * @s: The string to duplicate
  * @n: Maximum number of bytes to copy, including the trailing NUL.
  */