1 files changed, 112 insertions, 2 deletions

diff --git a/kernel/gcov/fs.c b/kernel/gcov/fs.c
index e5eb5ea7ea59..5c3086cad8f9 100644
--- a/kernel/gcov/fs.c
+++ b/kernel/gcov/fs.c
@@ -26,6 +26,7 @@
 #include <linux/slab.h>
 #include <linux/mutex.h>
 #include <linux/seq_file.h>
+#include <linux/mm.h>
 #include "gcov.h"
 
 /**
@@ -58,7 +59,7 @@ struct gcov_node {
 	struct dentry *dentry;
 	struct dentry **links;
 	int num_loaded;
-	char name[0];
+	char name[];
 };
 
 static const char objtree[] = OBJTREE;
@@ -85,6 +86,115 @@ static int __init gcov_persist_setup(char *str)
 }
 __setup("gcov_persist=", gcov_persist_setup);
 
+#define ITER_STRIDE	PAGE_SIZE
+
+/**
+ * struct gcov_iterator - specifies current file position in logical records
+ * @info: associated profiling data
+ * @buffer: buffer containing file data
+ * @size: size of buffer
+ * @pos: current position in file
+ */
+struct gcov_iterator {
+	struct gcov_info *info;
+	size_t size;
+	loff_t pos;
+	char buffer[];
+};
+
+/**
+ * gcov_iter_new - allocate and initialize profiling data iterator
+ * @info: profiling data set to be iterated
+ *
+ * Return file iterator on success, %NULL otherwise.
+ */
+static struct gcov_iterator *gcov_iter_new(struct gcov_info *info)
+{
+	struct gcov_iterator *iter;
+	size_t size;
+
+	/* Dry-run to get the actual buffer size. */
+	size = convert_to_gcda(NULL, info);
+
+	iter = kvmalloc(struct_size(iter, buffer, size), GFP_KERNEL);
+	if (!iter)
+		return NULL;
+
+	iter->info = info;
+	iter->size = size;
+	convert_to_gcda(iter->buffer, info);
+
+	return iter;
+}
+
+
+/**
+ * gcov_iter_free - free iterator data
+ * @iter: file iterator
+ */
+static void gcov_iter_free(struct gcov_iterator *iter)
+{
+	kvfree(iter);
+}
+
+/**
+ * gcov_iter_get_info - return profiling data set for given file iterator
+ * @iter: file iterator
+ */
+static struct gcov_info *gcov_iter_get_info(struct gcov_iterator *iter)
+{
+	return iter->info;
+}
+
+/**
+ * gcov_iter_start - reset file iterator to starting position
+ * @iter: file iterator
+ */
+static void gcov_iter_start(struct gcov_iterator *iter)
+{
+	iter->pos = 0;
+}
+
+/**
+ * gcov_iter_next - advance file iterator to next logical record
+ * @iter: file iterator
+ *
+ * Return zero if new position is valid, non-zero if iterator has reached end.
+ */
+static int gcov_iter_next(struct gcov_iterator *iter)
+{
+	if (iter->pos < iter->size)
+		iter->pos += ITER_STRIDE;
+
+	if (iter->pos >= iter->size)
+		return -EINVAL;
+
+	return 0;
+}
+
+/**
+ * gcov_iter_write - write data for current pos to seq_file
+ * @iter: file iterator
+ * @seq: seq_file handle
+ *
+ * Return zero on success, non-zero otherwise.
+ */
+static int gcov_iter_write(struct gcov_iterator *iter, struct seq_file *seq)
+{
+	size_t len;
+
+	if (iter->pos >= iter->size)
+		return -EINVAL;
+
+	len = ITER_STRIDE;
+	if (iter->pos + len > iter->size)
+		len = iter->size - iter->pos;
+
+	seq_write(seq, iter->buffer + iter->pos, len);
+
+	return 0;
+}
+
 /*
  * seq_file.start() implementation for gcov data files. Note that the
  * gcov_iterator interface is designed to be more restrictive than seq_file
@@ -108,9 +218,9 @@ static void *gcov_seq_next(struct seq_file *seq, void *data, loff_t *pos)
 {
 	struct gcov_iterator *iter = data;
 
+	(*pos)++;
 	if (gcov_iter_next(iter))
 		return NULL;
-	(*pos)++;
 
 	return iter;
 }