[PATCH 4/7] perf diff: Introduce fmt_to_data_file() helper

[Namhyung Kim <namhyung@kernel.org>]

The fmt_to_data_file() is to retrieve struct data__file from
perf_hpp_fmt which is embedded in diff_hpp_fmt.  It'll be used by sort
callback functions later.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
---
 tools/perf/builtin-diff.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/tools/perf/builtin-diff.c b/tools/perf/builtin-diff.c
index 3f86737da2c4..ae8f62151b34 100644
--- a/tools/perf/builtin-diff.c
+++ b/tools/perf/builtin-diff.c
@@ -390,6 +390,15 @@ static void perf_evlist__collapse_resort(struct perf_evlist *evlist)
 	}
 }
 
+static struct data__file *fmt_to_data_file(struct perf_hpp_fmt *fmt)
+{
+	struct diff_hpp_fmt *dfmt = container_of(fmt, struct diff_hpp_fmt, fmt);
+	void *ptr = dfmt - dfmt->idx;
+	struct data__file *d = container_of(ptr, struct data__file, fmt);
+
+	return d;
+}
+
 static struct hist_entry*
 get_pair_data(struct hist_entry *he, struct data__file *d)
 {
@@ -407,8 +416,7 @@ get_pair_data(struct hist_entry *he, struct data__file *d)
 static struct hist_entry*
 get_pair_fmt(struct hist_entry *he, struct diff_hpp_fmt *dfmt)
 {
-	void *ptr = dfmt - dfmt->idx;
-	struct data__file *d = container_of(ptr, struct data__file, fmt);
+	struct data__file *d = fmt_to_data_file(&dfmt->fmt);
 
 	return get_pair_data(he, d);
 }
-- 
2.1.3