[PATCH 01/24] selftests/resctrl: Split fill_buf to allow tests finer-grained control

[Ilpo Järvinen]

MBM, MBA and CMT test cases use run_fill_buf() to loop indefinitely
around the buffer. CAT test case is different and doesn't want to loop
around the buffer continuously.

Split fill_cache() so that both the use cases are easier to control by
creating separate functions for buffer allocation and looping around
the buffer. Make those functions available for tests. The new interface
is based on returning/passing pointers instead of the startptr global
pointer variable that can now be removed. The deallocation can use
free() directly.

This change is part of preparation for new CAT test which allocates a
buffer and does multiple passes over the same buffer (but not in an
infinite loop).

Co-developed-by: Fenghua Yu <fenghua.yu@xxxxxxxxx>
Signed-off-by: Fenghua Yu <fenghua.yu@xxxxxxxxx>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@xxxxxxxxxxxxxxx>
---
 tools/testing/selftests/resctrl/fill_buf.c | 26 +++++++++++++---------
 1 file changed, 15 insertions(+), 11 deletions(-)

diff --git a/tools/testing/selftests/resctrl/fill_buf.c b/tools/testing/selftests/resctrl/fill_buf.c
index 0d425f26583a..f9893edda869 100644
--- a/tools/testing/selftests/resctrl/fill_buf.c
+++ b/tools/testing/selftests/resctrl/fill_buf.c
@@ -135,33 +135,37 @@ static int fill_cache_write(unsigned char *buf, size_t buf_size, bool once)
 	return 0;
 }
 
-static int fill_cache(size_t buf_size, int memflush, int op, bool once)
+static unsigned char *alloc_buffer(size_t buf_size, int memflush)
 {
 	unsigned char *buf;
-	int ret;
 
 	buf = malloc_and_init_memory(buf_size);
 	if (!buf)
-		return -1;
+		return NULL;
 
 	/* Flush the memory before using to avoid "cache hot pages" effect */
 	if (memflush)
 		mem_flush(buf, buf_size);
 
+	return buf;
+}
+
+static int fill_cache(size_t buf_size, int memflush, int op, bool once)
+{
+	unsigned char *buf;
+	int ret;
+
+	buf = alloc_buffer(buf_size, memflush);
+	if (buf == NULL)
+		return -1;
+
 	if (op == 0)
 		ret = fill_cache_read(buf, buf_size, once);
 	else
 		ret = fill_cache_write(buf, buf_size, once);
-
 	free(buf);
 
-	if (ret) {
-		printf("\n Error in fill cache read/write...\n");
-		return -1;
-	}
-
-
-	return 0;
+	return ret;
 }
 
 int run_fill_buf(size_t span, int memflush, int op, bool once)
-- 
2.30.2