[PATCH V1 09/13] selftests/resctrl: Modularize fill_buf for new CAT test case

[Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com>]

Currently fill_buf (in-built benchmark) runs as a separate process and it
runs indefinitely looping around given buffer either reading it or writing
to it. But, some future test cases might want to start and stop looping
around the buffer as they see fit. So, modularize fill_buf to support this
use case.

Signed-off-by: Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com>
---
 tools/testing/selftests/resctrl/fill_buf.c | 66 ++++++++++++++++++++----------
 1 file changed, 44 insertions(+), 22 deletions(-)

diff --git a/tools/testing/selftests/resctrl/fill_buf.c b/tools/testing/selftests/resctrl/fill_buf.c
index 9ede7b63f059..204ae8870a32 100644
--- a/tools/testing/selftests/resctrl/fill_buf.c
+++ b/tools/testing/selftests/resctrl/fill_buf.c
@@ -23,7 +23,7 @@
 #define PAGE_SIZE		(4 * 1024)
 #define MB			(1024 * 1024)
 
-static unsigned char *startptr;
+static unsigned char *startptr, *endptr;
 
 static void sb(void)
 {
@@ -82,13 +82,13 @@ static void *malloc_and_init_memory(size_t s)
 	return p;
 }
 
-static int fill_one_span_read(unsigned char *start_ptr, unsigned char *end_ptr)
+static int fill_one_span_read(void)
 {
 	unsigned char sum, *p;
 
 	sum = 0;
-	p = start_ptr;
-	while (p < end_ptr) {
+	p = startptr;
+	while (p < endptr) {
 		sum += *p;
 		p += (CL_SIZE / 2);
 	}
@@ -96,26 +96,24 @@ static int fill_one_span_read(unsigned char *start_ptr, unsigned char *end_ptr)
 	return sum;
 }
 
-static
-void fill_one_span_write(unsigned char *start_ptr, unsigned char *end_ptr)
+static void fill_one_span_write(void)
 {
 	unsigned char *p;
 
-	p = start_ptr;
-	while (p < end_ptr) {
+	p = startptr;
+	while (p < endptr) {
 		*p = '1';
 		p += (CL_SIZE / 2);
 	}
 }
 
-static int fill_cache_read(unsigned char *start_ptr, unsigned char *end_ptr,
-			   char *resctrl_val)
+static int fill_cache_read(char *resctrl_val)
 {
 	int ret = 0;
 	FILE *fp;
 
 	while (1) {
-		ret = fill_one_span_read(start_ptr, end_ptr);
+		ret = fill_one_span_read();
 		if (!strcmp(resctrl_val, "cat"))
 			break;
 	}
@@ -130,11 +128,10 @@ static int fill_cache_read(unsigned char *start_ptr, unsigned char *end_ptr,
 	return 0;
 }
 
-static int fill_cache_write(unsigned char *start_ptr, unsigned char *end_ptr,
-			    char *resctrl_val)
+static int fill_cache_write(char *resctrl_val)
 {
 	while (1) {
-		fill_one_span_write(start_ptr, end_ptr);
+		fill_one_span_write();
 		if (!strcmp(resctrl_val, "cat"))
 			break;
 	}
@@ -142,24 +139,25 @@ static int fill_cache_write(unsigned char *start_ptr, unsigned char *end_ptr,
 	return 0;
 }
 
-static int
-fill_cache(unsigned long long buf_size, int malloc_and_init, int memflush,
-	   int op, char *resctrl_val)
+static
+int init_buffer(unsigned long long buf_size, int malloc_and_init, int memflush)
 {
 	unsigned char *start_ptr, *end_ptr;
 	unsigned long long i;
-	int ret;
 
 	if (malloc_and_init)
 		start_ptr = malloc_and_init_memory(buf_size);
 	else
 		start_ptr = malloc(buf_size);
 
-	if (!start_ptr)
+	if (!start_ptr) {
+		printf("Failed to allocate memory to buffer\n");
 		return -1;
+	}
 
-	startptr = start_ptr;
 	end_ptr = start_ptr + buf_size;
+	endptr = end_ptr;
+	startptr = start_ptr;
 
 	/*
 	 * It's better to touch the memory once to avoid any compiler
@@ -176,16 +174,40 @@ fill_cache(unsigned long long buf_size, int malloc_and_init, int memflush,
 	if (memflush)
 		mem_flush(start_ptr, buf_size);
 
+	return 0;
+}
+
+static int use_buffer_forever(int op, char *resctrl_val)
+{
+	int ret;
+
 	if (op == 0)
-		ret = fill_cache_read(start_ptr, end_ptr, resctrl_val);
+		ret = fill_cache_read(resctrl_val);
 	else
-		ret = fill_cache_write(start_ptr, end_ptr, resctrl_val);
+		ret = fill_cache_write(resctrl_val);
 
 	if (ret) {
 		printf("\n Errror in fill cache read/write...\n");
 		return -1;
 	}
 
+	return 0;
+}
+
+static int
+fill_cache(unsigned long long buf_size, int malloc_and_init, int memflush,
+	   int op, char *resctrl_val)
+{
+	int ret;
+
+	ret = init_buffer(buf_size, malloc_and_init, memflush);
+	if (ret)
+		return ret;
+
+	ret = use_buffer_forever(op, resctrl_val);
+	if (ret)
+		return ret;
+
 	free(startptr);
 
 	return 0;
-- 
2.7.4