diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
index 1cd0357..3e755f2 100644
--- a/tools/perf/util/header.c
+++ b/tools/perf/util/header.c
@@ -1709,7 +1709,7 @@
 			  struct perf_header *ph, int fd,
 			  void *data __maybe_unused)
 {
-	size_t ret;
+	ssize_t ret;
 	u32 nr;
 
 	ret = readn(fd, &nr, sizeof(nr));
@@ -1753,7 +1753,7 @@
 			     void *data __maybe_unused)
 {
 	uint64_t mem;
-	size_t ret;
+	ssize_t ret;
 
 	ret = readn(fd, &mem, sizeof(mem));
 	if (ret != sizeof(mem))
@@ -1822,7 +1822,7 @@
 			   struct perf_header *ph, int fd,
 			   void *data __maybe_unused)
 {
-	size_t ret;
+	ssize_t ret;
 	char *str;
 	u32 nr, i;
 	struct strbuf sb;
@@ -1858,7 +1858,7 @@
 				struct perf_header *ph, int fd,
 				void *data __maybe_unused)
 {
-	size_t ret;
+	ssize_t ret;
 	u32 nr, i;
 	char *str;
 	struct strbuf sb;
@@ -1914,7 +1914,7 @@
 				 struct perf_header *ph, int fd,
 				 void *data __maybe_unused)
 {
-	size_t ret;
+	ssize_t ret;
 	u32 nr, node, i;
 	char *str;
 	uint64_t mem_total, mem_free;
@@ -1974,7 +1974,7 @@
 				struct perf_header *ph, int fd,
 				void *data __maybe_unused)
 {
-	size_t ret;
+	ssize_t ret;
 	char *name;
 	u32 pmu_num;
 	u32 type;
@@ -2534,7 +2534,7 @@
 int perf_file_header__read(struct perf_file_header *header,
 			   struct perf_header *ph, int fd)
 {
-	int ret;
+	ssize_t ret;
 
 	lseek(fd, 0, SEEK_SET);
 
@@ -2628,7 +2628,7 @@
 				       struct perf_header *ph, int fd,
 				       bool repipe)
 {
-	int ret;
+	ssize_t ret;
 
 	ret = readn(fd, header, sizeof(*header));
 	if (ret <= 0)
@@ -2669,7 +2669,7 @@
 	struct perf_event_attr *attr = &f_attr->attr;
 	size_t sz, left;
 	size_t our_sz = sizeof(f_attr->attr);
-	int ret;
+	ssize_t ret;
 
 	memset(f_attr, 0, sizeof(*f_attr));
 
diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
index b0b15e2..4ce146b 100644
--- a/tools/perf/util/session.c
+++ b/tools/perf/util/session.c
@@ -1158,7 +1158,7 @@
 	void *buf = NULL;
 	int skip = 0;
 	u64 head;
-	int err;
+	ssize_t err;
 	void *p;
 
 	perf_tool__fill_defaults(tool);
diff --git a/tools/perf/util/util.c b/tools/perf/util/util.c
index 28a0a89..9440481 100644
--- a/tools/perf/util/util.c
+++ b/tools/perf/util/util.c
@@ -151,12 +151,12 @@
 	return value;
 }
 
-int readn(int fd, void *buf, size_t n)
+ssize_t readn(int fd, void *buf, size_t n)
 {
 	void *buf_start = buf;
 
 	while (n) {
-		int ret = read(fd, buf, n);
+		ssize_t ret = read(fd, buf, n);
 
 		if (ret <= 0)
 			return ret;
diff --git a/tools/perf/util/util.h b/tools/perf/util/util.h
index c8f362d..9f6b928 100644
--- a/tools/perf/util/util.h
+++ b/tools/perf/util/util.h
@@ -253,7 +253,7 @@
 int strtailcmp(const char *s1, const char *s2);
 char *strxfrchar(char *s, char from, char to);
 unsigned long convert_unit(unsigned long value, char *unit);
-int readn(int fd, void *buf, size_t size);
+ssize_t readn(int fd, void *buf, size_t n);
 
 struct perf_event_attr;