bpf: use libbpf_num_possible_cpus internally

Use the newly added bpf_num_possible_cpus() in bpftool and selftests
and remove duplicate implementations.

Signed-off-by: Hechao Li <hechaol@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

1 files changed, 5 insertions, 48 deletions

diff --git a/tools/bpf/bpftool/common.c b/tools/bpf/bpftool/common.c
index f7261fad45c1..5215e0870bcb 100644
--- a/tools/bpf/bpftool/common.c
+++ b/tools/bpf/bpftool/common.c
@@ -21,6 +21,7 @@
 #include <sys/vfs.h>
 
 #include <bpf.h>
+#include <libbpf.h> /* libbpf_num_possible_cpus */
 
 #include "main.h"
 
@@ -439,57 +440,13 @@ unsigned int get_page_size(void)
 
 unsigned int get_possible_cpus(void)
 {
-	static unsigned int result;
-	char buf[128];
-	long int n;
-	char *ptr;
-	int fd;
-
-	if (result)
-		return result;
-
-	fd = open("/sys/devices/system/cpu/possible", O_RDONLY);
-	if (fd < 0) {
-		p_err("can't open sysfs possible cpus");
-		exit(-1);
-	}
-
-	n = read(fd, buf, sizeof(buf));
-	if (n < 2) {
-		p_err("can't read sysfs possible cpus");
-		exit(-1);
-	}
-	close(fd);
+	int cpus = libbpf_num_possible_cpus();
 
-	if (n == sizeof(buf)) {
-		p_err("read sysfs possible cpus overflow");
+	if (cpus < 0) {
+		p_err("Can't get # of possible cpus: %s", strerror(-cpus));
 		exit(-1);
 	}
-
-	ptr = buf;
-	n = 0;
-	while (*ptr && *ptr != '\n') {
-		unsigned int a, b;
-
-		if (sscanf(ptr, "%u-%u", &a, &b) == 2) {
-			n += b - a + 1;
-
-			ptr = strchr(ptr, '-') + 1;
-		} else if (sscanf(ptr, "%u", &a) == 1) {
-			n++;
-		} else {
-			assert(0);
-		}
-
-		while (isdigit(*ptr))
-			ptr++;
-		if (*ptr == ',')
-			ptr++;
-	}
-
-	result = n;
-
-	return result;
+	return cpus;
 }
 
 static char *