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>

diff --git a/tools/bpf/bpftool/common.c b/tools/bpf/bpftool/common.c
index f7261fad45c19cd7859d8d68d87aa26eb71ff128..5215e0870bcbaf84e97db8c241260989ed74318f 100644 (file)
--- 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 *

diff --git a/tools/testing/selftests/bpf/bpf_util.h b/tools/testing/selftests/bpf/bpf_util.h
index a29206ebbd1303cd60e9300d57b8ab12514959be..ec219f84e0415715c0d572e209f39f706587d0b5 100644 (file)
--- a/tools/testing/selftests/bpf/bpf_util.h
+++ b/tools/testing/selftests/bpf/bpf_util.h
@@ -6,44 +6,17 @@
 #include <stdlib.h>
 #include <string.h>
 #include <errno.h>
+#include <libbpf.h> /* libbpf_num_possible_cpus */
 
 static inline unsigned int bpf_num_possible_cpus(void)
 {
-       static const char *fcpu = "/sys/devices/system/cpu/possible";
-       unsigned int start, end, possible_cpus = 0;
-       char buff[128];
-       FILE *fp;
-       int len, n, i, j = 0;
+       int possible_cpus = libbpf_num_possible_cpus();
 
-       fp = fopen(fcpu, "r");
-       if (!fp) {
-               printf("Failed to open %s: '%s'!\n", fcpu, strerror(errno));
+       if (possible_cpus < 0) {
+               printf("Failed to get # of possible cpus: '%s'!\n",
+                      strerror(-possible_cpus));
                exit(1);
        }
-
-       if (!fgets(buff, sizeof(buff), fp)) {
-               printf("Failed to read %s!\n", fcpu);
-               exit(1);
-       }
-
-       len = strlen(buff);
-       for (i = 0; i <= len; i++) {
-               if (buff[i] == ',' || buff[i] == '\0') {
-                       buff[i] = '\0';
-                       n = sscanf(&buff[j], "%u-%u", &start, &end);
-                       if (n <= 0) {
-                               printf("Failed to retrieve # possible CPUs!\n");
-                               exit(1);
-                       } else if (n == 1) {
-                               end = start;
-                       }
-                       possible_cpus += end - start + 1;
-                       j = i + 1;
-               }
-       }
-
-       fclose(fp);
-
        return possible_cpus;
 }