selftests/bpf: Make bpf_util work on uniprocessor systems

The current implementation fails to work on uniprocessor systems.
Fix the parser to also handle the uniprocessor case.

Signed-off-by: Thomas Meyer <thomas@m3y3r.de>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>

diff --git a/tools/testing/selftests/bpf/bpf_util.h b/tools/testing/selftests/bpf/bpf_util.h
index 20ecbaa0d85d72b860678caf49c3e421105802b8..6c53a8906eff4c4fe6d98863050132d928de50f8 100644 (file)
--- a/tools/testing/selftests/bpf/bpf_util.h
+++ b/tools/testing/selftests/bpf/bpf_util.h
@@ -12,6 +12,7 @@ static inline unsigned int bpf_num_possible_cpus(void)
        unsigned int start, end, possible_cpus = 0;
        char buff[128];
        FILE *fp;
+       int n;
 
        fp = fopen(fcpu, "r");
        if (!fp) {
@@ -20,17 +21,17 @@ static inline unsigned int bpf_num_possible_cpus(void)
        }
 
        while (fgets(buff, sizeof(buff), fp)) {
-               if (sscanf(buff, "%u-%u", &start, &end) == 2) {
-                       possible_cpus = start == 0 ? end + 1 : 0;
-                       break;
+               n = sscanf(buff, "%u-%u", &start, &end);
+               if (n == 0) {
+                       printf("Failed to retrieve # possible CPUs!\n");
+                       exit(1);
+               } else if (n == 1) {
+                       end = start;
                }
+               possible_cpus = start == 0 ? end + 1 : 0;
+               break;
        }
-
        fclose(fp);
-       if (!possible_cpus) {
-               printf("Failed to retrieve # possible CPUs!\n");
-               exit(1);
-       }
 
        return possible_cpus;
 }