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authorMartynas Pumputis <m@lambda.lt>2019-01-31 10:19:33 +0100
committerDaniel Borkmann <daniel@iogearbox.net>2019-01-31 23:13:22 +0100
commit1bb54c4071f585ebef56ce8fdfe6026fa2cbcddd (patch)
tree7250dc1999a2829c27b5e721446c49cad6b759f3 /tools
parent9d90436ece8f2c5b4da617e679590137e54ce4cb (diff)
bpf, selftests: fix handling of sparse CPU allocations
Previously, bpf_num_possible_cpus() had a bug when calculating a number of possible CPUs in the case of sparse CPU allocations, as it was considering only the first range or element of /sys/devices/system/cpu/possible. E.g. in the case of "0,2-3" (CPU 1 is not available), the function returned 1 instead of 3. This patch fixes the function by making it parse all CPU ranges and elements. Signed-off-by: Martynas Pumputis <m@lambda.lt> Acked-by: Yonghong Song <yhs@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Diffstat (limited to 'tools')
-rw-r--r--tools/testing/selftests/bpf/bpf_util.h30
1 files changed, 20 insertions, 10 deletions
diff --git a/tools/testing/selftests/bpf/bpf_util.h b/tools/testing/selftests/bpf/bpf_util.h
index 315a44fa32af..84fd6f1bf33e 100644
--- a/tools/testing/selftests/bpf/bpf_util.h
+++ b/tools/testing/selftests/bpf/bpf_util.h
@@ -13,7 +13,7 @@ static inline unsigned int bpf_num_possible_cpus(void)
unsigned int start, end, possible_cpus = 0;
char buff[128];
FILE *fp;
- int n;
+ int len, n, i, j = 0;
fp = fopen(fcpu, "r");
if (!fp) {
@@ -21,17 +21,27 @@ static inline unsigned int bpf_num_possible_cpus(void)
exit(1);
}
- while (fgets(buff, sizeof(buff), fp)) {
- 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;
+ 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;
}
- possible_cpus = start == 0 ? end + 1 : 0;
- break;
}
+
fclose(fp);
return possible_cpus;