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bpf, selftests: fix handling of sparse CPU allocations
[ Upstream commit 1bb54c4071
]
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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
parent
167a0989ec
commit
3084058a72
1 changed files with 21 additions and 11 deletions
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@ -13,7 +13,7 @@ static inline unsigned int bpf_num_possible_cpus(void)
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unsigned int start, end, possible_cpus = 0;
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char buff[128];
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FILE *fp;
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int n;
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int len, n, i, j = 0;
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fp = fopen(fcpu, "r");
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if (!fp) {
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@ -21,17 +21,27 @@ static inline unsigned int bpf_num_possible_cpus(void)
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exit(1);
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}
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while (fgets(buff, sizeof(buff), fp)) {
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n = sscanf(buff, "%u-%u", &start, &end);
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if (n == 0) {
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if (!fgets(buff, sizeof(buff), fp)) {
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printf("Failed to read %s!\n", fcpu);
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exit(1);
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}
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len = strlen(buff);
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for (i = 0; i <= len; i++) {
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if (buff[i] == ',' || buff[i] == '\0') {
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buff[i] = '\0';
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n = sscanf(&buff[j], "%u-%u", &start, &end);
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if (n <= 0) {
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printf("Failed to retrieve # possible CPUs!\n");
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exit(1);
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} else if (n == 1) {
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end = start;
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}
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possible_cpus = start == 0 ? end + 1 : 0;
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break;
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possible_cpus += end - start + 1;
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j = i + 1;
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}
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}
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fclose(fp);
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return possible_cpus;
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