#include #include "util.h" #include "../perf.h" #include "cloexec.h" #include "asm/bug.h" #include "debug.h" #include #include #include static unsigned long flag = PERF_FLAG_FD_CLOEXEC; int __weak sched_getcpu(void) { #ifdef __NR_getcpu unsigned cpu; int err = syscall(__NR_getcpu, &cpu, NULL, NULL); if (!err) return cpu; #else errno = ENOSYS; #endif return -1; } static int perf_flag_probe(void) { /* use 'safest' configuration as used in perf_evsel__fallback() */ struct perf_event_attr attr = { .type = PERF_TYPE_SOFTWARE, .config = PERF_COUNT_SW_CPU_CLOCK, .exclude_kernel = 1, }; int fd; int err; int cpu; pid_t pid = -1; char sbuf[STRERR_BUFSIZE]; cpu = sched_getcpu(); if (cpu < 0) cpu = 0; /* * Using -1 for the pid is a workaround to avoid gratuitous jump label * changes. */ while (1) { /* check cloexec flag */ fd = sys_perf_event_open(&attr, pid, cpu, -1, PERF_FLAG_FD_CLOEXEC); if (fd < 0 && pid == -1 && errno == EACCES) { pid = 0; continue; } break; } err = errno; if (fd >= 0) { close(fd); return 1; } WARN_ONCE(err != EINVAL && err != EBUSY, "perf_event_open(..., PERF_FLAG_FD_CLOEXEC) failed with unexpected error %d (%s)\n", err, str_error_r(err, sbuf, sizeof(sbuf))); /* not supported, confirm error related to PERF_FLAG_FD_CLOEXEC */ while (1) { fd = sys_perf_event_open(&attr, pid, cpu, -1, 0); if (fd < 0 && pid == -1 && errno == EACCES) { pid = 0; continue; } break; } err = errno; if (fd >= 0) close(fd); if (WARN_ONCE(fd < 0 && err != EBUSY, "perf_event_open(..., 0) failed unexpectedly with error %d (%s)\n", err, str_error_r(err, sbuf, sizeof(sbuf)))) return -1; return 0; } unsigned long perf_event_open_cloexec_flag(void) { static bool probed; if (!probed) { if (perf_flag_probe() <= 0) flag = 0; probed = true; } return flag; } -next.git/commit/net/sctp/probe.c?h=nds-private-remove&id=6e7bc478c9a006c701c14476ec9d389a484b4864'>commitdiff

path: root/net/sctp/probe.c

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