#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; } uthor'>author
rs?id=5906374446386fd16fe562b042429d905d231ec3'>drivers
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authorLinus Torvalds <torvalds@linux-foundation.org>2017-01-27 12:41:46 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2017-01-27 12:41:46 -0800
commit5906374446386fd16fe562b042429d905d231ec3 (patch)
tree8e8a9f367d1aeba25c644d3fcf096ffc443c4c5a /drivers
parent2fb78e89405f4321b86274a0c24b30896dd50529 (diff)
parent57b59ed2e5b91e958843609c7884794e29e6c4cb (diff)
Merge branch 'for-linus-4.10' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs
Pull btrfs updates from Chris Mason: "Some fixes that we've collected from the list. We still have one more pending to nail down a regression in lzo compression, but I wanted to get this batch out the door" * 'for-linus-4.10' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs: Btrfs: remove ->{get, set}_acl() from btrfs_dir_ro_inode_operations Btrfs: disable xattr operations on subvolume directories Btrfs: remove old tree_root case in btrfs_read_locked_inode() Btrfs: fix truncate down when no_holes feature is enabled Btrfs: Fix deadlock between direct IO and fast fsync btrfs: fix false enospc error when truncating heavily reflinked file
Diffstat (limited to 'drivers')