Pure cleanup, no functional change. Replace 'volatile int iterate_on' with plain int and explicit READ_ONCE/WRITE_ONCE at each access site. This is more idiomatic for kernel code and documents the intent at the point of use rather than at the declaration.
https://virtuozzo.atlassian.net/browse/VSTOR-127669 Feature: fix selftests Signed-off-by: Eva Kurchatova <[email protected]> Signed-off-by: Konstantin Khorenko <[email protected]> --- .../selftests/perf_events/sigtrap_threads.c | 24 +++++++++++-------- 1 file changed, 14 insertions(+), 10 deletions(-) diff --git a/tools/testing/selftests/perf_events/sigtrap_threads.c b/tools/testing/selftests/perf_events/sigtrap_threads.c index 6b246e0ffde9..840d5f452d54 100644 --- a/tools/testing/selftests/perf_events/sigtrap_threads.c +++ b/tools/testing/selftests/perf_events/sigtrap_threads.c @@ -35,11 +35,15 @@ #define NUM_THREADS 5 +/* Force watchpoint access to actually occur. */ +#define READ_ONCE(x) (*(volatile typeof(x) *)&(x)) +#define WRITE_ONCE(x, val) (*(volatile typeof(x) *)&(x) = (val)) + /* Data shared between test body, threads, and signal handler. */ static struct { int tids_want_signal; /* Which threads still want a signal. */ int signal_count; /* Sanity check number of signals received. */ - volatile int iterate_on; /* Variable to set breakpoint on. */ + int iterate_on; /* Variable to set breakpoint on. */ siginfo_t first_siginfo; /* First observed siginfo_t. */ } ctx; @@ -94,14 +98,14 @@ static void *test_thread(void *arg) pthread_barrier_wait(barrier); __atomic_fetch_add(&ctx.tids_want_signal, tid, __ATOMIC_RELAXED); - iter = ctx.iterate_on; /* read */ + iter = READ_ONCE(ctx.iterate_on); if (iter >= 0) { for (i = 0; i < iter - 1; i++) { __atomic_fetch_add(&ctx.tids_want_signal, tid, __ATOMIC_RELAXED); - ctx.iterate_on = iter; /* idempotent write */ + WRITE_ONCE(ctx.iterate_on, iter); /* idempotent write */ } } else { - while (ctx.iterate_on); + while (READ_ONCE(ctx.iterate_on)); } return NULL; @@ -175,7 +179,7 @@ TEST_F(sigtrap_threads, enable_event) EXPECT_EQ(ctx.first_siginfo.si_perf_data, TEST_SIG_DATA(&ctx.iterate_on, 0)); /* Check enabled for parent. */ - ctx.iterate_on = 0; + WRITE_ONCE(ctx.iterate_on, 0); EXPECT_EQ(__atomic_load_n(&ctx.signal_count, __ATOMIC_RELAXED), NUM_THREADS + 1); } @@ -194,20 +198,20 @@ TEST_F(sigtrap_threads, modify_and_enable_event) EXPECT_EQ(ctx.first_siginfo.si_perf_data, TEST_SIG_DATA(&ctx.iterate_on, 42)); /* Check enabled for parent. */ - ctx.iterate_on = 0; + WRITE_ONCE(ctx.iterate_on, 0); EXPECT_EQ(__atomic_load_n(&ctx.signal_count, __ATOMIC_RELAXED), NUM_THREADS + 1); } /* Stress test event + signal handling. */ TEST_F(sigtrap_threads, signal_stress) { - ctx.iterate_on = 3000; + WRITE_ONCE(ctx.iterate_on, 3000); EXPECT_EQ(ioctl(self->fd, PERF_EVENT_IOC_ENABLE, 0), 0); run_test_threads(_metadata, self); EXPECT_EQ(ioctl(self->fd, PERF_EVENT_IOC_DISABLE, 0), 0); - EXPECT_EQ(__atomic_load_n(&ctx.signal_count, __ATOMIC_RELAXED), NUM_THREADS * ctx.iterate_on); + EXPECT_EQ(__atomic_load_n(&ctx.signal_count, __ATOMIC_RELAXED), NUM_THREADS * READ_ONCE(ctx.iterate_on)); EXPECT_EQ(__atomic_load_n(&ctx.tids_want_signal, __ATOMIC_RELAXED), 0); EXPECT_EQ(ctx.first_siginfo.si_addr, &ctx.iterate_on); EXPECT_EQ(ctx.first_siginfo.si_perf_type, PERF_TYPE_BREAKPOINT); @@ -219,7 +223,7 @@ TEST_F(sigtrap_threads, signal_stress_with_disable) const int target_count = NUM_THREADS * 3000; int i; - ctx.iterate_on = -1; + WRITE_ONCE(ctx.iterate_on, -1); EXPECT_EQ(ioctl(self->fd, PERF_EVENT_IOC_ENABLE, 0), 0); pthread_barrier_wait(&self->barrier); @@ -227,7 +231,7 @@ TEST_F(sigtrap_threads, signal_stress_with_disable) EXPECT_EQ(ioctl(self->fd, PERF_EVENT_IOC_DISABLE, 0), 0); EXPECT_EQ(ioctl(self->fd, PERF_EVENT_IOC_ENABLE, 0), 0); } - ctx.iterate_on = 0; + WRITE_ONCE(ctx.iterate_on, 0); for (i = 0; i < NUM_THREADS; i++) ASSERT_EQ(pthread_join(self->threads[i], NULL), 0); EXPECT_EQ(ioctl(self->fd, PERF_EVENT_IOC_DISABLE, 0), 0); -- 2.54.0
