Port the following patch for ARM by Mark Rutland:
- 57ce9bb39b476accf8fba6e16aea67ed76ea523d
ARM: 6902/1: perf: Remove erroneous check on active_events
When initialising a PMU, there is a check to protect against races with
other CPUs filling all of the available event slots. Since armpmu_add
checks that an event can be scheduled, we do not need to do this at
initialisation time. Furthermore the current code is broken because it
assumes that atomic_inc_not_zero will unconditionally increment
active_counts and then tries to decrement it again on failure.
This patch removes the broken, redundant code.
Signed-off-by: Deng-Cheng Zhu <dczhu@xxxxxxxx>
Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxxxxxxxxxx>
Cc: David Daney <david.daney@xxxxxxxxxx>
---
arch/mips/kernel/perf_event_mipsxx.c | 5 -----
1 files changed, 0 insertions(+), 5 deletions(-)
diff --git a/arch/mips/kernel/perf_event_mipsxx.c b/arch/mips/kernel/perf_event_mipsxx.c
index ab4c761..b5d6b3f 100644
--- a/arch/mips/kernel/perf_event_mipsxx.c
+++ b/arch/mips/kernel/perf_event_mipsxx.c
@@ -621,11 +621,6 @@ static int mipspmu_event_init(struct perf_event *event)
return -ENODEV;
if (!atomic_inc_not_zero(&active_events)) {
- if (atomic_read(&active_events) > MIPS_MAX_HWEVENTS) {
- atomic_dec(&active_events);
- return -ENOSPC;
- }
-
mutex_lock(&pmu_reserve_mutex);
if (atomic_read(&active_events) == 0)
err = mipspmu_get_irq();
--
1.7.1
