From 74653ccf231a3100dd03e16e7a4178868a37332e Mon Sep 17 00:00:00 2001 From: Deng-Cheng Zhu Date: Tue, 22 Nov 2011 03:28:46 +0800 Subject: [PATCH] MIPS/Perf-events: Remove erroneous check on active_events 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 Cc: Peter Zijlstra Cc: Paul Mackerras Cc: Ingo Molnar Cc: Arnaldo Carvalho de Melo Cc: David Daney Cc: Eyal Barzilay Cc: Zenon Fortuna Patchwork: https://patchwork.linux-mips.org/patch/3106/ Signed-off-by: Ralf Baechle --- arch/mips/kernel/perf_event_mipsxx.c | 5 ----- 1 file changed, 5 deletions(-) diff --git a/arch/mips/kernel/perf_event_mipsxx.c b/arch/mips/kernel/perf_event_mipsxx.c index ab4c761cfedc..b5d6b3fa5a41 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(); -- 2.39.5