From 6a78371acebfe1e9d9eda218a835d712193d35a5 Mon Sep 17 00:00:00 2001 From: Russell King Date: Thu, 19 Jun 2014 10:39:41 +0100 Subject: [PATCH] ARM: perf: fix compiler warning with gcc 4.6.4 (and tidy code) GCC 4.6.4 spits out the following warning when building perf_event_v7.c: arch/arm/kernel/perf_event_v7.c: In function 'krait_pmu_get_event_idx': arch/arm/kernel/perf_event_v7.c:1927:6: warning: 'bit' may be used uninitialized in this function While upgrading the version of gcc may solve this, the code can also be organised to be more efficient by not carrying more local variables than is necessary across the armv7pmu_get_event_idx function call. If we set 'bit' to -1 (which is invalid for clear_bit) we can use that as an indication whether we need to clear a bit after this function. Acked-by: Will Deacon Signed-off-by: Russell King --- arch/arm/kernel/perf_event_v7.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/arm/kernel/perf_event_v7.c b/arch/arm/kernel/perf_event_v7.c index 2037f7205987..1d37568c547a 100644 --- a/arch/arm/kernel/perf_event_v7.c +++ b/arch/arm/kernel/perf_event_v7.c @@ -1924,7 +1924,7 @@ static int krait_pmu_get_event_idx(struct pmu_hw_events *cpuc, struct perf_event *event) { int idx; - int bit; + int bit = -1; unsigned int prefix; unsigned int region; unsigned int code; @@ -1953,7 +1953,7 @@ static int krait_pmu_get_event_idx(struct pmu_hw_events *cpuc, } idx = armv7pmu_get_event_idx(cpuc, event); - if (idx < 0 && krait_event) + if (idx < 0 && bit >= 0) clear_bit(bit, cpuc->used_mask); return idx;