perf/x86/intel: Fix build warning in intel_pmu_drain_pebs_nhm()

[firefly-linux-kernel-4.4.55.git] / arch / x86 / kernel / cpu / perf_event_intel_ds.c

diff --git a/arch/x86/kernel/cpu/perf_event_intel_ds.c b/arch/x86/kernel/cpu/perf_event_intel_ds.c
index f364c13ddaa645b1a2c52e58b18682ac9dedfd01..54ff6ce519c1d58f62b8f0498bd739b455c4f799 100644 (file)
--- a/arch/x86/kernel/cpu/perf_event_intel_ds.c
+++ b/arch/x86/kernel/cpu/perf_event_intel_ds.c
@@ -944,7 +944,7 @@ static void intel_pmu_drain_pebs_nhm(struct pt_regs *iregs)
        struct perf_event *event = NULL;
        void *at, *top;
        u64 status = 0;
-       int bit, n;
+       int bit;
 
        if (!x86_pmu.pebs_active)
                return;
@@ -954,16 +954,16 @@ static void intel_pmu_drain_pebs_nhm(struct pt_regs *iregs)
 
        ds->pebs_index = ds->pebs_buffer_base;
 
-       n = (top - at) / x86_pmu.pebs_record_size;
-       if (n <= 0)
+       if (unlikely(at > top))
                return;
 
        /*
         * Should not happen, we program the threshold at 1 and do not
         * set a reset value.
         */
-       WARN_ONCE(n > x86_pmu.max_pebs_events,
-                 "Unexpected number of pebs records %d\n", n);
+       WARN_ONCE(top - at > x86_pmu.max_pebs_events * x86_pmu.pebs_record_size,
+                 "Unexpected number of pebs records %ld\n",
+                 (long)(top - at) / x86_pmu.pebs_record_size);
 
        for (; at < top; at += x86_pmu.pebs_record_size) {
                struct pebs_record_nhm *p = at;