1 files changed, 18 insertions, 26 deletions

diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c
index e26d2fcfa320..3dd4339589a0 100644
--- a/kernel/perf_counter.c
+++ b/kernel/perf_counter.c
@@ -3444,40 +3444,32 @@ static void perf_swcounter_add(struct perf_counter *counter, u64 nr,
 
 static int perf_swcounter_is_counting(struct perf_counter *counter)
 {
-        struct perf_counter_context *ctx;
-        unsigned long flags;
-        int count;
-
+        /*
+         * The counter is active, we're good!
+         */
         if (counter->state == PERF_COUNTER_STATE_ACTIVE)
                 return 1;
 
+        /*
+         * The counter is off/error, not counting.
+         */
         if (counter->state != PERF_COUNTER_STATE_INACTIVE)
                 return 0;
 
         /*
-         * If the counter is inactive, it could be just because
-         * its task is scheduled out, or because it's in a group
-         * which could not go on the PMU.  We want to count in
-         * the first case but not the second.  If the context is
-         * currently active then an inactive software counter must
-         * be the second case.  If it's not currently active then
-         * we need to know whether the counter was active when the
-         * context was last active, which we can determine by
-         * comparing counter->tstamp_stopped with ctx->time.
-         *
-         * We are within an RCU read-side critical section,
-         * which protects the existence of *ctx.
+         * The counter is inactive, if the context is active
+         * we're part of a group that didn't make it on the 'pmu',
+         * not counting.
          */
-        ctx = counter->ctx;
-        spin_lock_irqsave(&ctx->lock, flags);
-        count = 1;
-        /* Re-check state now we have the lock */
-        if (counter->state < PERF_COUNTER_STATE_INACTIVE ||
-            counter->ctx->is_active ||
-            counter->tstamp_stopped < ctx->time)
-                count = 0;
-        spin_unlock_irqrestore(&ctx->lock, flags);
-        return count;
+        if (counter->ctx->is_active)
+                return 0;
+
+        /*
+         * We're inactive and the context is too, this means the
+         * task is scheduled out, we're counting events that happen
+         * to us, like migration events.
+         */
+        return 1;
 }
 
 static int perf_swcounter_match(struct perf_counter *counter,