Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...

[firefly-linux-kernel-4.4.55.git] / kernel / events / core.c

diff --git a/kernel/events/core.c b/kernel/events/core.c
index ef2d6ea10736e4805e758cae83524dc13c2f06e9..cfc227ccfcebc6e6843cf3e1c7edc5931d69e397 100644 (file)
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -3154,15 +3154,16 @@ static int event_enable_on_exec(struct perf_event *event,
  * Enable all of a task's events that have been marked enable-on-exec.
  * This expects task == current.
  */
-static void perf_event_enable_on_exec(struct perf_event_context *ctx)
+static void perf_event_enable_on_exec(int ctxn)
 {
-       struct perf_event_context *clone_ctx = NULL;
+       struct perf_event_context *ctx, *clone_ctx = NULL;
        struct perf_event *event;
        unsigned long flags;
        int enabled = 0;
        int ret;
 
        local_irq_save(flags);
+       ctx = current->perf_event_ctxp[ctxn];
        if (!ctx || !ctx->nr_events)
                goto out;
 
@@ -3205,17 +3206,11 @@ out:
 
 void perf_event_exec(void)
 {
-       struct perf_event_context *ctx;
        int ctxn;
 
        rcu_read_lock();
-       for_each_task_context_nr(ctxn) {
-               ctx = current->perf_event_ctxp[ctxn];
-               if (!ctx)
-                       continue;
-
-               perf_event_enable_on_exec(ctx);
-       }
+       for_each_task_context_nr(ctxn)
+               perf_event_enable_on_exec(ctxn);
        rcu_read_unlock();
 }
 
@@ -6493,9 +6488,6 @@ struct swevent_htable {
 
        /* Recursion avoidance in each contexts */
        int                             recursion[PERF_NR_CONTEXTS];
-
-       /* Keeps track of cpu being initialized/exited */
-       bool                            online;
 };
 
 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
@@ -6753,14 +6745,8 @@ static int perf_swevent_add(struct perf_event *event, int flags)
        hwc->state = !(flags & PERF_EF_START);
 
        head = find_swevent_head(swhash, event);
-       if (!head) {
-               /*
-                * We can race with cpu hotplug code. Do not
-                * WARN if the cpu just got unplugged.
-                */
-               WARN_ON_ONCE(swhash->online);
+       if (WARN_ON_ONCE(!head))
                return -EINVAL;
-       }
 
        hlist_add_head_rcu(&event->hlist_entry, head);
        perf_event_update_userpage(event);
@@ -6828,7 +6814,6 @@ static int swevent_hlist_get_cpu(struct perf_event *event, int cpu)
        int err = 0;
 
        mutex_lock(&swhash->hlist_mutex);
-
        if (!swevent_hlist_deref(swhash) && cpu_online(cpu)) {
                struct swevent_hlist *hlist;
 
@@ -9291,7 +9276,6 @@ static void perf_event_init_cpu(int cpu)
        struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
 
        mutex_lock(&swhash->hlist_mutex);
-       swhash->online = true;
        if (swhash->hlist_refcount > 0) {
                struct swevent_hlist *hlist;
 
@@ -9333,14 +9317,7 @@ static void perf_event_exit_cpu_context(int cpu)
 
 static void perf_event_exit_cpu(int cpu)
 {
-       struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
-
        perf_event_exit_cpu_context(cpu);
-
-       mutex_lock(&swhash->hlist_mutex);
-       swhash->online = false;
-       swevent_hlist_release(swhash);
-       mutex_unlock(&swhash->hlist_mutex);
 }
 #else
 static inline void perf_event_exit_cpu(int cpu) { }