ext4: enable "punch hole" functionality

[pandora-kernel.git] / kernel / perf_event.c

diff --git a/kernel/perf_event.c b/kernel/perf_event.c
index 3472bb1..27960f1 100644 (file)
--- a/kernel/perf_event.c
+++ b/kernel/perf_event.c
@@ -145,7 +145,8 @@ static struct srcu_struct pmus_srcu;
  */
 int sysctl_perf_event_paranoid __read_mostly = 1;
 
-int sysctl_perf_event_mlock __read_mostly = 512; /* 'free' kb per user */
+/* Minimum for 512 kiB + 1 user control page */
+int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024); /* 'free' kiB per user */
 
 /*
  * max perf event sample rate
@@ -941,6 +942,7 @@ static void perf_group_attach(struct perf_event *event)
 static void
 list_del_event(struct perf_event *event, struct perf_event_context *ctx)
 {
+       struct perf_cpu_context *cpuctx;
        /*
         * We can have double detach due to exit/hot-unplug + close.
         */
@@ -949,8 +951,17 @@ list_del_event(struct perf_event *event, struct perf_event_context *ctx)
 
        event->attach_state &= ~PERF_ATTACH_CONTEXT;
 
-       if (is_cgroup_event(event))
+       if (is_cgroup_event(event)) {
                ctx->nr_cgroups--;
+               cpuctx = __get_cpu_context(ctx);
+               /*
+                * if there are no more cgroup events
+                * then cler cgrp to avoid stale pointer
+                * in update_cgrp_time_from_cpuctx()
+                */
+               if (!ctx->nr_cgroups)
+                       cpuctx->cgrp = NULL;
+       }
 
        ctx->nr_events--;
        if (event->attr.inherit_stat)
@@ -6520,6 +6531,11 @@ SYSCALL_DEFINE5(perf_event_open,
                goto err_alloc;
        }
 
+       if (task) {
+               put_task_struct(task);
+               task = NULL;
+       }
+
        /*
         * Look up the group leader (we will attach this event to it):
         */