perf: Find task before event alloc

So that we can pass the task pointer to the event allocation, so that
we can use task associated data during event initialization.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <20101014203625.340789919@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/kernel/perf_event.c b/kernel/perf_event.c
index f928878a1c17c173334b80e0cca4f38ddaefc08a..b21d06aaef60593bf05a9202fc6f1cef6efc6bb5 100644 (file)
--- a/kernel/perf_event.c
+++ b/kernel/perf_event.c
@@ -5551,10 +5551,18 @@ SYSCALL_DEFINE5(perf_event_open,
                        group_leader = NULL;
        }
 
+       if (pid != -1) {
+               task = find_lively_task_by_vpid(pid);
+               if (IS_ERR(task)) {
+                       err = PTR_ERR(task);
+                       goto err_group_fd;
+               }
+       }
+
        event = perf_event_alloc(&attr, cpu, group_leader, NULL, NULL);
        if (IS_ERR(event)) {
                err = PTR_ERR(event);
-               goto err_fd;
+               goto err_task;
        }
 
        /*
@@ -5586,21 +5594,13 @@ SYSCALL_DEFINE5(perf_event_open,
                }
        }
 
-       if (pid != -1) {
-               task = find_lively_task_by_vpid(pid);
-               if (IS_ERR(task)) {
-                       err = PTR_ERR(task);
-                       goto err_group_fd;
-               }
-       }
-
        /*
         * Get the target context (task or percpu):
         */
        ctx = find_get_context(pmu, task, cpu);
        if (IS_ERR(ctx)) {
                err = PTR_ERR(ctx);
-               goto err_task;
+               goto err_alloc;
        }
 
        /*
@@ -5696,12 +5696,13 @@ SYSCALL_DEFINE5(perf_event_open,
 
 err_context:
        put_ctx(ctx);
+err_alloc:
+       free_event(event);
 err_task:
        if (task)
                put_task_struct(task);
 err_group_fd:
        fput_light(group_file, fput_needed);
-       free_event(event);
 err_fd:
        put_unused_fd(event_fd);
        return err;