gpu: nvgpu: mark thread stopped when it independently quits

It's technically possible for a thread to exit without first calling
nvgpu_thread_stop() in another, so mark the thread exit status from the
thread after it has finished instead of in nvgpu_thread_stop(). Do this
by starting the thread as a proxy function which calls the actual thread
function and then sets the flag.

Also, add a new flag to actually signify the running state because the
thread->task going null abruptly would break nvgpu_thread_stop().

This does not guarantee that the kernel thread itself has stopped, but
the function which can be considered as an "nvgpu thread" will be.

Change-Id: Ib911b02bd51342ddeb8e6b9533ef7943f2606d2d
Signed-off-by: Konsta Holtta <kholtta@nvidia.com>
Reviewed-on: http://git-master/r/1501571
Reviewed-by: Mahantesh Kumbar <mkumbar@nvidia.com>
Reviewed-by: Alex Waterman <alexw@nvidia.com>
Reviewed-by: svccoveritychecker <svccoveritychecker@nvidia.com>
GVS: Gerrit_Virtual_Submit
Reviewed-by: Vijayakumar Subbu <vsubbu@nvidia.com>

1 files changed, 15 insertions, 2 deletions

diff --git a/drivers/gpu/nvgpu/common/linux/thread.c b/drivers/gpu/nvgpu/common/linux/thread.c
index ef783bbe..fe3906eb 100644
--- a/drivers/gpu/nvgpu/common/linux/thread.c
+++ b/drivers/gpu/nvgpu/common/linux/thread.c
@@ -18,15 +18,28 @@
 
 #include <nvgpu/thread.h>
 
+int nvgpu_thread_proxy(void *threaddata)
+{
+        struct nvgpu_thread *thread = threaddata;
+        int ret = thread->fn(thread->data);
+
+        thread->running = false;
+        return ret;
+}
+
 int nvgpu_thread_create(struct nvgpu_thread *thread,
                 void *data,
                 int (*threadfn)(void *data), const char *name)
 {
-        struct task_struct *task = kthread_create(threadfn, data, name);
+        struct task_struct *task = kthread_create(nvgpu_thread_proxy,
+                        thread, name);
         if (IS_ERR(task))
                 return PTR_ERR(task);
 
         thread->task = task;
+        thread->fn = threadfn;
+        thread->data = data;
+        thread->running = true;
         wake_up_process(task);
         return 0;
 };
@@ -44,5 +57,5 @@ bool nvgpu_thread_should_stop(struct nvgpu_thread *thread)
 
 bool nvgpu_thread_is_running(struct nvgpu_thread *thread)
 {
-        return thread->task != NULL;
+        return ACCESS_ONCE(thread->running);
 };