[RFC v2 4/6] dmabuf: heaps: export system_heap buffers with GPU cgroup charging

["T.J. Mercier" <tjmercier@google.com>]

All DMA heaps now register a new GPU cgroup device upon creation, and the
system_heap now exports buffers associated with its GPU cgroup device for
tracking purposes.

From: Hridya Valsaraju <hridya@google.com>
Signed-off-by: Hridya Valsaraju <hridya@google.com>
Co-developed-by: T.J. Mercier <tjmercier@google.com>
Signed-off-by: T.J. Mercier <tjmercier@google.com>
---
changes in v2
- Move dma-buf cgroup charge transfer from a dma_buf_op defined by every
heap to a single dma-buf function for all heaps per Daniel Vetter and
Christian König.

 drivers/dma-buf/dma-heap.c          | 27 +++++++++++++++++++++++++++
 drivers/dma-buf/heaps/system_heap.c |  3 +++
 include/linux/dma-heap.h            | 11 +++++++++++
 3 files changed, 41 insertions(+)

diff --git a/drivers/dma-buf/dma-heap.c b/drivers/dma-buf/dma-heap.c
index 8f5848aa144f..885072427775 100644
--- a/drivers/dma-buf/dma-heap.c
+++ b/drivers/dma-buf/dma-heap.c
@@ -7,6 +7,7 @@
  */
 
 #include <linux/cdev.h>
+#include <linux/cgroup_gpu.h>
 #include <linux/debugfs.h>
 #include <linux/device.h>
 #include <linux/dma-buf.h>
@@ -31,6 +32,7 @@
  * @heap_devt		heap device node
  * @list		list head connecting to list of heaps
  * @heap_cdev		heap char device
+ * @gpucg_dev		gpu cgroup device for memory accounting
  *
  * Represents a heap of memory from which buffers can be made.
  */
@@ -41,6 +43,9 @@ struct dma_heap {
 	dev_t heap_devt;
 	struct list_head list;
 	struct cdev heap_cdev;
+#ifdef CONFIG_CGROUP_GPU
+	struct gpucg_device gpucg_dev;
+#endif
 };
 
 static LIST_HEAD(heap_list);
@@ -216,6 +221,26 @@ const char *dma_heap_get_name(struct dma_heap *heap)
 	return heap->name;
 }
 
+#ifdef CONFIG_CGROUP_GPU
+/**
+ * dma_heap_get_gpucg_dev() - get struct gpucg_device for the heap.
+ * @heap: DMA-Heap to get the gpucg_device struct for.
+ *
+ * Returns:
+ * The gpucg_device struct for the heap. NULL if the GPU cgroup controller is
+ * not enabled.
+ */
+struct gpucg_device *dma_heap_get_gpucg_dev(struct dma_heap *heap)
+{
+	return &heap->gpucg_dev;
+}
+#else /* CONFIG_CGROUP_GPU */
+struct gpucg_device *dma_heap_get_gpucg_dev(struct dma_heap *heap)
+{
+	return NULL;
+}
+#endif /* CONFIG_CGROUP_GPU */
+
 struct dma_heap *dma_heap_add(const struct dma_heap_export_info *exp_info)
 {
 	struct dma_heap *heap, *h, *err_ret;
@@ -288,6 +313,8 @@ struct dma_heap *dma_heap_add(const struct dma_heap_export_info *exp_info)
 	list_add(&heap->list, &heap_list);
 	mutex_unlock(&heap_list_lock);
 
+	gpucg_register_device(dma_heap_get_gpucg_dev(heap), exp_info->name);
+
 	return heap;
 
 err2:
diff --git a/drivers/dma-buf/heaps/system_heap.c b/drivers/dma-buf/heaps/system_heap.c
index ab7fd896d2c4..752a05c3cfe2 100644
--- a/drivers/dma-buf/heaps/system_heap.c
+++ b/drivers/dma-buf/heaps/system_heap.c
@@ -395,6 +395,9 @@ static struct dma_buf *system_heap_allocate(struct dma_heap *heap,
 	exp_info.ops = &system_heap_buf_ops;
 	exp_info.size = buffer->len;
 	exp_info.flags = fd_flags;
+#ifdef CONFIG_CGROUP_GPU
+	exp_info.gpucg_dev = dma_heap_get_gpucg_dev(heap);
+#endif
 	exp_info.priv = buffer;
 	dmabuf = dma_buf_export(&exp_info);
 	if (IS_ERR(dmabuf)) {
diff --git a/include/linux/dma-heap.h b/include/linux/dma-heap.h
index 0c05561cad6e..e447a61d054e 100644
--- a/include/linux/dma-heap.h
+++ b/include/linux/dma-heap.h
@@ -10,6 +10,7 @@
 #define _DMA_HEAPS_H
 
 #include <linux/cdev.h>
+#include <linux/cgroup_gpu.h>
 #include <linux/types.h>
 
 struct dma_heap;
@@ -59,6 +60,16 @@ void *dma_heap_get_drvdata(struct dma_heap *heap);
  */
 const char *dma_heap_get_name(struct dma_heap *heap);
 
+/**
+ * dma_heap_get_gpucg_dev() - get a pointer to the struct gpucg_device for the
+ * heap.
+ * @heap: DMA-Heap to retrieve gpucg_device for.
+ *
+ * Returns:
+ * The gpucg_device struct for the heap.
+ */
+struct gpucg_device *dma_heap_get_gpucg_dev(struct dma_heap *heap);
+
 /**
  * dma_heap_add - adds a heap to dmabuf heaps
  * @exp_info:		information needed to register this heap
-- 
2.35.1.265.g69c8d7142f-goog