android-mainline/ONHOLD-FROMLIST-dma-buf-dma-heap-Keep-track-of-the-heap-device-struct.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: John Stultz <john.stultz@linaro.org>
Date: Thu, 7 May 2020 20:08:13 +0000
Subject: ONHOLD: FROMLIST: dma-buf: dma-heap: Keep track of the heap device
 struct

Keep track of the heap device struct.

This will be useful for special DMA allocations
and actions.

[CPNOTE: 21/05/21] Lee: Requested status from John on the MLs
[CPNOTE: 26/05/21] Lee: No upstream user presently

Signed-off-by: John Stultz <john.stultz@linaro.org>
Link: https://lore.kernel.org/lkml/20201110034934.70898-7-john.stultz@linaro.org/
Bug: 170887642
Change-Id: I55b8df5fd9fd46795a8f0171318895297d2dd379
Signed-off-by: Hridya Valsaraju <hridya@google.com>
(cherry picked from commit 2501fd6245d8a1a408c7871c0fc8eb9e0116c944)
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
---
 drivers/dma-buf/dma-heap.c | 33 +++++++++++++++++++++++++--------
 include/linux/dma-heap.h   |  9 +++++++++
 2 files changed, 34 insertions(+), 8 deletions(-)

diff --git a/drivers/dma-buf/dma-heap.c b/drivers/dma-buf/dma-heap.c
--- a/drivers/dma-buf/dma-heap.c
+++ b/drivers/dma-buf/dma-heap.c
@@ -30,6 +30,7 @@
  * @heap_devt		heap device node
  * @list		list head connecting to list of heaps
  * @heap_cdev		heap char device
+ * @heap_dev		heap device struct
  *
  * Represents a heap of memory from which buffers can be made.
  */
@@ -40,6 +41,7 @@ struct dma_heap {
 	dev_t heap_devt;
 	struct list_head list;
 	struct cdev heap_cdev;
+	struct device *heap_dev;
 };
 
 static LIST_HEAD(heap_list);
@@ -202,6 +204,18 @@ void *dma_heap_get_drvdata(struct dma_heap *heap)
 	return heap->priv;
 }
 
+/**
+ * dma_heap_get_dev() - get device struct for the heap
+ * @heap: DMA-Heap to retrieve device struct from
+ *
+ * Returns:
+ * The device struct for the heap.
+ */
+struct device *dma_heap_get_dev(struct dma_heap *heap)
+{
+	return heap->heap_dev;
+}
+
 /**
  * dma_heap_get_name() - get heap name
  * @heap: DMA-Heap to retrieve private data for
@@ -217,7 +231,6 @@ const char *dma_heap_get_name(struct dma_heap *heap)
 struct dma_heap *dma_heap_add(const struct dma_heap_export_info *exp_info)
 {
 	struct dma_heap *heap, *h, *err_ret;
-	struct device *dev_ret;
 	unsigned int minor;
 	int ret;
 
@@ -271,16 +284,20 @@ struct dma_heap *dma_heap_add(const struct dma_heap_export_info *exp_info)
 		goto err1;
 	}
 
-	dev_ret = device_create(dma_heap_class,
-				NULL,
-				heap->heap_devt,
-				NULL,
-				heap->name);
-	if (IS_ERR(dev_ret)) {
+	heap->heap_dev = device_create(dma_heap_class,
+				       NULL,
+				       heap->heap_devt,
+				       NULL,
+				       heap->name);
+	if (IS_ERR(heap->heap_dev)) {
 		pr_err("dma_heap: Unable to create device\n");
-		err_ret = ERR_CAST(dev_ret);
+		err_ret = ERR_CAST(heap->heap_dev);
 		goto err2;
 	}
+
+	/* Make sure it doesn't disappear on us */
+	heap->heap_dev = get_device(heap->heap_dev);
+
 	/* Add heap to the list */
 	mutex_lock(&heap_list_lock);
 	list_add(&heap->list, &heap_list);
diff --git a/include/linux/dma-heap.h b/include/linux/dma-heap.h
--- a/include/linux/dma-heap.h
+++ b/include/linux/dma-heap.h
@@ -50,6 +50,15 @@ struct dma_heap_export_info {
  */
 void *dma_heap_get_drvdata(struct dma_heap *heap);
 
+/**
+ * dma_heap_get_dev() - get device struct for the heap
+ * @heap: DMA-Heap to retrieve device struct from
+ *
+ * Returns:
+ * The device struct for the heap.
+ */
+struct device *dma_heap_get_dev(struct dma_heap *heap);
+
 /**
  * dma_heap_get_name() - get heap name
  * @heap: DMA-Heap to retrieve private data for