From fc1310ebf8fe25ea7b983400e6fa41f5a6d11966 Mon Sep 17 00:00:00 2001
From: John Stultz <john.stultz@linaro.org>
Date: Tue, 5 May 2020 18:31:37 +0000
Subject: [PATCH] ANDROID: dma-heap: Refactor code to allow for future
 in-kernel users

Refactor the code to make in-kernel use a bit more clean.

Signed-off-by: John Stultz <john.stultz@linaro.org>
Change-Id: I909a36ea6f2351415decbd489fd71ea03b2c2171
Bug: 154341375
---
 drivers/dma-buf/dma-heap.c | 44 ++++++++++++++++++++++++--------------
 1 file changed, 28 insertions(+), 16 deletions(-)

diff --git a/drivers/dma-buf/dma-heap.c b/drivers/dma-buf/dma-heap.c
index 6b6cefa7f597..a64a802003a8 100644
--- a/drivers/dma-buf/dma-heap.c
+++ b/drivers/dma-buf/dma-heap.c
@@ -50,10 +50,31 @@ static dev_t dma_heap_devt;
 static struct class *dma_heap_class;
 static DEFINE_XARRAY_ALLOC(dma_heap_minors);
 
+static struct dma_heap *dma_heap_find(const char *name)
+{
+	struct dma_heap *h;
+
+	mutex_lock(&heap_list_lock);
+	list_for_each_entry(h, &heap_list, list) {
+		if (!strcmp(h->name, name)) {
+			kref_get(&h->refcount);
+			mutex_unlock(&heap_list_lock);
+			return h;
+		}
+	}
+	mutex_unlock(&heap_list_lock);
+	return NULL;
+}
+
 static int dma_heap_buffer_alloc(struct dma_heap *heap, size_t len,
 				 unsigned int fd_flags,
 				 unsigned int heap_flags)
 {
+	if (fd_flags & ~DMA_HEAP_VALID_FD_FLAGS)
+		return -EINVAL;
+
+	if (heap_flags & ~DMA_HEAP_VALID_HEAP_FLAGS)
+		return -EINVAL;
 	/*
 	 * Allocations from all heaps have to begin
 	 * and end on page boundaries.
@@ -91,12 +112,6 @@ static long dma_heap_ioctl_allocate(struct file *file, void *data)
 	if (heap_allocation->fd)
 		return -EINVAL;
 
-	if (heap_allocation->fd_flags & ~DMA_HEAP_VALID_FD_FLAGS)
-		return -EINVAL;
-
-	if (heap_allocation->heap_flags & ~DMA_HEAP_VALID_HEAP_FLAGS)
-		return -EINVAL;
-
 	fd = dma_heap_buffer_alloc(heap, heap_allocation->len,
 				   heap_allocation->fd_flags,
 				   heap_allocation->heap_flags);
@@ -219,7 +234,7 @@ void dma_heap_put(struct dma_heap *h)
 
 struct dma_heap *dma_heap_add(const struct dma_heap_export_info *exp_info)
 {
-	struct dma_heap *heap, *h, *err_ret;
+	struct dma_heap *heap, *err_ret;
 	struct device *dev_ret;
 	int ret;
 
@@ -234,16 +249,13 @@ struct dma_heap *dma_heap_add(const struct dma_heap_export_info *exp_info)
 	}
 
 	/* check the name is unique */
-	mutex_lock(&heap_list_lock);
-	list_for_each_entry(h, &heap_list, list) {
-		if (!strcmp(h->name, exp_info->name)) {
-			mutex_unlock(&heap_list_lock);
-			pr_err("dma_heap: Already registered heap named %s\n",
-			       exp_info->name);
-			return ERR_PTR(-EINVAL);
-		}
+	heap = dma_heap_find(exp_info->name);
+	if (heap) {
+		pr_err("dma_heap: Already registered heap named %s\n",
+		       exp_info->name);
+		dma_heap_put(heap);
+		return ERR_PTR(-EINVAL);
 	}
-	mutex_unlock(&heap_list_lock);
 
 	heap = kzalloc(sizeof(*heap), GFP_KERNEL);
 	if (!heap)