[Linaro-mm-sig] Re: [PATCH v3 1/6] dma-buf: dma-heap: Keep track of the heap device struct

On 3/6/26 4:36 AM, Albert Esteve wrote:

From: John Stultz john.stultz@linaro.org

Keep track of the heap device struct.

This will be useful for special DMA allocations and actions.

Signed-off-by: John Stultz john.stultz@linaro.org Reviewed-by: Maxime Ripard mripard@kernel.org Signed-off-by: Albert Esteve aesteve@redhat.com

---

drivers/dma-buf/dma-heap.c | 34 ++++++++++++++++++++++++++-------- include/linux/dma-heap.h | 2 ++ 2 files changed, 28 insertions(+), 8 deletions(-)

diff --git a/drivers/dma-buf/dma-heap.c b/drivers/dma-buf/dma-heap.c index ac5f8685a6494..1124d63eb1398 100644 --- a/drivers/dma-buf/dma-heap.c +++ b/drivers/dma-buf/dma-heap.c @@ -31,6 +31,7 @@

• @heap_devt: heap device node
• @list: list head connecting to list of heaps
• @heap_cdev: heap char device

• • @heap_dev: heap device
  • Represents a heap of memory from which buffers can be made.
  */

@@ -41,6 +42,7 @@ struct dma_heap { dev_t heap_devt; struct list_head list; struct cdev heap_cdev;

• struct device *heap_dev; };

static LIST_HEAD(heap_list); @@ -223,6 +225,19 @@ const char *dma_heap_get_name(struct dma_heap *heap) } EXPORT_SYMBOL_NS_GPL(dma_heap_get_name, "DMA_BUF_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) +{

• return heap->heap_dev;

+} +EXPORT_SYMBOL_NS_GPL(dma_heap_get_dev, "DMA_BUF_HEAP");

• /**
  • dma_heap_add - adds a heap to dmabuf heaps
  • @exp_info: information needed to register this heap

@@ -230,7 +245,6 @@ EXPORT_SYMBOL_NS_GPL(dma_heap_get_name, "DMA_BUF_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;

@@ -272,14 +286,14 @@ 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; }

@@ -295,6 +309,10 @@ struct dma_heap *dma_heap_add(const struct dma_heap_export_info *exp_info) } }

• /* Make sure it doesn't disappear on us */
• heap->heap_dev = get_device(heap->heap_dev);

Is this actually something that matters or could happen? Seems you just remove it in the next patch anyway.

Andrew

/* Add heap to the list */ list_add(&heap->list, &heap_list); mutex_unlock(&heap_list_lock); diff --git a/include/linux/dma-heap.h b/include/linux/dma-heap.h index 648328a64b27e..493085e69b70e 100644 --- a/include/linux/dma-heap.h +++ b/include/linux/dma-heap.h @@ -12,6 +12,7 @@ #include <linux/types.h> struct dma_heap; +struct device; /**

• struct dma_heap_ops - ops to operate on a given heap

@@ -43,6 +44,7 @@ struct dma_heap_export_info { void *dma_heap_get_drvdata(struct dma_heap *heap); const char *dma_heap_get_name(struct dma_heap *heap); +struct device *dma_heap_get_dev(struct dma_heap *heap); struct dma_heap *dma_heap_add(const struct dma_heap_export_info *exp_info);