[RFC][PATCH 2/2] dma-buf: heaps: Allow system & cma heaps to be configured as a modules

John Stultz john.stultz at linaro.org
Fri Oct 25 23:48:34 UTC 2019

Allow loading system and cma heap as a module instead of just as
a statically built in heap.

Since there isn't a good mechanism for dmabuf lifetime tracking
it isn't safe to allow the heap drivers to be unloaded, so these
drivers do not implement any module unloading functionality and
will show up in lsmod as "[permanent]".

This patch also exports key functions from dmabuf heaps core and
the heap helper functions so they can be accessed by the module.

Cc: Laura Abbott <labbott at redhat.com>
Cc: Benjamin Gaignard <benjamin.gaignard at linaro.org>
Cc: Sumit Semwal <sumit.semwal at linaro.org>
Cc: Liam Mark <lmark at codeaurora.org>
Cc: Pratik Patel <pratikp at codeaurora.org>
Cc: Brian Starkey <Brian.Starkey at arm.com>
Cc: Andrew F. Davis <afd at ti.com>
Cc: Andrew Morton <akpm at linux-foundation.org>
Cc: Yue Hu <huyue2 at yulong.com>
Cc: Mike Rapoport <rppt at linux.ibm.com>
Cc: Chenbo Feng <fengc at google.com>
Cc: Alistair Strachan <astrachan at google.com>
Cc: Sandeep Patil <sspatil at google.com>
Cc: Hridya Valsaraju <hridya at google.com>
Cc: dri-devel at lists.freedesktop.org
Signed-off-by: John Stultz <john.stultz at linaro.org>
 drivers/dma-buf/dma-heap.c           | 2 ++
 drivers/dma-buf/heaps/Kconfig        | 4 ++--
 drivers/dma-buf/heaps/heap-helpers.c | 2 ++
 3 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/dma-buf/dma-heap.c b/drivers/dma-buf/dma-heap.c
index 9a41b73e54b4..2c4ac71a715b 100644
--- a/drivers/dma-buf/dma-heap.c
+++ b/drivers/dma-buf/dma-heap.c
@@ -161,6 +161,7 @@ void *dma_heap_get_drvdata(struct dma_heap *heap)
 	return heap->priv;
 struct dma_heap *dma_heap_add(const struct dma_heap_export_info *exp_info)
@@ -243,6 +244,7 @@ struct dma_heap *dma_heap_add(const struct dma_heap_export_info *exp_info)
 	return err_ret;
 static char *dma_heap_devnode(struct device *dev, umode_t *mode)
diff --git a/drivers/dma-buf/heaps/Kconfig b/drivers/dma-buf/heaps/Kconfig
index a5eef06c4226..e273fb18feca 100644
--- a/drivers/dma-buf/heaps/Kconfig
+++ b/drivers/dma-buf/heaps/Kconfig
@@ -1,12 +1,12 @@
-	bool "DMA-BUF System Heap"
+	tristate "DMA-BUF System Heap"
 	depends on DMABUF_HEAPS
 	  Choose this option to enable the system dmabuf heap. The system heap
 	  is backed by pages from the buddy allocator. If in doubt, say Y.
-	bool "DMA-BUF CMA Heap"
+	tristate "DMA-BUF CMA Heap"
 	depends on DMABUF_HEAPS && DMA_CMA
 	  Choose this option to enable dma-buf CMA heap. This heap is backed
diff --git a/drivers/dma-buf/heaps/heap-helpers.c b/drivers/dma-buf/heaps/heap-helpers.c
index 750bef4e902d..fb9835126893 100644
--- a/drivers/dma-buf/heaps/heap-helpers.c
+++ b/drivers/dma-buf/heaps/heap-helpers.c
@@ -24,6 +24,7 @@ void init_heap_helper_buffer(struct heap_helper_buffer *buffer,
 	buffer->free = free;
 struct dma_buf *heap_helper_export_dmabuf(struct heap_helper_buffer *buffer,
 					  int fd_flags)
@@ -37,6 +38,7 @@ struct dma_buf *heap_helper_export_dmabuf(struct heap_helper_buffer *buffer,
 	return dma_buf_export(&exp_info);
 static void *dma_heap_map_kernel(struct heap_helper_buffer *buffer)

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