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

Submitted by John Stultz on Oct. 25, 2019, 11:48 p.m.

Details

Message ID 20191025234834.28214-3-john.stultz@linaro.org
State New
Headers show
Series "Allow DMA BUF heaps to be loaded as modules" ( rev: 1 ) in DRI devel

Not browsing as part of any series.

Commit Message

John Stultz Oct. 25, 2019, 11:48 p.m.
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@redhat.com>
Cc: Benjamin Gaignard <benjamin.gaignard@linaro.org>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: Liam Mark <lmark@codeaurora.org>
Cc: Pratik Patel <pratikp@codeaurora.org>
Cc: Brian Starkey <Brian.Starkey@arm.com>
Cc: Andrew F. Davis <afd@ti.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Yue Hu <huyue2@yulong.com>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Chenbo Feng <fengc@google.com>
Cc: Alistair Strachan <astrachan@google.com>
Cc: Sandeep Patil <sspatil@google.com>
Cc: Hridya Valsaraju <hridya@google.com>
Cc: dri-devel@lists.freedesktop.org
Signed-off-by: John Stultz <john.stultz@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(-)

Patch hide | download patch | download mbox

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;
 }
+EXPORT_SYMBOL_GPL(dma_heap_get_drvdata);
 
 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)
 	kfree(heap);
 	return err_ret;
 }
+EXPORT_SYMBOL_GPL(dma_heap_add);
 
 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 @@ 
 config DMABUF_HEAPS_SYSTEM
-	bool "DMA-BUF System Heap"
+	tristate "DMA-BUF System Heap"
 	depends on DMABUF_HEAPS
 	help
 	  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.
 
 config DMABUF_HEAPS_CMA
-	bool "DMA-BUF CMA Heap"
+	tristate "DMA-BUF CMA Heap"
 	depends on DMABUF_HEAPS && DMA_CMA
 	help
 	  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,
 	INIT_LIST_HEAD(&buffer->attachments);
 	buffer->free = free;
 }
+EXPORT_SYMBOL_GPL(init_heap_helper_buffer);
 
 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);
 }
+EXPORT_SYMBOL_GPL(heap_helper_export_dmabuf);
 
 static void *dma_heap_map_kernel(struct heap_helper_buffer *buffer)
 {

Comments

Hi John,

On Fri, Oct 25, 2019 at 11:48:34PM +0000, John Stultz wrote:
> 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]".

Cool, that alleviates my concerns :-)

> 
> 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@redhat.com>
> Cc: Benjamin Gaignard <benjamin.gaignard@linaro.org>
> Cc: Sumit Semwal <sumit.semwal@linaro.org>
> Cc: Liam Mark <lmark@codeaurora.org>
> Cc: Pratik Patel <pratikp@codeaurora.org>
> Cc: Brian Starkey <Brian.Starkey@arm.com>
> Cc: Andrew F. Davis <afd@ti.com>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Yue Hu <huyue2@yulong.com>
> Cc: Mike Rapoport <rppt@linux.ibm.com>
> Cc: Chenbo Feng <fengc@google.com>
> Cc: Alistair Strachan <astrachan@google.com>
> Cc: Sandeep Patil <sspatil@google.com>
> Cc: Hridya Valsaraju <hridya@google.com>
> Cc: dri-devel@lists.freedesktop.org
> Signed-off-by: John Stultz <john.stultz@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;
>  }
> +EXPORT_SYMBOL_GPL(dma_heap_get_drvdata);
>  
>  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)
>  	kfree(heap);
>  	return err_ret;
>  }
> +EXPORT_SYMBOL_GPL(dma_heap_add);

Maybe overly picky - but adding the note about "no safe way to remove,
so there's no dma_heap_remove" to a comment on this function may be
easier to notice than in the git log alone.

Cheers,
-Brian

>  
>  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 @@
>  config DMABUF_HEAPS_SYSTEM
> -	bool "DMA-BUF System Heap"
> +	tristate "DMA-BUF System Heap"
>  	depends on DMABUF_HEAPS
>  	help
>  	  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.
>  
>  config DMABUF_HEAPS_CMA
> -	bool "DMA-BUF CMA Heap"
> +	tristate "DMA-BUF CMA Heap"
>  	depends on DMABUF_HEAPS && DMA_CMA
>  	help
>  	  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,
>  	INIT_LIST_HEAD(&buffer->attachments);
>  	buffer->free = free;
>  }
> +EXPORT_SYMBOL_GPL(init_heap_helper_buffer);
>  
>  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);
>  }
> +EXPORT_SYMBOL_GPL(heap_helper_export_dmabuf);
>  
>  static void *dma_heap_map_kernel(struct heap_helper_buffer *buffer)
>  {
> -- 
> 2.17.1
>
On Fri, Oct 25, 2019 at 11:48:34PM +0000, John Stultz wrote:
> 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]".

dma-buf itself has all the try_module_get we'll need ... why is this not
possible?
-Daniel

> 
> 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@redhat.com>
> Cc: Benjamin Gaignard <benjamin.gaignard@linaro.org>
> Cc: Sumit Semwal <sumit.semwal@linaro.org>
> Cc: Liam Mark <lmark@codeaurora.org>
> Cc: Pratik Patel <pratikp@codeaurora.org>
> Cc: Brian Starkey <Brian.Starkey@arm.com>
> Cc: Andrew F. Davis <afd@ti.com>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Yue Hu <huyue2@yulong.com>
> Cc: Mike Rapoport <rppt@linux.ibm.com>
> Cc: Chenbo Feng <fengc@google.com>
> Cc: Alistair Strachan <astrachan@google.com>
> Cc: Sandeep Patil <sspatil@google.com>
> Cc: Hridya Valsaraju <hridya@google.com>
> Cc: dri-devel@lists.freedesktop.org
> Signed-off-by: John Stultz <john.stultz@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;
>  }
> +EXPORT_SYMBOL_GPL(dma_heap_get_drvdata);
>  
>  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)
>  	kfree(heap);
>  	return err_ret;
>  }
> +EXPORT_SYMBOL_GPL(dma_heap_add);
>  
>  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 @@
>  config DMABUF_HEAPS_SYSTEM
> -	bool "DMA-BUF System Heap"
> +	tristate "DMA-BUF System Heap"
>  	depends on DMABUF_HEAPS
>  	help
>  	  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.
>  
>  config DMABUF_HEAPS_CMA
> -	bool "DMA-BUF CMA Heap"
> +	tristate "DMA-BUF CMA Heap"
>  	depends on DMABUF_HEAPS && DMA_CMA
>  	help
>  	  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,
>  	INIT_LIST_HEAD(&buffer->attachments);
>  	buffer->free = free;
>  }
> +EXPORT_SYMBOL_GPL(init_heap_helper_buffer);
>  
>  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);
>  }
> +EXPORT_SYMBOL_GPL(heap_helper_export_dmabuf);
>  
>  static void *dma_heap_map_kernel(struct heap_helper_buffer *buffer)
>  {
> -- 
> 2.17.1
> 
> _______________________________________________
> dri-devel mailing list
> dri-devel@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel
On Mon, Nov 4, 2019 at 2:24 AM Daniel Vetter <daniel@ffwll.ch> wrote:
> On Fri, Oct 25, 2019 at 11:48:34PM +0000, John Stultz wrote:
> > 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]".
>
> dma-buf itself has all the try_module_get we'll need ... why is this not
> possible?

Let me look into that.  Thanks for the pointer.

thanks
-john