On Fri, Aug 07, 2015 at 11:50:13AM +0800, Feng Tang wrote:
> When trying to use several cma heaps on our platforms,
> we met a memory issue due to that the several cma_heaps
> are sharing the same "struct device *".
>
> As in current code base, the normal cma heap creating
> process is, one platform device is created during boot,
> and it will sequentially create cma heaps (usually passing
> its own struct device * as a parameter)
>
> For the multiple cma heaps case, there will be one "struct
> cma" created for each cma heap, and this "struct cma *" is
> saved in dev->cma_area. So the single platform device can't
> meet the requirement here.
>
> This patch adds one default device for each cma heap to avoid
> sharing the same "struct device", thus fix the issue. And it
> doesn't break existing code by only using that default device
> when no "struct device *" is passed in.
>
> Also, since the cma framework has been cleaned up recently,
> this patch also adds a platform data member to pass the
> "struct cma*" to ion_cma_heap_create().
>
> Signed-off-by: Feng Tang <feng.t...@intel.com>
> [From CMA’s point of view: ]
> Acked-by: Michal Nazarewicz <min...@mina86.com>
> ---
> drivers/staging/android/ion/ion.h | 4 ++++
> drivers/staging/android/ion/ion_cma_heap.c | 20 +++++++++++++++++---
> 2 files changed, 21 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/staging/android/ion/ion.h
> b/drivers/staging/android/ion/ion.h
> index 443db84..11336df 100644
> --- a/drivers/staging/android/ion/ion.h
> +++ b/drivers/staging/android/ion/ion.h
> @@ -44,6 +44,9 @@ struct ion_buffer;
> * @base: base address of heap in physical memory if applicable
> * @size: size of the heap in bytes if applicable
> * @align: required alignment in physical memory if applicable
> + * @cma: when creating CMA heap, platform device should better also
> + * pass the "struct cma *" info, so that the cma buffer request
> + * know where to go for the buffer
> * @priv: private info passed from the board file
> *
> * Provided by the board file.
> @@ -55,6 +58,7 @@ struct ion_platform_heap {
> ion_phys_addr_t base;
> size_t size;
> ion_phys_addr_t align;
> + struct cma *cma;
> void *priv;
> };
>
> diff --git a/drivers/staging/android/ion/ion_cma_heap.c
> b/drivers/staging/android/ion/ion_cma_heap.c
> index f4211f1..27f218a 100644
> --- a/drivers/staging/android/ion/ion_cma_heap.c
> +++ b/drivers/staging/android/ion/ion_cma_heap.c
> @@ -29,6 +29,7 @@
> struct ion_cma_heap {
> struct ion_heap heap;
> struct device *dev;
> + struct device default_dma_dev;
Why do we have 2 struct devices here?
> };
>
> #define to_cma_heap(x) container_of(x, struct ion_cma_heap, heap)
> @@ -180,9 +181,22 @@ struct ion_heap *ion_cma_heap_create(struct
> ion_platform_heap *data)
> return ERR_PTR(-ENOMEM);
>
> cma_heap->heap.ops = &ion_cma_ops;
> - /* get device from private heaps data, later it will be
> - * used to make the link with reserved CMA memory */
> - cma_heap->dev = data->priv;
> +
> + /*
> + * data->priv for cma heap is currently supposed to point
> + * to a "struct device *"
> + */
> + if (data->priv) {
> + cma_heap->dev = data->priv;
> + } else {
> + cma_heap->dev = &cma_heap->default_dma_dev;
That's not good, it's not initialized, or if it is, what's the lifetime
rules for it now?
Why are you needing an extra struct device now?
this seems odd.
greg k-h
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