Re: [RFC PATCH 0/2] Add UIO device supporting dynamic memory allocation

["Hans J. Koch" <hjk@hansjkoch.de>]

On Wed, Sep 12, 2012 at 02:29:43PM +0900, Damian Hobson-Garcia wrote:
> Reposting: I realized that this series should have gone out to a broader list.

You forgot GregKH, I added him.

> My apologies to those who those who will recieve a duplicate post. 
> 
> Hello all,
> 
> I've been using this UIO driver for allocation/deallocation
> of memory regions through an IOMMU via the dma-mapping API, but
> it seems that it would be more generally useful for userspace drivers
> to access CMA memory regions. I don't know if it's useful to try to add
> this functionality into the core uio driver or not, so for now I've kept
> all dynamic memory handling in the specific device driver.
> 
> The number and size of the dynamically allocatable regions is defined
> statically in the device platform data, and the actually memory is
> allocated and deallocated when the device is opened/closed.
> 
> Details of the dynamically allocated regions are available from sysfs in
> exactly the same was as for static regions. The total number of
> dynamic and static regions combined cannot exceed MAX_UIO_MAPS.
> 
> Any comments, especially with regard to exposing the dma-mapping API to
> userspace in this way, would be greatly appreciated.
> 
> Damian Hobson-Garcia (2):
>   Add new uio device for dynamic memory allocation
>   ARM: shmobile: sh7372: Change VPU UIO to uio_dmem_genirq
> 
>  arch/arm/mach-shmobile/setup-sh7372.c         |   19 +-
>  drivers/uio/Kconfig                           |   16 ++
>  drivers/uio/Makefile                          |    1 +
>  drivers/uio/uio_dmem_genirq.c                 |  356 +++++++++++++++++++++++++
>  include/linux/platform_data/uio_dmem_genirq.h |   26 ++
>  5 files changed, 413 insertions(+), 5 deletions(-)
>  create mode 100644 drivers/uio/uio_dmem_genirq.c
>  create mode 100644 include/linux/platform_data/uio_dmem_genirq.h

Please add a third patch with a few words for Documentation/DocBook/uio-howto.tmpl
since this driver could be useful for other people, too.

Otherwise, looks good to me.

Thanks,
Hans