Re: [PATCH V5 0/2] Change vring space from nomal memory to dma coherent memory

Greg KH
2020-10-29T01:00:18Z

On Wed, Oct 28, 2020 at 10:03:03AM +0800, Sherry Sun wrote:
> Changes in V5:
> 1. Reorganize the vop_mmap function code in patch 1, which is done by Christoph.
> 2. Completely remove the unnecessary code related to reassign the used ring for
> card in patch 2.
>
> The original vop driver only supports dma coherent device, as it allocates and
> maps vring by _get_free_pages and dma_map_single, but not use
> dma_sync_single_for_cpu/device to sync the updates of device_page/vring between
> EP and RC, which will cause memory synchronization problem for device don't
> support hardware dma coherent.
>
> And allocate vrings use dma_alloc_coherent is a common way in kernel, as the
> memory interacted between two systems should use consistent memory to avoid
> caching effects. So here add noncoherent platform support for vop driver.
> Also add some related dma changes to make sure noncoherent platform works
> well.
>
> Sherry Sun (2):
> misc: vop: change the way of allocating vrings and device page
> misc: vop: do not allocate and reassign the used ring
>
> drivers/misc/mic/bus/vop_bus.h | 2 +
> drivers/misc/mic/host/mic_boot.c | 9 ++
> drivers/misc/mic/host/mic_main.c | 43 ++------
> drivers/misc/mic/vop/vop_debugfs.c | 4 -
> drivers/misc/mic/vop/vop_main.c | 70 +-----------
> drivers/misc/mic/vop/vop_vringh.c | 166 ++++++++++-------------------
> include/uapi/linux/mic_common.h | 9 +-
> 7 files changed, 85 insertions(+), 218 deletions(-)

Have you all seen:
https://lore.kernel.org/r/8c1443136563de34699d2c084df478181c205db4.1603854416.git.sudeep.dutt@intel.com

Looks like this code is asking to just be deleted, is that ok with you?

thanks,

greg k-h