[PATCH] accel/qaic: Support for 0 resize slice execution in BO

[Jeffrey Hugo]

On 10/27/2023 10:43 AM, Jeffrey Hugo wrote:
> From: Pranjal Ramajor Asha Kanojiya <quic_pkanojiy at quicinc.com>
> 
> Add support to partially execute a slice which is resized to zero.
> Executing a zero size slice in a BO should mean that there is no DMA
> transfers involved but you should still configure doorbell and semaphores.
> 
> For example consider a BO of size 18K and it is sliced into 3 6K slices
> and user calls partial execute ioctl with resize as 10K.
> slice 0 - size is 6k and offset is 0, so resize of 10K will not cut short
>            this slice hence we send the entire slice for execution.
> slice 1 - size is 6k and offset is 6k, so resize of 10K will cut short this
>            slice and only the first 4k should be DMA along with configuring
>            doorbell and semaphores.
> slice 2 - size is 6k and offset is 12k, so resize of 10k will cut short
>            this slice and no DMA transfer would be involved but we should
>            would configure doorbell and semaphores.
> 
> This change begs to change the behavior of 0 resize. Currently, 0 resize
> partial execute ioctl behaves exactly like execute ioctl i.e. no resize.
> After this patch all the slice in BO should behave exactly like slice 2 in
> above example.
> 
> Refactor copy_partial_exec_reqs() to make it more readable and less
> complex.
> 
> Signed-off-by: Pranjal Ramajor Asha Kanojiya <quic_pkanojiy at quicinc.com>
> Reviewed-by: Jeffrey Hugo <quic_jhugo at quicinc.com>
> Signed-off-by: Jeffrey Hugo <quic_jhugo at quicinc.com>

Pushed to drm-misc-next

-Jeff