Re: [PATCH v7 1/6] riscv: mm: dma-noncoherent: Switch using function pointers for cache management

[Christoph Hellwig]

On Thu, Mar 30, 2023 at 09:42:12PM +0100, Prabhakar wrote:
> From: Lad Prabhakar <prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx>
> 
> Currently, selecting which CMOs to use on a given platform is done using
> and ALTERNATIVE_X() macro. This was manageable when there were just two
> CMO implementations, but now that there are more and more platforms coming
> needing custom CMOs, the use of the ALTERNATIVE_X() macro is unmanageable.
> 
> To avoid such issues this patch switches to use of function pointers
> instead of ALTERNATIVE_X() macro for cache management (the only drawback
> being performance over the previous approach).
> 
> void (*clean_range)(unsigned long addr, unsigned long size);
> void (*inv_range)(unsigned long addr, unsigned long size);
> void (*flush_range)(unsigned long addr, unsigned long size);
> 

NAK.  Function pointers for somthing high performance as cache
maintainance is a complete no-go.