Re: [PATCH net-next 1/7] dma: compile-out DMA sync op calls when not used

[Robin Murphy]

On 31/01/2024 4:52 pm, Simon Horman wrote:
> On Fri, Jan 26, 2024 at 02:54:50PM +0100, Alexander Lobakin wrote:
> > Some platforms do have DMA, but DMA there is always direct and coherent.
> > Currently, even on such platforms DMA sync operations are compiled and
> > called.
> > Add a new hidden Kconfig symbol, DMA_NEED_SYNC, and set it only when
> > either sync operations are needed or there is DMA ops or swiotlb
> > enabled. Set dma_need_sync() and dma_skip_sync() (stub for now)
> > depending on this symbol state and don't call sync ops when
> > dma_skip_sync() is true.
> > The change allows for future optimizations of DMA sync calls depending
> > on compile-time or runtime conditions.
> >
> > Signed-off-by: Alexander Lobakin <aleksander.lobakin@xxxxxxxxx>
>
> Hi Alexander,
>
> This seems to cause x86_64 allmodconfig builds to fail:

Oh yeah, the sync_single_range definitions shouldn't need touching at 
all, since they're unconditional wrappers around regular sync_single 
invocations (which already may or may not do anything).

Thanks,
Robin.

>   ../drivers/media/platform/ti/omap3isp/ispstat.c:82:35: error: ‘dma_sync_single_range_for_device’ undeclared (first use in this function); did you mean ‘dma_sync_sgtable_for_device’?
>      82 |                                   dma_sync_single_range_for_device);
>         |                                   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>         |                                   dma_sync_sgtable_for_device
>   ../drivers/media/platform/ti/omap3isp/ispstat.c:82:35: note: each undeclared identifier is reported only once for each function it appears in
>   ../drivers/media/platform/ti/omap3isp/ispstat.c: In function ‘isp_stat_buf_sync_magic_for_cpu’:
>   ../drivers/media/platform/ti/omap3isp/ispstat.c:94:35: error: ‘dma_sync_single_range_for_cpu’ undeclared (first use in this function); did you mean ‘dma_sync_sgtable_for_cpu’?
>      94 |                                   dma_sync_single_range_for_cpu);
>         |                                   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>         |                                   dma_sync_sgtable_for_cpu