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

From: Simon Horman <[email-masked]>
Date: Wed, 31 Jan 2024 17:52:58 +0100

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 <[email-masked]>

Hi Alexander,

This seems to cause x86_64 allmodconfig builds to fail:

 ../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