12 Mar
2020
12 Mar
'20
10:19 a.m.
On Thu, Mar 12, 2020 at 11:14:22AM +0100, Christian König wrote:
The page pointer is set to NULL and only the DMA address, length and offset values are valid.
NAK. The only valid way to fill DMA address in scatterlists is dma_map_sg / dma_map_sg_attr.
How can we then map PCIe BARs into an scatterlist which are not backed by struct pages?
You can't. scatterlists by definition map memory backed by a struct page. If you want to map something else struct scatterlist is the wrong structure and you need to use something else (which you should anyway as struct scatterlist is a bad design patter, and the above is only one of the many issues with it).