On Sat, Sep 10, 2022 at 07:30:45AM +0200, Christoph Hellwig wrote: > I think this will work, but unless we have to I'd generally prefer > to just split dta that is DMAed into into a separate allocation. > That is, do a separate kmalloc for the nvme_smart_log structure. Well, both approaches will solve the denoted problem. I am just wondering why do you think that the kmalloc-ed buffer is more preferable? IMO it is a bit less suitable since increases the memory granularity - two kmalloc's instead of one. Moreover it makes the code a bit more complex for the same reason of having two mallocs and two frees. Meanwhile using the ____cacheline_aligned qualifier to prevent the noncoherent DMA problem is a standard approach. What would be the best solution if we had a qualifier like this: #ifdef CONFIG_DMA_NONCOHERENT #define ____dma_buffer ____cacheline_aligned #else #define ____dma_buffer #endif and used it instead of the direct ____cacheline_aligned utilization. -Sergey > > Guenter, is this ok with you?
