On Tue, Dec 19, 2023 at 11:25:14AM +0530, Nilesh Javali wrote: > The dma_alloc_coherent no more provide __GFP_COMP allocation as per commit, > dma-mapping: reject __GFP_COMP in dma_alloc_attrs, and hence > instead use __get_free_pages for __GFP_COMP allocation along with > dma_map_single to get dma address in order to fix page reference counting > issue caused in iscsiuio mmap. You can't just do a single map for things mapped to userspace, as that breaks setups that are not DMA coherent. There was a patch floating around to explicitly support dma coherent allocations in uio, which is the right thing to do.
