Hi Dan, While testing device mapper with DAX, I faced a bug with the commit: commit ad428cdb525a97d15c0349fdc80f3d58befb50df Author: Dan Williams <dan.j.williams@xxxxxxxxx> Date: Wed Feb 20 21:12:50 2019 -0800 When I reverted the condition to old code[1] it worked for me. I am thinking when we map two different devices (e.g with device mapper), will start & end pfn still point to same pgmap? Or there is something else which I am missing here. Note: I tested only EXT4. [1] - if (pgmap && pgmap->type == MEMORY_DEVICE_FS_DAX) + end_pgmap = get_dev_pagemap(pfn_t_to_pfn(end_pfn), NULL); + if (pgmap && pgmap == end_pgmap && pgmap->type == MEMORY_DEVICE_FS_DAX + && pfn_t_to_page(pfn)->pgmap == pgmap + && pfn_t_to_page(end_pfn)->pgmap == pgmap + && pfn_t_to_pfn(pfn) == PHYS_PFN(__pa(kaddr)) + && pfn_t_to_pfn(end_pfn) == PHYS_PFN(__pa(end_kaddr))) dax_enabled = true; put_dev_pagemap(pgmap); Thanks, Pankaj _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/virtualization