On Wed, Nov 24, 2021 at 07:09:59PM +0000, Joao Martins wrote: > Add a new @vmemmap_shift property for struct dev_pagemap which specifies that a > devmap is composed of a set of compound pages of order @vmemmap_shift, instead of > base pages. When a compound page devmap is requested, all but the first > page are initialised as tail pages instead of order-0 pages. Please wrap commit log lines after 73 characters. > #define for_each_device_pfn(pfn, map, i) \ > - for (pfn = pfn_first(map, i); pfn < pfn_end(map, i); pfn = pfn_next(pfn)) > + for (pfn = pfn_first(map, i); pfn < pfn_end(map, i); pfn = pfn_next(map, pfn)) It would be nice to fix up this long line while you're at it. > static void dev_pagemap_kill(struct dev_pagemap *pgmap) > { > @@ -315,8 +315,8 @@ static int pagemap_range(struct dev_pagemap *pgmap, struct mhp_params *params, > memmap_init_zone_device(&NODE_DATA(nid)->node_zones[ZONE_DEVICE], > PHYS_PFN(range->start), > PHYS_PFN(range_len(range)), pgmap); > - percpu_ref_get_many(pgmap->ref, pfn_end(pgmap, range_id) > - - pfn_first(pgmap, range_id)); > + percpu_ref_get_many(pgmap->ref, (pfn_end(pgmap, range_id) > + - pfn_first(pgmap, range_id)) >> pgmap->vmemmap_shift); In the Linux coding style the - goes ointo the first line. But it would be really nice to clean this up with a helper ala pfn_len anyway: percpu_ref_get_many(pgmap->ref, pfn_len(pgmap, range_id) >> pgmap->vmemmap_shift);