On Wed, 2020-06-03 at 18:16 +0200, David Hildenbrand wrote: > On 03.06.20 18:11, Miles Chen wrote: > > max_pfn is uesd to get the highest pfn in the system. Drivers like > > drivers/iommu/mtk_iommu.c checks max_pfn to see if it should enable > > its "4GB mode". > > > > This patch exports the max_pfn symbol, so we can build the driver as > > a kernel module. > > Please add that change to the respective user patch (and cc MM-people > for that patch), so we have the actual user right along the change and > can figure out if this is the right thing to do. > Thanks for the comment. Mike points out another alternative way to do this by totalram_pages(). I will use that approach so we don't have to export max_pfn here. https://lkml.org/lkml/2020/6/3/771 Miles > > > > Signed-off-by: Miles Chen <miles.chen@xxxxxxxxxxxx> > > --- > > mm/memblock.c | 1 + > > 1 file changed, 1 insertion(+) > > > > diff --git a/mm/memblock.c b/mm/memblock.c > > index c79ba6f9920c..3b2b21ecebb6 100644 > > --- a/mm/memblock.c > > +++ b/mm/memblock.c > > @@ -99,6 +99,7 @@ EXPORT_SYMBOL(contig_page_data); > > unsigned long max_low_pfn; > > unsigned long min_low_pfn; > > unsigned long max_pfn; > > +EXPORT_SYMBOL(max_pfn); > > unsigned long long max_possible_pfn; > > > > static struct memblock_region memblock_memory_init_regions[INIT_MEMBLOCK_REGIONS] __initdata_memblock; > > > >
