We already add the start_pad to the resource->start but fails to section
align the start. This make sure with altmap we compute the right first
pfn when start_pad is zero and we are doing an align down of start address.
vmem_altmap_offset() adjust the section aligned base_pfn offset.
So we need to make sure we account for the same when computing base_pfn.
ie, for altmap_valid case, our pfn_first should be:
pfn_first = altmap->base_pfn + vmem_altmap_offset(altmap);
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxx>
---
kernel/memremap.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/kernel/memremap.c b/kernel/memremap.c
index 1490e63f69a9..bf488b8658e7 100644
--- a/kernel/memremap.c
+++ b/kernel/memremap.c
@@ -60,9 +60,11 @@ static unsigned long pfn_first(struct dev_pagemap *pgmap)
struct vmem_altmap *altmap = &pgmap->altmap;
unsigned long pfn;
- pfn = res->start >> PAGE_SHIFT;
- if (pgmap->altmap_valid)
- pfn += vmem_altmap_offset(altmap);
+ if (pgmap->altmap_valid) {
+ pfn = altmap->base_pfn + vmem_altmap_offset(altmap);
+ } else
+ pfn = PHYS_PFN(res->start);
+
return pfn;
}
--
2.21.0
