The patch titled
Subject: mm/pgmap: use correct alignment when looking at first pfn from a region
has been added to the -mm tree. Its filename is
mm-pgmap-use-correct-alignment-when-looking-at-first-pfn-from-a-region.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-pgmap-use-correct-alignment-when-looking-at-first-pfn-from-a-region.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-pgmap-use-correct-alignment-when-looking-at-first-pfn-from-a-region.patch
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------------------------------------------------------
From: "Aneesh Kumar K.V" <aneesh.kumar@xxxxxxxxxxxxx>
Subject: mm/pgmap: use correct alignment when looking at first pfn from a region
vmem_altmap_offset() adjusts 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);
This was found by code inspection. If the pmem region is not correctly
section aligned we can skip pfns while iterating device pfn using
for_each_device_pfn(pfn, pgmap)
Link: http://lkml.kernel.org/r/20190917153129.12905-1-aneesh.kumar@xxxxxxxxxxxxx
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxx>
Cc: Ralph Campbell <rcampbell@xxxxxxxxxx>
Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memremap.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)
--- a/mm/memremap.c~mm-pgmap-use-correct-alignment-when-looking-at-first-pfn-from-a-region
+++ a/mm/memremap.c
@@ -55,8 +55,16 @@ static void pgmap_array_delete(struct re
static unsigned long pfn_first(struct dev_pagemap *pgmap)
{
- return PHYS_PFN(pgmap->res.start) +
- vmem_altmap_offset(pgmap_altmap(pgmap));
+ const struct resource *res = &pgmap->res;
+ struct vmem_altmap *altmap = pgmap_altmap(pgmap);
+ unsigned long pfn;
+
+ if (altmap) {
+ pfn = altmap->base_pfn + vmem_altmap_offset(altmap);
+ } else
+ pfn = PHYS_PFN(res->start);
+
+ return pfn;
}
static unsigned long pfn_end(struct dev_pagemap *pgmap)
_
Patches currently in -mm which might be from aneesh.kumar@xxxxxxxxxxxxx are
mm-pgmap-use-correct-alignment-when-looking-at-first-pfn-from-a-region.patch
