Several functions in gup.c assume that a compound page has virtually
contiguous page structs. This isn't true for SPARSEMEM configs unless
SPARSEMEM_VMEMMAP is also set. Fix them by using nth_page() instead of
plain pointer arithmetic.
Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
---
mm/gup.c | 14 +++++++-------
1 file changed, 7 insertions(+), 7 deletions(-)
diff --git a/mm/gup.c b/mm/gup.c
index 8a0ea220ced1..9c0a702a4e03 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -235,7 +235,7 @@ static inline struct page *compound_range_next(unsigned long i,
struct page *next, *page;
unsigned int nr = 1;
- next = start + i;
+ next = nth_page(start, i);
page = compound_head(next);
if (PageHead(page))
nr = min_t(unsigned int,
@@ -2430,8 +2430,8 @@ static int record_subpages(struct page *page, unsigned long addr,
{
int nr;
- for (nr = 0; addr != end; addr += PAGE_SIZE)
- pages[nr++] = page++;
+ for (nr = 0; addr != end; nr++, addr += PAGE_SIZE)
+ pages[nr] = nth_page(page, nr);
return nr;
}
@@ -2466,7 +2466,7 @@ static int gup_hugepte(pte_t *ptep, unsigned long sz, unsigned long addr,
VM_BUG_ON(!pfn_valid(pte_pfn(pte)));
head = pte_page(pte);
- page = head + ((addr & (sz-1)) >> PAGE_SHIFT);
+ page = nth_page(head, (addr & (sz-1)) >> PAGE_SHIFT);
refs = record_subpages(page, addr, end, pages + *nr);
head = try_grab_compound_head(head, refs, flags);
@@ -2526,7 +2526,7 @@ static int gup_huge_pmd(pmd_t orig, pmd_t *pmdp, unsigned long addr,
pages, nr);
}
- page = pmd_page(orig) + ((addr & ~PMD_MASK) >> PAGE_SHIFT);
+ page = nth_page(pmd_page(orig), (addr & ~PMD_MASK) >> PAGE_SHIFT);
refs = record_subpages(page, addr, end, pages + *nr);
head = try_grab_compound_head(pmd_page(orig), refs, flags);
@@ -2560,7 +2560,7 @@ static int gup_huge_pud(pud_t orig, pud_t *pudp, unsigned long addr,
pages, nr);
}
- page = pud_page(orig) + ((addr & ~PUD_MASK) >> PAGE_SHIFT);
+ page = nth_page(pud_page(orig), (addr & ~PUD_MASK) >> PAGE_SHIFT);
refs = record_subpages(page, addr, end, pages + *nr);
head = try_grab_compound_head(pud_page(orig), refs, flags);
@@ -2589,7 +2589,7 @@ static int gup_huge_pgd(pgd_t orig, pgd_t *pgdp, unsigned long addr,
BUILD_BUG_ON(pgd_devmap(orig));
- page = pgd_page(orig) + ((addr & ~PGDIR_MASK) >> PAGE_SHIFT);
+ page = nth_page(pgd_page(orig), (addr & ~PGDIR_MASK) >> PAGE_SHIFT);
refs = record_subpages(page, addr, end, pages + *nr);
head = try_grab_compound_head(pgd_page(orig), refs, flags);
--
2.33.0
