Commit 05ea8860 authored by Dan Williams's avatar Dan Williams Committed by Linus Torvalds

mm, hugetlbfs: introduce ->pagesize() to vm_operations_struct

When device-dax is operating in huge-page mode we want it to behave like
hugetlbfs and report the MMU page mapping size that is being enforced by
the vma.

Similar to commit 31383c68 "mm, hugetlbfs: introduce ->split() to
vm_operations_struct" it would be messy to teach vma_mmu_pagesize()
about device-dax page mapping sizes in the same (hstate) way that
hugetlbfs communicates this attribute.  Instead, these patches introduce
a new ->pagesize() vm operation.

Link: default avatarDan Williams <>
Reported-by: default avatarJane Chu <>
Reviewed-by: default avatarAndrew Morton <>
Cc: Benjamin Herrenschmidt <>
Cc: Michael Ellerman <>
Cc: Paul Mackerras <>
Signed-off-by: default avatarAndrew Morton <>
Signed-off-by: default avatarLinus Torvalds <>
parent 09135cc5
......@@ -390,6 +390,7 @@ struct vm_operations_struct {
int (*huge_fault)(struct vm_fault *vmf, enum page_entry_size pe_size);
void (*map_pages)(struct vm_fault *vmf,
pgoff_t start_pgoff, pgoff_t end_pgoff);
unsigned long (*pagesize)(struct vm_area_struct * area);
/* notification that a previously read-only page is about to become
* writable, if an error is returned it will cause a SIGBUS */
......@@ -637,14 +637,9 @@ EXPORT_SYMBOL_GPL(linear_hugepage_index);
unsigned long vma_kernel_pagesize(struct vm_area_struct *vma)
struct hstate *hstate;
if (!is_vm_hugetlb_page(vma))
return PAGE_SIZE;
hstate = hstate_vma(vma);
return 1UL << huge_page_shift(hstate);
if (vma->vm_ops && vma->vm_ops->pagesize)
return vma->vm_ops->pagesize(vma);
return PAGE_SIZE;
......@@ -3151,6 +3146,13 @@ static int hugetlb_vm_op_split(struct vm_area_struct *vma, unsigned long addr)
return 0;
static unsigned long hugetlb_vm_op_pagesize(struct vm_area_struct *vma)
struct hstate *hstate = hstate_vma(vma);
return 1UL << huge_page_shift(hstate);
* We cannot handle pagefaults against hugetlb pages at all. They cause
* handle_mm_fault() to try to instantiate regular-sized pages in the
......@@ -3168,6 +3170,7 @@ const struct vm_operations_struct hugetlb_vm_ops = {
.open = hugetlb_vm_op_open,
.close = hugetlb_vm_op_close,
.split = hugetlb_vm_op_split,
.pagesize = hugetlb_vm_op_pagesize,
static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page,
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