From: Dan Williams <dan.j.williams@intel.com>
Date: Thu, 5 Apr 2018 16:24:25 -0700
Subject: mm, hugetlbfs: introduce ->pagesize() to vm_operations_struct
Git-commit: 05ea88608d4e135695571727f5d7f22967d2a3bf
Patch-mainline: v4.17-rc1
References: FATE#324506
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 31383c6865a5 "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: http://lkml.kernel.org/r/151996254734.27922.15813097401404359642.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Reported-by: Jane Chu <jane.chu@oracle.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Acked-by: Johannes Thumshirn <jthumshirn@suse.de>
---
include/linux/mm.h | 1 +
mm/hugetlb.c | 19 +++++++++++--------
2 files changed, 12 insertions(+), 8 deletions(-)
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 2e2be527642a..7c06581edaa2 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -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 */
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 92c49b9d7cbb..218679138255 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -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;
}
EXPORT_SYMBOL_GPL(vma_kernel_pagesize);
@@ -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,