page_vma_mapped_walk() is supposed to check if a page is mapped into a vma.
However, not all page frames (e.g. PFN_DEV) have a associated struct page
with it. There is going to be some duplicate codes similar with this function
if someone want to check if a pfn (without a struct page) is mapped into a
vma. So add support for checking if a pfn is mapped into a vma. In the next
patch, the dax will use this new feature.
Signed-off-by: Muchun Song
---
include/linux/rmap.h| 14 --
include/linux/swapops.h | 13 +++---
mm/internal.h | 28 +---
mm/page_vma_mapped.c| 68 +++--
4 files changed, 83 insertions(+), 40 deletions(-)
diff --git a/include/linux/rmap.h b/include/linux/rmap.h
index 221c3c6438a7..78373935ad49 100644
--- a/include/linux/rmap.h
+++ b/include/linux/rmap.h
@@ -204,9 +204,18 @@ int make_device_exclusive_range(struct mm_struct *mm,
unsigned long start,
#define PVMW_SYNC (1 << 0)
/* Look for migarion entries rather than present PTEs */
#define PVMW_MIGRATION (1 << 1)
+/* Walk the page table by checking the pfn instead of a struct page */
+#define PVMW_PFN_WALK (1 << 2)
struct page_vma_mapped_walk {
- struct page *page;
+ union {
+ struct page *page;
+ struct {
+ unsigned long pfn;
+ unsigned int nr;
+ pgoff_t index;
+ };
+ };
struct vm_area_struct *vma;
unsigned long address;
pmd_t *pmd;
@@ -218,7 +227,8 @@ struct page_vma_mapped_walk {
static inline void page_vma_mapped_walk_done(struct page_vma_mapped_walk *pvmw)
{
/* HugeTLB pte is set to the relevant page table entry without
pte_mapped. */
- if (pvmw->pte && !PageHuge(pvmw->page))
+ if (pvmw->pte && (pvmw->flags & PVMW_PFN_WALK ||
+ !PageHuge(pvmw->page)))
pte_unmap(pvmw->pte);
if (pvmw->ptl)
spin_unlock(pvmw->ptl);
diff --git a/include/linux/swapops.h b/include/linux/swapops.h
index d356ab4047f7..d28bf65fd6a5 100644
--- a/include/linux/swapops.h
+++ b/include/linux/swapops.h
@@ -247,17 +247,22 @@ static inline int is_writable_migration_entry(swp_entry_t
entry)
#endif
-static inline struct page *pfn_swap_entry_to_page(swp_entry_t entry)
+static inline unsigned long pfn_swap_entry_to_pfn(swp_entry_t entry)
{
- struct page *p = pfn_to_page(swp_offset(entry));
+ unsigned long pfn = swp_offset(entry);
/*
* Any use of migration entries may only occur while the
* corresponding page is locked
*/
- BUG_ON(is_migration_entry(entry) && !PageLocked(p));
+ BUG_ON(is_migration_entry(entry) && !PageLocked(pfn_to_page(pfn)));
+
+ return pfn;
+}
- return p;
+static inline struct page *pfn_swap_entry_to_page(swp_entry_t entry)
+{
+ return pfn_to_page(pfn_swap_entry_to_pfn(entry));
}
/*
diff --git a/mm/internal.h b/mm/internal.h
index deb9bda18e59..5458cd08df33 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -478,25 +478,35 @@ vma_address(struct page *page, struct vm_area_struct *vma)
}
/*
- * Then at what user virtual address will none of the page be found in vma?
- * Assumes that vma_address() already returned a good starting address.
- * If page is a compound head, the entire compound page is considered.
+ * Return the end of user virtual address at the specific offset within
+ * a vma.
*/
static inline unsigned long
-vma_address_end(struct page *page, struct vm_area_struct *vma)
+vma_pgoff_address_end(pgoff_t pgoff, unsigned long nr_pages,
+ struct vm_area_struct *vma)
{
- pgoff_t pgoff;
- unsigned long address;
+ unsigned long address = vma->vm_start;
- VM_BUG_ON_PAGE(PageKsm(page), page);/* KSM page->index unusable */
- pgoff = page_to_pgoff(page) + compound_nr(page);
- address = vma->vm_start + ((pgoff - vma->vm_pgoff) << PAGE_SHIFT);
+ address += (pgoff + nr_pages - vma->vm_pgoff) << PAGE_SHIFT;
/* Check for address beyond vma (or wrapped through 0?) */
if (address < vma->vm_start || address > vma->vm_end)
address = vma->vm_end;
return address;
}
+/*
+ * Return the end of user virtual address of a page within a vma. Assumes that
+ * vma_address() already returned a good starting address. If page is a
compound
+ * head, the entire compound page is considered.
+ */
+static inline unsigned long
+vma_address_end(struct page *page, struct vm_area_struct *vma)
+{
+ VM_BUG_ON_PAGE(PageKsm(page), page);/* KSM page->index unusable */
+ return vma_pgoff_address_end(page_to_pgoff(page), compound_nr(page),
+vma);
+}
+
static inline struct file *maybe_unlock_mmap_for_io(struct vm_fault *vmf,
