[v7,1/7] mm: add definition of PMD_PAGE_ORDER

Commit Message

Mike Rapoport Oct. 26, 2020, 8:37 a.m. UTC

From: Mike Rapoport <[e-mail]>

The definition of PMD_PAGE_ORDER denoting the number of base pages in the
second-level leaf page is already used by DAX and maybe handy in other
cases as well.

Several architectures already have definition of PMD_ORDER as the size of
second level page table, so to avoid conflict with these definitions use
PMD_PAGE_ORDER name and update DAX respectively.

Signed-off-by: Mike Rapoport <[e-mail]>
---
 fs/dax.c                | 11 ++++-------
 include/linux/pgtable.h |  3 +++
 2 files changed, 7 insertions(+), 7 deletions(-)

Comments

David Hildenbrand Oct. 27, 2020, 8:26 a.m. UTC | #1

On 26.10.20 09:37, Mike Rapoport wrote:
> From: Mike Rapoport <[e-mail]>
> 
> The definition of PMD_PAGE_ORDER denoting the number of base pages in the
> second-level leaf page is already used by DAX and maybe handy in other
> cases as well.
> 
> Several architectures already have definition of PMD_ORDER as the size of
> second level page table, so to avoid conflict with these definitions use
> PMD_PAGE_ORDER name and update DAX respectively.
> 
> Signed-off-by: Mike Rapoport <[e-mail]>

Reviewed-by: David Hildenbrand <[e-mail]>

Patch

diff --git a/fs/dax.c b/fs/dax.c
index 5b47834f2e1b..de3dbcaa849a 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -49,9 +49,6 @@  static inline unsigned int pe_order(enum page_entry_size pe_size)
 #define PG_PMD_COLOUR	((PMD_SIZE >> PAGE_SHIFT) - 1)
 #define PG_PMD_NR	(PMD_SIZE >> PAGE_SHIFT)
 
-/* The order of a PMD entry */
-#define PMD_ORDER	(PMD_SHIFT - PAGE_SHIFT)
-
 static wait_queue_head_t wait_table[DAX_WAIT_TABLE_ENTRIES];
 
 static int __init init_dax_wait_table(void)
@@ -98,7 +95,7 @@  static bool dax_is_locked(void *entry)
 static unsigned int dax_entry_order(void *entry)
 {
 	if (xa_to_value(entry) & DAX_PMD)
-		return PMD_ORDER;
+		return PMD_PAGE_ORDER;
 	return 0;
 }
 
@@ -1471,7 +1468,7 @@  static vm_fault_t dax_iomap_pmd_fault(struct vm_fault *vmf, pfn_t *pfnp,
 {
 	struct vm_area_struct *vma = vmf->vma;
 	struct address_space *mapping = vma->vm_file->f_mapping;
-	XA_STATE_ORDER(xas, &mapping->i_pages, vmf->pgoff, PMD_ORDER);
+	XA_STATE_ORDER(xas, &mapping->i_pages, vmf->pgoff, PMD_PAGE_ORDER);
 	unsigned long pmd_addr = vmf->address & PMD_MASK;
 	bool write = vmf->flags & FAULT_FLAG_WRITE;
 	bool sync;
@@ -1530,7 +1527,7 @@  static vm_fault_t dax_iomap_pmd_fault(struct vm_fault *vmf, pfn_t *pfnp,
 	 * entry is already in the array, for instance), it will return
 	 * VM_FAULT_FALLBACK.
 	 */
-	entry = grab_mapping_entry(&xas, mapping, PMD_ORDER);
+	entry = grab_mapping_entry(&xas, mapping, PMD_PAGE_ORDER);
 	if (xa_is_internal(entry)) {
 		result = xa_to_internal(entry);
 		goto fallback;
@@ -1696,7 +1693,7 @@  dax_insert_pfn_mkwrite(struct vm_fault *vmf, pfn_t pfn, unsigned int order)
 	if (order == 0)
 		ret = vmf_insert_mixed_mkwrite(vmf->vma, vmf->address, pfn);
 #ifdef CONFIG_FS_DAX_PMD
-	else if (order == PMD_ORDER)
+	else if (order == PMD_PAGE_ORDER)
 		ret = vmf_insert_pfn_pmd(vmf, pfn, FAULT_FLAG_WRITE);
 #endif
 	else
diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
index 38c33eabea89..bd0617fe066e 100644
--- a/include/linux/pgtable.h
+++ b/include/linux/pgtable.h
@@ -28,6 +28,9 @@ 
 #define USER_PGTABLES_CEILING	0UL
 #endif
 
+/* Number of base pages in a second level leaf page */
+#define PMD_PAGE_ORDER	(PMD_SHIFT - PAGE_SHIFT)
+
 /*
  * A page table page can be thought of an array like this: pXd_t[PTRS_PER_PxD]
  *