[PATCH v4 1/6] mm: add definition of PMD_PAGE_ORDER

Mike Rapoport
2020-08-18T14:16:26Z

From: Mike Rapoport <rppt@linux.ibm.com>

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 <rppt@linux.ibm.com>
---
fs/dax.c | 11 ++++-------
include/linux/pgtable.h | 3 +++
2 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/fs/dax.c b/fs/dax.c
index 95341af1a966..09a7fdb879b6 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;
}

@@ -1455,7 +1452,7 @@ 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;
@@ -1514,7 +1511,7 @@ 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;
@@ -1680,7 +1677,7 @@ 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 a124c21e3204..fb9c386e4f54 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]
*
--
2.26.2