dax: use folios more widely within DAX

Convert from pfn to folio instead of page and use those folios throughout
to avoid accesses to page->index and page->mapping.

Link: https://lkml.kernel.org/r/20241216155408.8102-2-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Jane Chu <jane.chu@oracle.com>
Cc: Dan Willaims <dan.j.williams@intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: Alistair Popple <apopple@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/fs/dax.c b/fs/dax.c
index 21b47402b3dca4684f5caff34d68cfd0df993080..972febc6fb9d448e97d34084ccbdcae1ae05bd5c 100644 (file)
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -320,38 +320,39 @@ static unsigned long dax_end_pfn(void *entry)
        for (pfn = dax_to_pfn(entry); \
                        pfn < dax_end_pfn(entry); pfn++)
 
-static inline bool dax_page_is_shared(struct page *page)
+static inline bool dax_folio_is_shared(struct folio *folio)
 {
-       return page->mapping == PAGE_MAPPING_DAX_SHARED;
+       return folio->mapping == PAGE_MAPPING_DAX_SHARED;
 }
 
 /*
- * Set the page->mapping with PAGE_MAPPING_DAX_SHARED flag, increase the
+ * Set the folio->mapping with PAGE_MAPPING_DAX_SHARED flag, increase the
  * refcount.
  */
-static inline void dax_page_share_get(struct page *page)
+static inline void dax_folio_share_get(struct folio *folio)
 {
-       if (page->mapping != PAGE_MAPPING_DAX_SHARED) {
+       if (folio->mapping != PAGE_MAPPING_DAX_SHARED) {
                /*
                 * Reset the index if the page was already mapped
                 * regularly before.
                 */
-               if (page->mapping)
-                       page->share = 1;
-               page->mapping = PAGE_MAPPING_DAX_SHARED;
+               if (folio->mapping)
+                       folio->page.share = 1;
+               folio->mapping = PAGE_MAPPING_DAX_SHARED;
        }
-       page->share++;
+       folio->page.share++;
 }
 
-static inline unsigned long dax_page_share_put(struct page *page)
+static inline unsigned long dax_folio_share_put(struct folio *folio)
 {
-       return --page->share;
+       return --folio->page.share;
 }
 
 /*
- * When it is called in dax_insert_entry(), the shared flag will indicate that
- * whether this entry is shared by multiple files.  If so, set the page->mapping
- * PAGE_MAPPING_DAX_SHARED, and use page->share as refcount.
+ * When it is called in dax_insert_entry(), the shared flag will indicate
+ * that whether this entry is shared by multiple files.  If so, set
+ * the folio->mapping PAGE_MAPPING_DAX_SHARED, and use page->share
+ * as refcount.
  */
 static void dax_associate_entry(void *entry, struct address_space *mapping,
                struct vm_area_struct *vma, unsigned long address, bool shared)
@@ -364,14 +365,14 @@ static void dax_associate_entry(void *entry, struct address_space *mapping,
 
        index = linear_page_index(vma, address & ~(size - 1));
        for_each_mapped_pfn(entry, pfn) {
-               struct page *page = pfn_to_page(pfn);
+               struct folio *folio = pfn_folio(pfn);
 
                if (shared) {
-                       dax_page_share_get(page);
+                       dax_folio_share_get(folio);
                } else {
-                       WARN_ON_ONCE(page->mapping);
-                       page->mapping = mapping;
-                       page->index = index + i++;
+                       WARN_ON_ONCE(folio->mapping);
+                       folio->mapping = mapping;
+                       folio->index = index + i++;
                }
        }
 }
@@ -385,17 +386,17 @@ static void dax_disassociate_entry(void *entry, struct address_space *mapping,
                return;
 
        for_each_mapped_pfn(entry, pfn) {
-               struct page *page = pfn_to_page(pfn);
+               struct folio *folio = pfn_folio(pfn);
 
-               WARN_ON_ONCE(trunc && page_ref_count(page) > 1);
-               if (dax_page_is_shared(page)) {
+               WARN_ON_ONCE(trunc && folio_ref_count(folio) > 1);
+               if (dax_folio_is_shared(folio)) {
                        /* keep the shared flag if this page is still shared */
-                       if (dax_page_share_put(page) > 0)
+                       if (dax_folio_share_put(folio) > 0)
                                continue;
                } else
-                       WARN_ON_ONCE(page->mapping && page->mapping != mapping);
-               page->mapping = NULL;
-               page->index = 0;
+                       WARN_ON_ONCE(folio->mapping && folio->mapping != mapping);
+               folio->mapping = NULL;
+               folio->index = 0;
        }
 }