1 files changed, 114 insertions, 72 deletions

diff --git a/fs/dax.c b/fs/dax.c
index 6674540363e8..cf96f3dd4e5f 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -71,6 +71,11 @@ static unsigned long dax_to_pfn(void *entry)
 	return xa_to_value(entry) >> DAX_SHIFT;
 }
 
+static struct folio *dax_to_folio(void *entry)
+{
+	return page_folio(pfn_to_page(dax_to_pfn(entry)));
+}
+
 static void *dax_make_entry(pfn_t pfn, unsigned long flags)
 {
 	return xa_mk_value(flags | (pfn_t_to_pfn(pfn) << DAX_SHIFT));
@@ -338,19 +343,6 @@ static unsigned long dax_entry_size(void *entry)
 		return PAGE_SIZE;
 }
 
-static unsigned long dax_end_pfn(void *entry)
-{
-	return dax_to_pfn(entry) + dax_entry_size(entry) / PAGE_SIZE;
-}
-
-/*
- * Iterate through all mapped pfns represented by an entry, i.e. skip
- * 'empty' and 'zero' entries.
- */
-#define for_each_mapped_pfn(entry, pfn) \
-	for (pfn = dax_to_pfn(entry); \
-			pfn < dax_end_pfn(entry); pfn++)
-
 /*
  * A DAX folio is considered shared if it has no mapping set and ->share (which
  * shares the ->index field) is non-zero. Note this may return false even if the
@@ -359,7 +351,7 @@ static unsigned long dax_end_pfn(void *entry)
  */
 static inline bool dax_folio_is_shared(struct folio *folio)
 {
-	return !folio->mapping && folio->page.share;
+	return !folio->mapping && folio->share;
 }
 
 /*
@@ -384,75 +376,117 @@ static void dax_folio_make_shared(struct folio *folio)
 	 * folio has previously been mapped into one address space so set the
 	 * share count.
 	 */
-	folio->page.share = 1;
+	folio->share = 1;
 }
 
-static inline unsigned long dax_folio_share_put(struct folio *folio)
+static inline unsigned long dax_folio_put(struct folio *folio)
 {
-	return --folio->page.share;
+	unsigned long ref;
+	int order, i;
+
+	if (!dax_folio_is_shared(folio))
+		ref = 0;
+	else
+		ref = --folio->share;
+
+	if (ref)
+		return ref;
+
+	folio->mapping = NULL;
+	order = folio_order(folio);
+	if (!order)
+		return 0;
+
+	for (i = 0; i < (1UL << order); i++) {
+		struct dev_pagemap *pgmap = page_pgmap(&folio->page);
+		struct page *page = folio_page(folio, i);
+		struct folio *new_folio = (struct folio *)page;
+
+		ClearPageHead(page);
+		clear_compound_head(page);
+
+		new_folio->mapping = NULL;
+		/*
+		 * Reset pgmap which was over-written by
+		 * prep_compound_page().
+		 */
+		new_folio->pgmap = pgmap;
+		new_folio->share = 0;
+		WARN_ON_ONCE(folio_ref_count(new_folio));
+	}
+
+	return ref;
+}
+
+static void dax_folio_init(void *entry)
+{
+	struct folio *folio = dax_to_folio(entry);
+	int order = dax_entry_order(entry);
+
+	/*
+	 * Folio should have been split back to order-0 pages in
+	 * dax_folio_put() when they were removed from their
+	 * final mapping.
+	 */
+	WARN_ON_ONCE(folio_order(folio));
+
+	if (order > 0) {
+		prep_compound_page(&folio->page, order);
+		if (order > 1)
+			INIT_LIST_HEAD(&folio->_deferred_list);
+		WARN_ON_ONCE(folio_ref_count(folio));
+	}
 }
 
 static void dax_associate_entry(void *entry, struct address_space *mapping,
-		struct vm_area_struct *vma, unsigned long address, bool shared)
+				struct vm_area_struct *vma,
+				unsigned long address, bool shared)
 {
-	unsigned long size = dax_entry_size(entry), pfn, index;
-	int i = 0;
+	unsigned long size = dax_entry_size(entry), index;
+	struct folio *folio = dax_to_folio(entry);
 
 	if (IS_ENABLED(CONFIG_FS_DAX_LIMITED))
 		return;
 
 	index = linear_page_index(vma, address & ~(size - 1));
-	for_each_mapped_pfn(entry, pfn) {
-		struct folio *folio = pfn_folio(pfn);
-
-		if (shared && (folio->mapping || folio->page.share)) {
-			if (folio->mapping)
-				dax_folio_make_shared(folio);
+	if (shared && (folio->mapping || dax_folio_is_shared(folio))) {
+		if (folio->mapping)
+			dax_folio_make_shared(folio);
 
-			WARN_ON_ONCE(!folio->page.share);
-			folio->page.share++;
-		} else {
-			WARN_ON_ONCE(folio->mapping);
-			folio->mapping = mapping;
-			folio->index = index + i++;
-		}
+		WARN_ON_ONCE(!folio->share);
+		WARN_ON_ONCE(dax_entry_order(entry) != folio_order(folio));
+		folio->share++;
+	} else {
+		WARN_ON_ONCE(folio->mapping);
+		dax_folio_init(entry);
+		folio = dax_to_folio(entry);
+		folio->mapping = mapping;
+		folio->index = index;
 	}
 }
 
 static void dax_disassociate_entry(void *entry, struct address_space *mapping,
-		bool trunc)
+				bool trunc)
 {
-	unsigned long pfn;
+	struct folio *folio = dax_to_folio(entry);
 
 	if (IS_ENABLED(CONFIG_FS_DAX_LIMITED))
 		return;
 
-	for_each_mapped_pfn(entry, pfn) {
-		struct folio *folio = pfn_folio(pfn);
-
-		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_folio_share_put(folio) > 0)
-				continue;
-		} else
-			WARN_ON_ONCE(folio->mapping && folio->mapping != mapping);
-		folio->mapping = NULL;
-		folio->index = 0;
-	}
+	dax_folio_put(folio);
 }
 
 static struct page *dax_busy_page(void *entry)
 {
-	unsigned long pfn;
+	struct folio *folio = dax_to_folio(entry);
 
-	for_each_mapped_pfn(entry, pfn) {
-		struct page *page = pfn_to_page(pfn);
+	if (dax_is_zero_entry(entry) || dax_is_empty_entry(entry))
+		return NULL;
 
-		if (page_ref_count(page) > 1)
-			return page;
-	}
-	return NULL;
+	if (folio_ref_count(folio) - folio_mapcount(folio))
+		return &folio->page;
+	else
+		return NULL;
 }
 
 /**
@@ -785,7 +819,7 @@ struct page *dax_layout_busy_page(struct address_space *mapping)
 EXPORT_SYMBOL_GPL(dax_layout_busy_page);
 
 static int __dax_invalidate_entry(struct address_space *mapping,
-					  pgoff_t index, bool trunc)
+				  pgoff_t index, bool trunc)
 {
 	XA_STATE(xas, &mapping->i_pages, index);
 	int ret = 0;
@@ -953,7 +987,8 @@ void dax_break_layout_final(struct inode *inode)
 		wait_page_idle_uninterruptible(page, inode);
 	} while (true);
 
-	dax_delete_mapping_range(inode->i_mapping, 0, LLONG_MAX);
+	if (!page)
+		dax_delete_mapping_range(inode->i_mapping, 0, LLONG_MAX);
 }
 EXPORT_SYMBOL_GPL(dax_break_layout_final);
 
@@ -1039,8 +1074,10 @@ static void *dax_insert_entry(struct xa_state *xas, struct vm_fault *vmf,
 		void *old;
 
 		dax_disassociate_entry(entry, mapping, false);
-		dax_associate_entry(new_entry, mapping, vmf->vma, vmf->address,
-				shared);
+		if (!(flags & DAX_ZERO_PAGE))
+			dax_associate_entry(new_entry, mapping, vmf->vma,
+					vmf->address, shared);
+
 		/*
 		 * Only swap our new entry into the page cache if the current
 		 * entry is a zero page or an empty entry.  If a normal PTE or
@@ -1228,9 +1265,7 @@ static int dax_iomap_direct_access(const struct iomap *iomap, loff_t pos,
 		goto out;
 	if (pfn_t_to_pfn(*pfnp) & (PHYS_PFN(size)-1))
 		goto out;
-	/* For larger pages we need devmap */
-	if (length > 1 && !pfn_t_devmap(*pfnp))
-		goto out;
+
 	rc = 0;
 
 out_check_addr:
@@ -1337,7 +1372,7 @@ static vm_fault_t dax_load_hole(struct xa_state *xas, struct vm_fault *vmf,
 
 	*entry = dax_insert_entry(xas, vmf, iter, *entry, pfn, DAX_ZERO_PAGE);
 
-	ret = vmf_insert_mixed(vmf->vma, vaddr, pfn);
+	ret = vmf_insert_page_mkwrite(vmf, pfn_t_to_page(pfn), false);
 	trace_dax_load_hole(inode, vmf, ret);
 	return ret;
 }
@@ -1808,7 +1843,8 @@ static vm_fault_t dax_fault_iter(struct vm_fault *vmf,
 	loff_t pos = (loff_t)xas->xa_index << PAGE_SHIFT;
 	bool write = iter->flags & IOMAP_WRITE;
 	unsigned long entry_flags = pmd ? DAX_PMD : 0;
-	int err = 0;
+	struct folio *folio;
+	int ret, err = 0;
 	pfn_t pfn;
 	void *kaddr;
 
@@ -1840,17 +1876,19 @@ static vm_fault_t dax_fault_iter(struct vm_fault *vmf,
 			return dax_fault_return(err);
 	}
 
+	folio = dax_to_folio(*entry);
 	if (dax_fault_is_synchronous(iter, vmf->vma))
 		return dax_fault_synchronous_pfnp(pfnp, pfn);
 
-	/* insert PMD pfn */
+	folio_ref_inc(folio);
 	if (pmd)
-		return vmf_insert_pfn_pmd(vmf, pfn, write);
+		ret = vmf_insert_folio_pmd(vmf, pfn_folio(pfn_t_to_pfn(pfn)),
+					write);
+	else
+		ret = vmf_insert_page_mkwrite(vmf, pfn_t_to_page(pfn), write);
+	folio_put(folio);
 
-	/* insert PTE pfn */
-	if (write)
-		return vmf_insert_mixed_mkwrite(vmf->vma, vmf->address, pfn);
-	return vmf_insert_mixed(vmf->vma, vmf->address, pfn);
+	return ret;
 }
 
 static vm_fault_t dax_iomap_pte_fault(struct vm_fault *vmf, pfn_t *pfnp,
@@ -2089,6 +2127,7 @@ dax_insert_pfn_mkwrite(struct vm_fault *vmf, pfn_t pfn, unsigned int order)
 {
 	struct address_space *mapping = vmf->vma->vm_file->f_mapping;
 	XA_STATE_ORDER(xas, &mapping->i_pages, vmf->pgoff, order);
+	struct folio *folio;
 	void *entry;
 	vm_fault_t ret;
 
@@ -2106,14 +2145,17 @@ dax_insert_pfn_mkwrite(struct vm_fault *vmf, pfn_t pfn, unsigned int order)
 	xas_set_mark(&xas, PAGECACHE_TAG_DIRTY);
 	dax_lock_entry(&xas, entry);
 	xas_unlock_irq(&xas);
+	folio = pfn_folio(pfn_t_to_pfn(pfn));
+	folio_ref_inc(folio);
 	if (order == 0)
-		ret = vmf_insert_mixed_mkwrite(vmf->vma, vmf->address, pfn);
+		ret = vmf_insert_page_mkwrite(vmf, &folio->page, true);
 #ifdef CONFIG_FS_DAX_PMD
 	else if (order == PMD_ORDER)
-		ret = vmf_insert_pfn_pmd(vmf, pfn, FAULT_FLAG_WRITE);
+		ret = vmf_insert_folio_pmd(vmf, folio, FAULT_FLAG_WRITE);
 #endif
 	else
 		ret = VM_FAULT_FALLBACK;
+	folio_put(folio);
 	dax_unlock_entry(&xas, entry);
 	trace_dax_insert_pfn_mkwrite(mapping->host, vmf, ret);
 	return ret;