ecryptfs: Convert ecryptfs_read_lower_page_segment() to take a folio

All callers have a folio, so pass it in and use it directly.  This will
not work for large folios, but I doubt anybody wants to use large folios
with ecryptfs.

Signed-off-by: Matthew Wilcox (Oracle) <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Christian Brauner <[email protected]>

Author: Matthew Wilcox (Oracle)

fs/ecryptfs/ecryptfs_kernel.h

@@ -658,7 +658,7 @@ int ecryptfs_write_lower_page_segment(struct inode *ecryptfs_inode,
 int ecryptfs_write(struct inode *inode, char *data, loff_t offset, size_t size);
 int ecryptfs_read_lower(char *data, loff_t offset, size_t size,
 			struct inode *ecryptfs_inode);
-int ecryptfs_read_lower_page_segment(struct page *page_for_ecryptfs,
+int ecryptfs_read_lower_page_segment(struct folio *folio_for_ecryptfs,
 				     pgoff_t page_index,
 				     size_t offset_in_page, size_t size,
 				     struct inode *ecryptfs_inode);

fs/ecryptfs/mmap.c

@@ -150,7 +150,7 @@ ecryptfs_copy_up_encrypted_with_header(struct folio *folio,
 				 - crypt_stat->metadata_size);
 
 			rc = ecryptfs_read_lower_page_segment(
-				&folio->page, (lower_offset >> PAGE_SHIFT),
+				folio, (lower_offset >> PAGE_SHIFT),
 				(lower_offset & ~PAGE_MASK),
 				crypt_stat->extent_size, folio->mapping->host);
 			if (rc) {
@@ -184,9 +184,8 @@ static int ecryptfs_read_folio(struct file *file, struct folio *folio)
 	int err = 0;
 
 	if (!crypt_stat || !(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
-		err = ecryptfs_read_lower_page_segment(&folio->page, folio->index, 0,
-						      folio_size(folio),
-						      inode);
+		err = ecryptfs_read_lower_page_segment(folio, folio->index, 0,
+				folio_size(folio), inode);
 	} else if (crypt_stat->flags & ECRYPTFS_VIEW_AS_ENCRYPTED) {
 		if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR) {
 			err = ecryptfs_copy_up_encrypted_with_header(folio,
@@ -201,7 +200,7 @@ static int ecryptfs_read_folio(struct file *file, struct folio *folio)
 			}
 
 		} else {
-			err = ecryptfs_read_lower_page_segment(&folio->page,
+			err = ecryptfs_read_lower_page_segment(folio,
 					folio->index, 0, folio_size(folio),
 					inode);
 			if (err) {
@@ -279,7 +278,7 @@ static int ecryptfs_write_begin(struct file *file,
 
 		if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
 			rc = ecryptfs_read_lower_page_segment(
-				&folio->page, index, 0, PAGE_SIZE, mapping->host);
+				folio, index, 0, PAGE_SIZE, mapping->host);
 			if (rc) {
 				printk(KERN_ERR "%s: Error attempting to read "
 				       "lower page segment; rc = [%d]\n",
@@ -305,7 +304,7 @@ static int ecryptfs_write_begin(struct file *file,
 				folio_mark_uptodate(folio);
 			} else {
 				rc = ecryptfs_read_lower_page_segment(
-					&folio->page, index, 0, PAGE_SIZE,
+					folio, index, 0, PAGE_SIZE,
 					mapping->host);
 				if (rc) {
 					printk(KERN_ERR "%s: Error reading "

fs/ecryptfs/read_write.c

@@ -228,7 +228,7 @@ int ecryptfs_read_lower(char *data, loff_t offset, size_t size,
 
 /**
  * ecryptfs_read_lower_page_segment
- * @page_for_ecryptfs: The page into which data for eCryptfs will be
+ * @folio_for_ecryptfs: The folio into which data for eCryptfs will be
  *                     written
  * @page_index: Page index in @page_for_ecryptfs from which to start
  *		writing
@@ -243,7 +243,7 @@ int ecryptfs_read_lower(char *data, loff_t offset, size_t size,
  *
  * Returns zero on success; non-zero otherwise
  */
-int ecryptfs_read_lower_page_segment(struct page *page_for_ecryptfs,
+int ecryptfs_read_lower_page_segment(struct folio *folio_for_ecryptfs,
 				     pgoff_t page_index,
 				     size_t offset_in_page, size_t size,
 				     struct inode *ecryptfs_inode)
@@ -252,12 +252,12 @@ int ecryptfs_read_lower_page_segment(struct page *page_for_ecryptfs,
 	loff_t offset;
 	int rc;
 
-	offset = ((((loff_t)page_index) << PAGE_SHIFT) + offset_in_page);
-	virt = kmap_local_page(page_for_ecryptfs);
+	offset = (loff_t)page_index * PAGE_SIZE + offset_in_page;
+	virt = kmap_local_folio(folio_for_ecryptfs, 0);
 	rc = ecryptfs_read_lower(virt, offset, size, ecryptfs_inode);
 	if (rc > 0)
 		rc = 0;
 	kunmap_local(virt);
-	flush_dcache_page(page_for_ecryptfs);
+	flush_dcache_folio(folio_for_ecryptfs);
 	return rc;
 }