ecryptfs: Convert ecryptfs_decrypt_page() to take a folio

Both callers have a folio, so pass it in and use it throughout.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Link: https://lore.kernel.org/r/20241025190822.1319162-9-willy@infradead.org
Signed-off-by: Christian Brauner <brauner@kernel.org>

Author: Matthew Wilcox (Oracle)

fs/ecryptfs/crypto.c

@@ -461,7 +461,7 @@ int ecryptfs_encrypt_page(struct folio *folio)
 
 /**
  * ecryptfs_decrypt_page
- * @page: Page mapped from the eCryptfs inode for the file; data read
+ * @folio: Folio mapped from the eCryptfs inode for the file; data read
  *        and decrypted from the lower file will be written into this
  *        page
  *
@@ -475,7 +475,7 @@ int ecryptfs_encrypt_page(struct folio *folio)
  *
  * Returns zero on success; negative on error
  */
-int ecryptfs_decrypt_page(struct page *page)
+int ecryptfs_decrypt_page(struct folio *folio)
 {
 	struct inode *ecryptfs_inode;
 	struct ecryptfs_crypt_stat *crypt_stat;
@@ -484,13 +484,13 @@ int ecryptfs_decrypt_page(struct page *page)
 	loff_t lower_offset;
 	int rc = 0;
 
-	ecryptfs_inode = page->mapping->host;
+	ecryptfs_inode = folio->mapping->host;
 	crypt_stat =
 		&(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat);
 	BUG_ON(!(crypt_stat->flags & ECRYPTFS_ENCRYPTED));
 
-	lower_offset = lower_offset_for_page(crypt_stat, page);
-	page_virt = kmap_local_page(page);
+	lower_offset = lower_offset_for_page(crypt_stat, &folio->page);
+	page_virt = kmap_local_folio(folio, 0);
 	rc = ecryptfs_read_lower(page_virt, lower_offset, PAGE_SIZE,
 				 ecryptfs_inode);
 	kunmap_local(page_virt);
@@ -504,6 +504,7 @@ int ecryptfs_decrypt_page(struct page *page)
 	for (extent_offset = 0;
 	     extent_offset < (PAGE_SIZE / crypt_stat->extent_size);
 	     extent_offset++) {
+		struct page *page = folio_page(folio, 0);
 		rc = crypt_extent(crypt_stat, page, page,
 				  extent_offset, DECRYPT);
 		if (rc) {

fs/ecryptfs/ecryptfs_kernel.h

@@ -570,7 +570,7 @@ void ecryptfs_destroy_mount_crypt_stat(
 int ecryptfs_init_crypt_ctx(struct ecryptfs_crypt_stat *crypt_stat);
 int ecryptfs_write_inode_size_to_metadata(struct inode *ecryptfs_inode);
 int ecryptfs_encrypt_page(struct folio *folio);
-int ecryptfs_decrypt_page(struct page *page);
+int ecryptfs_decrypt_page(struct folio *folio);
 int ecryptfs_write_metadata(struct dentry *ecryptfs_dentry,
 			    struct inode *ecryptfs_inode);
 int ecryptfs_read_metadata(struct dentry *ecryptfs_dentry);

fs/ecryptfs/mmap.c

@@ -194,7 +194,7 @@ static int ecryptfs_read_folio(struct file *file, struct folio *folio)
 			}
 		}
 	} else {
-		err = ecryptfs_decrypt_page(&folio->page);
+		err = ecryptfs_decrypt_page(folio);
 		if (err) {
 			ecryptfs_printk(KERN_ERR, "Error decrypting page; "
 					"err = [%d]\n", err);
@@ -305,7 +305,7 @@ static int ecryptfs_write_begin(struct file *file,
 				folio_zero_range(folio, 0, PAGE_SIZE);
 				folio_mark_uptodate(folio);
 			} else if (len < PAGE_SIZE) {
-				rc = ecryptfs_decrypt_page(&folio->page);
+				rc = ecryptfs_decrypt_page(folio);
 				if (rc) {
 					printk(KERN_ERR "%s: Error decrypting "
 					       "page at index [%ld]; "