ecryptfs: Convert ecryptfs_write() to use a folio

Remove ecryptfs_get_locked_page() and call read_mapping_folio()
directly.  Use the folio throught this function.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Link: https://lore.kernel.org/r/20241025190822.1319162-6-willy@infradead.org
Reviewed-by: Pankaj Raghav <p.raghav@samsung.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>

Author: Matthew Wilcox (Oracle)

fs/ecryptfs/ecryptfs_kernel.h

@@ -662,7 +662,6 @@ 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);
-struct page *ecryptfs_get_locked_page(struct inode *inode, loff_t index);
 int ecryptfs_parse_packet_length(unsigned char *data, size_t *size,
 				 size_t *length_size);
 int ecryptfs_write_packet_length(char *dest, size_t size,

fs/ecryptfs/mmap.c

@@ -22,22 +22,6 @@
 #include <linux/unaligned.h>
 #include "ecryptfs_kernel.h"
 
-/*
- * ecryptfs_get_locked_page
- *
- * Get one page from cache or lower f/s, return error otherwise.
- *
- * Returns locked and up-to-date page (if ok), with increased
- * refcnt.
- */
-struct page *ecryptfs_get_locked_page(struct inode *inode, loff_t index)
-{
-	struct page *page = read_mapping_page(inode->i_mapping, index, NULL);
-	if (!IS_ERR(page))
-		lock_page(page);
-	return page;
-}
-
 /*
  * This is where we encrypt the data and pass the encrypted data to
  * the lower filesystem.  In OpenPGP-compatible mode, we operate on

fs/ecryptfs/read_write.c

@@ -93,7 +93,6 @@ int ecryptfs_write_lower_page_segment(struct inode *ecryptfs_inode,
 int ecryptfs_write(struct inode *ecryptfs_inode, char *data, loff_t offset,
 		   size_t size)
 {
-	struct page *ecryptfs_page;
 	struct ecryptfs_crypt_stat *crypt_stat;
 	char *ecryptfs_page_virt;
 	loff_t ecryptfs_file_size = i_size_read(ecryptfs_inode);
@@ -111,6 +110,7 @@ int ecryptfs_write(struct inode *ecryptfs_inode, char *data, loff_t offset,
 	else
 		pos = offset;
 	while (pos < (offset + size)) {
+		struct folio *ecryptfs_folio;
 		pgoff_t ecryptfs_page_idx = (pos >> PAGE_SHIFT);
 		size_t start_offset_in_page = (pos & ~PAGE_MASK);
 		size_t num_bytes = (PAGE_SIZE - start_offset_in_page);
@@ -130,17 +130,18 @@ int ecryptfs_write(struct inode *ecryptfs_inode, char *data, loff_t offset,
 			if (num_bytes > total_remaining_zeros)
 				num_bytes = total_remaining_zeros;
 		}
-		ecryptfs_page = ecryptfs_get_locked_page(ecryptfs_inode,
-							 ecryptfs_page_idx);
-		if (IS_ERR(ecryptfs_page)) {
-			rc = PTR_ERR(ecryptfs_page);
+		ecryptfs_folio = read_mapping_folio(ecryptfs_inode->i_mapping,
+				ecryptfs_page_idx, NULL);
+		if (IS_ERR(ecryptfs_folio)) {
+			rc = PTR_ERR(ecryptfs_folio);
 			printk(KERN_ERR "%s: Error getting page at "
 			       "index [%ld] from eCryptfs inode "
 			       "mapping; rc = [%d]\n", __func__,
 			       ecryptfs_page_idx, rc);
 			goto out;
 		}
-		ecryptfs_page_virt = kmap_local_page(ecryptfs_page);
+		folio_lock(ecryptfs_folio);
+		ecryptfs_page_virt = kmap_local_folio(ecryptfs_folio, 0);
 
 		/*
 		 * pos: where we're now writing, offset: where the request was
@@ -164,17 +165,17 @@ int ecryptfs_write(struct inode *ecryptfs_inode, char *data, loff_t offset,
 			data_offset += num_bytes;
 		}
 		kunmap_local(ecryptfs_page_virt);
-		flush_dcache_page(ecryptfs_page);
-		SetPageUptodate(ecryptfs_page);
-		unlock_page(ecryptfs_page);
+		flush_dcache_folio(ecryptfs_folio);
+		folio_mark_uptodate(ecryptfs_folio);
+		folio_unlock(ecryptfs_folio);
 		if (crypt_stat->flags & ECRYPTFS_ENCRYPTED)
-			rc = ecryptfs_encrypt_page(ecryptfs_page);
+			rc = ecryptfs_encrypt_page(&ecryptfs_folio->page);
 		else
 			rc = ecryptfs_write_lower_page_segment(ecryptfs_inode,
-						ecryptfs_page,
+						&ecryptfs_folio->page,
 						start_offset_in_page,
 						data_offset);
-		put_page(ecryptfs_page);
+		folio_put(ecryptfs_folio);
 		if (rc) {
 			printk(KERN_ERR "%s: Error encrypting "
 			       "page; rc = [%d]\n", __func__, rc);