fscrypt: Change fscrypt_encrypt_pagecache_blocks() to take a folio

ext4 and ceph already have a folio to pass; f2fs needs to be properly
converted but this will do for now.  This removes a reference
to page->index and page->mapping as well as removing a call to
compound_head().

Signed-off-by: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Link: https://lore.kernel.org/r/20250304170224.523141-1-willy@infradead.org
Acked-by: Eric Biggers <ebiggers@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>

Author: Matthew Wilcox (Oracle)

fs/ceph/addr.c

@@ -786,7 +786,7 @@ static int write_folio_nounlock(struct folio *folio,
 	ceph_fscache_write_to_cache(inode, page_off, len, caching);
 
 	if (IS_ENCRYPTED(inode)) {
-		bounce_page = fscrypt_encrypt_pagecache_blocks(&folio->page,
+		bounce_page = fscrypt_encrypt_pagecache_blocks(folio,
 						    CEPH_FSCRYPT_BLOCK_SIZE, 0,
 						    GFP_NOFS);
 		if (IS_ERR(bounce_page)) {
@@ -1248,7 +1248,7 @@ static inline int move_dirty_folio_in_page_array(struct address_space *mapping,
 	gfp_t gfp_flags = ceph_wbc->locked_pages ? GFP_NOWAIT : GFP_NOFS;
 
 	if (IS_ENCRYPTED(inode)) {
-		pages[index] = fscrypt_encrypt_pagecache_blocks(&folio->page,
+		pages[index] = fscrypt_encrypt_pagecache_blocks(folio,
 								PAGE_SIZE,
 								0,
 								gfp_flags);

fs/crypto/crypto.c

@@ -153,8 +153,8 @@ int fscrypt_crypt_data_unit(const struct fscrypt_inode_info *ci,
 }
 
 /**
- * fscrypt_encrypt_pagecache_blocks() - Encrypt data from a pagecache page
- * @page: the locked pagecache page containing the data to encrypt
+ * fscrypt_encrypt_pagecache_blocks() - Encrypt data from a pagecache folio
+ * @folio: the locked pagecache folio containing the data to encrypt
  * @len: size of the data to encrypt, in bytes
  * @offs: offset within @page of the data to encrypt, in bytes
  * @gfp_flags: memory allocation flags; see details below
@@ -177,23 +177,21 @@ int fscrypt_crypt_data_unit(const struct fscrypt_inode_info *ci,
  *
  * Return: the new encrypted bounce page on success; an ERR_PTR() on failure
  */
-struct page *fscrypt_encrypt_pagecache_blocks(struct page *page,
-					      unsigned int len,
-					      unsigned int offs,
-					      gfp_t gfp_flags)
-
+struct page *fscrypt_encrypt_pagecache_blocks(struct folio *folio,
+		size_t len, size_t offs, gfp_t gfp_flags)
 {
-	const struct inode *inode = page->mapping->host;
+	const struct inode *inode = folio->mapping->host;
 	const struct fscrypt_inode_info *ci = inode->i_crypt_info;
 	const unsigned int du_bits = ci->ci_data_unit_bits;
 	const unsigned int du_size = 1U << du_bits;
 	struct page *ciphertext_page;
-	u64 index = ((u64)page->index << (PAGE_SHIFT - du_bits)) +
+	u64 index = ((u64)folio->index << (PAGE_SHIFT - du_bits)) +
 		    (offs >> du_bits);
 	unsigned int i;
 	int err;
 
-	if (WARN_ON_ONCE(!PageLocked(page)))
+	VM_BUG_ON_FOLIO(folio_test_large(folio), folio);
+	if (WARN_ON_ONCE(!folio_test_locked(folio)))
 		return ERR_PTR(-EINVAL);
 
 	if (WARN_ON_ONCE(len <= 0 || !IS_ALIGNED(len | offs, du_size)))
@@ -205,15 +203,15 @@ struct page *fscrypt_encrypt_pagecache_blocks(struct page *page,
 
 	for (i = offs; i < offs + len; i += du_size, index++) {
 		err = fscrypt_crypt_data_unit(ci, FS_ENCRYPT, index,
-					      page, ciphertext_page,
+					      &folio->page, ciphertext_page,
 					      du_size, i, gfp_flags);
 		if (err) {
 			fscrypt_free_bounce_page(ciphertext_page);
 			return ERR_PTR(err);
 		}
 	}
 	SetPagePrivate(ciphertext_page);
-	set_page_private(ciphertext_page, (unsigned long)page);
+	set_page_private(ciphertext_page, (unsigned long)folio);
 	return ciphertext_page;
 }
 EXPORT_SYMBOL(fscrypt_encrypt_pagecache_blocks);

fs/ext4/page-io.c

@@ -522,7 +522,7 @@ int ext4_bio_write_folio(struct ext4_io_submit *io, struct folio *folio,
 		if (io->io_bio)
 			gfp_flags = GFP_NOWAIT | __GFP_NOWARN;
 	retry_encrypt:
-		bounce_page = fscrypt_encrypt_pagecache_blocks(&folio->page,
+		bounce_page = fscrypt_encrypt_pagecache_blocks(folio,
 					enc_bytes, 0, gfp_flags);
 		if (IS_ERR(bounce_page)) {
 			ret = PTR_ERR(bounce_page);

fs/f2fs/data.c

@@ -2500,7 +2500,7 @@ int f2fs_encrypt_one_page(struct f2fs_io_info *fio)
 		return 0;
 
 retry_encrypt:
-	fio->encrypted_page = fscrypt_encrypt_pagecache_blocks(page,
+	fio->encrypted_page = fscrypt_encrypt_pagecache_blocks(page_folio(page),
 					PAGE_SIZE, 0, gfp_flags);
 	if (IS_ERR(fio->encrypted_page)) {
 		/* flush pending IOs and wait for a while in the ENOMEM case */

include/linux/fscrypt.h

@@ -310,10 +310,8 @@ static inline void fscrypt_prepare_dentry(struct dentry *dentry,
 /* crypto.c */
 void fscrypt_enqueue_decrypt_work(struct work_struct *);
 
-struct page *fscrypt_encrypt_pagecache_blocks(struct page *page,
-					      unsigned int len,
-					      unsigned int offs,
-					      gfp_t gfp_flags);
+struct page *fscrypt_encrypt_pagecache_blocks(struct folio *folio,
+		size_t len, size_t offs, gfp_t gfp_flags);
 int fscrypt_encrypt_block_inplace(const struct inode *inode, struct page *page,
 				  unsigned int len, unsigned int offs,
 				  u64 lblk_num, gfp_t gfp_flags);
@@ -480,10 +478,8 @@ static inline void fscrypt_enqueue_decrypt_work(struct work_struct *work)
 {
 }
 
-static inline struct page *fscrypt_encrypt_pagecache_blocks(struct page *page,
-							    unsigned int len,
-							    unsigned int offs,
-							    gfp_t gfp_flags)
+static inline struct page *fscrypt_encrypt_pagecache_blocks(struct folio *folio,
+		size_t len, size_t offs, gfp_t gfp_flags)
 {
 	return ERR_PTR(-EOPNOTSUPP);
 }