f2fs crypto: f2fs_page_crypto() doesn't need a encryption context

This patch adopts:
	ext4 crypto: ext4_page_crypto() doesn't need a encryption context

Since ext4_page_crypto() doesn't need an encryption context (at least
not any more), this allows us to simplify a number function signature
and also allows us to avoid needing to allocate a context in
ext4_block_write_begin().  It also means we no longer need a separate
ext4_decrypt_one() function.
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/crypto.c

@@ -156,7 +156,7 @@ static void completion_pages(struct work_struct *work)
 
 	bio_for_each_segment_all(bv, bio, i) {
 		struct page *page = bv->bv_page;
-		int ret = f2fs_decrypt(ctx, page);
+		int ret = f2fs_decrypt(page);
 
 		if (ret) {
 			WARN_ON_ONCE(1);
@@ -320,8 +320,7 @@ typedef enum {
 	F2FS_ENCRYPT,
 } f2fs_direction_t;
 
-static int f2fs_page_crypto(struct f2fs_crypto_ctx *ctx,
-				struct inode *inode,
+static int f2fs_page_crypto(struct inode *inode,
 				f2fs_direction_t rw,
 				pgoff_t index,
 				struct page *src_page,
@@ -418,7 +417,7 @@ struct page *f2fs_encrypt(struct inode *inode,
 		goto err_out;
 
 	ctx->w.control_page = plaintext_page;
-	err = f2fs_page_crypto(ctx, inode, F2FS_ENCRYPT, plaintext_page->index,
+	err = f2fs_page_crypto(inode, F2FS_ENCRYPT, plaintext_page->index,
 					plaintext_page, ciphertext_page);
 	if (err) {
 		ciphertext_page = ERR_PTR(err);
@@ -446,30 +445,14 @@ struct page *f2fs_encrypt(struct inode *inode,
  *
  * Return: Zero on success, non-zero otherwise.
  */
-int f2fs_decrypt(struct f2fs_crypto_ctx *ctx, struct page *page)
+int f2fs_decrypt(struct page *page)
 {
 	BUG_ON(!PageLocked(page));
 
-	return f2fs_page_crypto(ctx, page->mapping->host,
+	return f2fs_page_crypto(page->mapping->host,
 				F2FS_DECRYPT, page->index, page, page);
 }
 
-/*
- * Convenience function which takes care of allocating and
- * deallocating the encryption context
- */
-int f2fs_decrypt_one(struct inode *inode, struct page *page)
-{
-	struct f2fs_crypto_ctx *ctx = f2fs_get_crypto_ctx(inode);
-	int ret;
-
-	if (IS_ERR(ctx))
-		return PTR_ERR(ctx);
-	ret = f2fs_decrypt(ctx, page);
-	f2fs_release_crypto_ctx(ctx);
-	return ret;
-}
-
 bool f2fs_valid_contents_enc_mode(uint32_t mode)
 {
 	return (mode == F2FS_ENCRYPTION_MODE_AES_256_XTS);

fs/f2fs/data.c

@@ -1592,7 +1592,7 @@ static int f2fs_write_begin(struct file *file, struct address_space *mapping,
 
 		/* avoid symlink page */
 		if (f2fs_encrypted_inode(inode) && S_ISREG(inode->i_mode)) {
-			err = f2fs_decrypt_one(inode, page);
+			err = f2fs_decrypt(page);
 			if (err)
 				goto fail;
 		}

fs/f2fs/f2fs.h

@@ -2213,8 +2213,7 @@ uint32_t f2fs_validate_encryption_key_size(uint32_t, uint32_t);
 struct f2fs_crypto_ctx *f2fs_get_crypto_ctx(struct inode *);
 void f2fs_release_crypto_ctx(struct f2fs_crypto_ctx *);
 struct page *f2fs_encrypt(struct inode *, struct page *);
-int f2fs_decrypt(struct f2fs_crypto_ctx *, struct page *);
-int f2fs_decrypt_one(struct inode *, struct page *);
+int f2fs_decrypt(struct page *);
 void f2fs_end_io_crypto_work(struct f2fs_crypto_ctx *, struct bio *);
 
 /* crypto_key.c */