fscrypt: rename fscrypt_do_page_crypto() to fscrypt_crypt_block()

fscrypt_do_page_crypto() only does a single encryption or decryption
operation, with a single logical block number (single IV).  So it
actually operates on a filesystem block, not a "page" per se.  To
reflect this, rename it to fscrypt_crypt_block().
Reviewed-by: Chandan Rajendra <chandan@linux.ibm.com>
Signed-off-by: Eric Biggers <ebiggers@google.com>

fs/crypto/bio.c

@@ -83,7 +83,7 @@ int fscrypt_zeroout_range(const struct inode *inode, pgoff_t lblk,
 		return -ENOMEM;
 
 	while (len--) {
-		err = fscrypt_do_page_crypto(inode, FS_ENCRYPT, lblk,
+		err = fscrypt_crypt_block(inode, FS_ENCRYPT, lblk,
 					  ZERO_PAGE(0), ciphertext_page,
 					  PAGE_SIZE, 0, GFP_NOFS);
 		if (err)

fs/crypto/crypto.c

@@ -148,7 +148,8 @@ void fscrypt_generate_iv(union fscrypt_iv *iv, u64 lblk_num,
 		crypto_cipher_encrypt_one(ci->ci_essiv_tfm, iv->raw, iv->raw);
 }
 
-int fscrypt_do_page_crypto(const struct inode *inode, fscrypt_direction_t rw,
+/* Encrypt or decrypt a single filesystem block of file contents */
+int fscrypt_crypt_block(const struct inode *inode, fscrypt_direction_t rw,
 			u64 lblk_num, struct page *src_page,
 			struct page *dest_page, unsigned int len,
 			unsigned int offs, gfp_t gfp_flags)
@@ -228,7 +229,7 @@ struct page *fscrypt_encrypt_page(const struct inode *inode,
 
 	if (inode->i_sb->s_cop->flags & FS_CFLG_OWN_PAGES) {
 		/* with inplace-encryption we just encrypt the page */
-		err = fscrypt_do_page_crypto(inode, FS_ENCRYPT, lblk_num, page,
+		err = fscrypt_crypt_block(inode, FS_ENCRYPT, lblk_num, page,
 					  ciphertext_page, len, offs,
 					  gfp_flags);
 		if (err)
@@ -244,9 +245,8 @@ struct page *fscrypt_encrypt_page(const struct inode *inode,
 	if (!ciphertext_page)
 		return ERR_PTR(-ENOMEM);
 
-	err = fscrypt_do_page_crypto(inode, FS_ENCRYPT, lblk_num,
-				     page, ciphertext_page, len, offs,
-				     gfp_flags);
+	err = fscrypt_crypt_block(inode, FS_ENCRYPT, lblk_num, page,
+				  ciphertext_page, len, offs, gfp_flags);
 	if (err) {
 		fscrypt_free_bounce_page(ciphertext_page);
 		return ERR_PTR(err);
@@ -278,7 +278,7 @@ int fscrypt_decrypt_page(const struct inode *inode, struct page *page,
 	if (!(inode->i_sb->s_cop->flags & FS_CFLG_OWN_PAGES))
 		BUG_ON(!PageLocked(page));
 
-	return fscrypt_do_page_crypto(inode, FS_DECRYPT, lblk_num, page, page,
+	return fscrypt_crypt_block(inode, FS_DECRYPT, lblk_num, page, page,
 				   len, offs, GFP_NOFS);
 }
 EXPORT_SYMBOL(fscrypt_decrypt_page);

fs/crypto/fscrypt_private.h

@@ -116,10 +116,9 @@ static inline bool fscrypt_valid_enc_modes(u32 contents_mode,
 /* crypto.c */
 extern struct kmem_cache *fscrypt_info_cachep;
 extern int fscrypt_initialize(unsigned int cop_flags);
-extern int fscrypt_do_page_crypto(const struct inode *inode,
+extern int fscrypt_crypt_block(const struct inode *inode,
 			       fscrypt_direction_t rw, u64 lblk_num,
-				  struct page *src_page,
-				  struct page *dest_page,
+			       struct page *src_page, struct page *dest_page,
 			       unsigned int len, unsigned int offs,
 			       gfp_t gfp_flags);
 extern struct page *fscrypt_alloc_bounce_page(gfp_t gfp_flags);