[PATCH v2 16/17] fscrypt: Merge bio.c and inline_crypt.c into block.c

[Eric Biggers <ebiggers@kernel.org>]

Now that fscrypt always uses blk-crypto on block-based filesystems,
there's no meaningful difference between bio.c and inline_crypt.c.
Therefore merge the two files into one named block.c.

Note: I didn't carry over bio.c's "Copyright (C) 2015, Motorola
Mobility", as none of the code that applied to remained.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
---
 fs/crypto/Makefile                    |   3 +-
 fs/crypto/bio.c                       | 100 --------------------------
 fs/crypto/{inline_crypt.c => block.c} |  96 +++++++++++++++++++++++--
 fs/crypto/fscrypt_private.h           |   2 +-
 include/linux/fscrypt.h               |  22 +++---
 5 files changed, 101 insertions(+), 122 deletions(-)
 delete mode 100644 fs/crypto/bio.c
 rename fs/crypto/{inline_crypt.c => block.c} (79%)

diff --git a/fs/crypto/Makefile b/fs/crypto/Makefile
index 652c7180ec6d..b03e02f0f09d 100644
--- a/fs/crypto/Makefile
+++ b/fs/crypto/Makefile
@@ -10,5 +10,4 @@ fscrypto-y := crypto.o \
 	      keysetup_v1.o \
 	      policy.o
 
-fscrypto-$(CONFIG_BLOCK) += bio.o
-fscrypto-$(CONFIG_FS_ENCRYPTION_INLINE_CRYPT) += inline_crypt.o
+fscrypto-$(CONFIG_BLOCK) += block.o
diff --git a/fs/crypto/bio.c b/fs/crypto/bio.c
deleted file mode 100644
index db095258cfca..000000000000
--- a/fs/crypto/bio.c
+++ /dev/null
@@ -1,100 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-/*
- * Utility functions for file contents encryption/decryption on
- * block device-based filesystems.
- *
- * Copyright (C) 2015, Google, Inc.
- * Copyright (C) 2015, Motorola Mobility
- */
-
-#include <linux/bio.h>
-#include <linux/export.h>
-#include <linux/module.h>
-#include <linux/namei.h>
-#include <linux/pagemap.h>
-
-#include "fscrypt_private.h"
-
-struct fscrypt_zero_done {
-	atomic_t		pending;
-	blk_status_t		status;
-	struct completion	done;
-};
-
-static void fscrypt_zeroout_range_done(struct fscrypt_zero_done *done)
-{
-	if (atomic_dec_and_test(&done->pending))
-		complete(&done->done);
-}
-
-static void fscrypt_zeroout_range_end_io(struct bio *bio)
-{
-	struct fscrypt_zero_done *done = bio->bi_private;
-
-	if (bio->bi_status)
-		cmpxchg(&done->status, 0, bio->bi_status);
-	fscrypt_zeroout_range_done(done);
-	bio_put(bio);
-}
-
-/**
- * fscrypt_zeroout_range() - zero out a range of blocks in an encrypted file
- * @inode: the file's inode
- * @pos: the first file position (in bytes) to zero out
- * @sector: the first sector to zero out
- * @len: bytes to zero out
- *
- * Zero out filesystem blocks in an encrypted regular file on-disk, i.e. write
- * ciphertext blocks which decrypt to the all-zeroes block.  The blocks must be
- * both logically and physically contiguous.  It's also assumed that the
- * filesystem only uses a single block device, ->s_bdev.  @len must be a
- * multiple of the file system logical block size.
- *
- * Note that since each block uses a different IV, this involves writing a
- * different ciphertext to each block; we can't simply reuse the same one.
- *
- * Return: 0 on success; -errno on failure.
- */
-int fscrypt_zeroout_range(const struct inode *inode, loff_t pos,
-			  sector_t sector, u64 len)
-{
-	struct fscrypt_zero_done done = {
-		.pending	= ATOMIC_INIT(1),
-		.done		= COMPLETION_INITIALIZER_ONSTACK(done.done),
-	};
-
-	if (len == 0)
-		return 0;
-
-	do {
-		struct bio *bio;
-		unsigned int n;
-
-		bio = bio_alloc(inode->i_sb->s_bdev, BIO_MAX_VECS, REQ_OP_WRITE,
-				GFP_NOFS);
-		bio->bi_iter.bi_sector = sector;
-		bio->bi_private = &done;
-		bio->bi_end_io = fscrypt_zeroout_range_end_io;
-		fscrypt_set_bio_crypt_ctx(bio, inode, pos, GFP_NOFS);
-
-		for (n = 0; n < BIO_MAX_VECS; n++) {
-			unsigned int bytes_this_page = min(len, PAGE_SIZE);
-
-			__bio_add_page(bio, ZERO_PAGE(0), bytes_this_page, 0);
-			len -= bytes_this_page;
-			pos += bytes_this_page;
-			sector += (bytes_this_page >> SECTOR_SHIFT);
-			if (!len || !fscrypt_mergeable_bio(bio, inode, pos))
-				break;
-		}
-
-		atomic_inc(&done.pending);
-		blk_crypto_submit_bio(bio);
-	} while (len);
-
-	fscrypt_zeroout_range_done(&done);
-
-	wait_for_completion(&done.done);
-	return blk_status_to_errno(done.status);
-}
-EXPORT_SYMBOL(fscrypt_zeroout_range);
diff --git a/fs/crypto/inline_crypt.c b/fs/crypto/block.c
similarity index 79%
rename from fs/crypto/inline_crypt.c
rename to fs/crypto/block.c
index 14c8af322c2f..059b7ecc70ea 100644
--- a/fs/crypto/inline_crypt.c
+++ b/fs/crypto/block.c
@@ -1,20 +1,20 @@
 // SPDX-License-Identifier: GPL-2.0
 /*
- * Inline encryption support for fscrypt
+ * File contents en/decryption on block-based filesystems
  *
  * Copyright 2019 Google LLC
  */
 
 /*
- * With "inline encryption", the block layer handles the decryption/encryption
- * as part of the bio, instead of the filesystem doing the crypto itself via
- * crypto API.  See Documentation/block/inline-encryption.rst.  fscrypt still
- * provides the key and IV to use.
+ * This file implements fscrypt's file contents en/decryption using blk-crypto
+ * (Documentation/block/inline-encryption.rst).  fscrypt assigns a bio_crypt_ctx
+ * with a key and IV to each bio, and the block layer does the en/decryption.
+ *
+ * This file's exported functions are called only by block-based filesystems.
  */
 
 #include <linux/blk-crypto.h>
 #include <linux/blkdev.h>
-#include <linux/buffer_head.h>
 #include <linux/export.h>
 #include <linux/sched/mm.h>
 #include <linux/slab.h>
@@ -341,3 +341,87 @@ u64 fscrypt_limit_io_blocks(const struct inode *inode, u64 lblk, u64 nr_blocks)
 	return min_t(u64, nr_blocks, (u64)U32_MAX + 1 - dun);
 }
 EXPORT_SYMBOL_GPL(fscrypt_limit_io_blocks);
+
+struct fscrypt_zero_done {
+	atomic_t		pending;
+	blk_status_t		status;
+	struct completion	done;
+};
+
+static void fscrypt_zeroout_range_done(struct fscrypt_zero_done *done)
+{
+	if (atomic_dec_and_test(&done->pending))
+		complete(&done->done);
+}
+
+static void fscrypt_zeroout_range_end_io(struct bio *bio)
+{
+	struct fscrypt_zero_done *done = bio->bi_private;
+
+	if (bio->bi_status)
+		cmpxchg(&done->status, 0, bio->bi_status);
+	fscrypt_zeroout_range_done(done);
+	bio_put(bio);
+}
+
+/**
+ * fscrypt_zeroout_range() - zero out a range of blocks in an encrypted file
+ * @inode: the file's inode
+ * @pos: the first file position (in bytes) to zero out
+ * @sector: the first sector to zero out
+ * @len: bytes to zero out
+ *
+ * Zero out filesystem blocks in an encrypted regular file on-disk, i.e. write
+ * ciphertext blocks which decrypt to the all-zeroes block.  The blocks must be
+ * both logically and physically contiguous.  It's also assumed that the
+ * filesystem only uses a single block device, ->s_bdev.  @len must be a
+ * multiple of the file system logical block size.
+ *
+ * Note that since each block uses a different IV, this involves writing a
+ * different ciphertext to each block; we can't simply reuse the same one.
+ *
+ * Return: 0 on success; -errno on failure.
+ */
+int fscrypt_zeroout_range(const struct inode *inode, loff_t pos,
+			  sector_t sector, u64 len)
+{
+	struct fscrypt_zero_done done = {
+		.pending	= ATOMIC_INIT(1),
+		.done		= COMPLETION_INITIALIZER_ONSTACK(done.done),
+	};
+
+	if (len == 0)
+		return 0;
+
+	do {
+		struct bio *bio;
+		unsigned int n;
+
+		bio = bio_alloc(inode->i_sb->s_bdev, BIO_MAX_VECS, REQ_OP_WRITE,
+				GFP_NOFS);
+		bio->bi_iter.bi_sector = sector;
+		bio->bi_private = &done;
+		bio->bi_end_io = fscrypt_zeroout_range_end_io;
+		fscrypt_set_bio_crypt_ctx(bio, inode, pos, GFP_NOFS);
+
+		for (n = 0; n < BIO_MAX_VECS; n++) {
+			unsigned int bytes_this_page = min(len, PAGE_SIZE);
+
+			__bio_add_page(bio, ZERO_PAGE(0), bytes_this_page, 0);
+			len -= bytes_this_page;
+			pos += bytes_this_page;
+			sector += (bytes_this_page >> SECTOR_SHIFT);
+			if (!len || !fscrypt_mergeable_bio(bio, inode, pos))
+				break;
+		}
+
+		atomic_inc(&done.pending);
+		blk_crypto_submit_bio(bio);
+	} while (len);
+
+	fscrypt_zeroout_range_done(&done);
+
+	wait_for_completion(&done.done);
+	return blk_status_to_errno(done.status);
+}
+EXPORT_SYMBOL(fscrypt_zeroout_range);
diff --git a/fs/crypto/fscrypt_private.h b/fs/crypto/fscrypt_private.h
index da9040407d4a..74329e0953d1 100644
--- a/fs/crypto/fscrypt_private.h
+++ b/fs/crypto/fscrypt_private.h
@@ -395,7 +395,7 @@ void fscrypt_hkdf_expand(const struct hmac_sha512_key *hkdf, u8 context,
 			 const u8 *info, unsigned int infolen,
 			 u8 *okm, unsigned int okmlen);
 
-/* inline_crypt.c */
+/* block.c */
 #ifdef CONFIG_FS_ENCRYPTION_INLINE_CRYPT
 static inline bool
 fscrypt_using_inline_encryption(const struct fscrypt_inode_info *ci)
diff --git a/include/linux/fscrypt.h b/include/linux/fscrypt.h
index acf5b28eb9d7..52ff014aeae6 100644
--- a/include/linux/fscrypt.h
+++ b/include/linux/fscrypt.h
@@ -446,10 +446,6 @@ bool fscrypt_match_name(const struct fscrypt_name *fname,
 			const u8 *de_name, u32 de_name_len);
 u64 fscrypt_fname_siphash(const struct inode *dir, const struct qstr *name);
 
-/* bio.c */
-int fscrypt_zeroout_range(const struct inode *inode, loff_t pos,
-			  sector_t sector, u64 len);
-
 /* hooks.c */
 int fscrypt_file_open(struct inode *inode, struct file *filp);
 int __fscrypt_prepare_link(struct inode *inode, struct inode *dir,
@@ -737,14 +733,6 @@ static inline int fscrypt_d_revalidate(struct inode *dir, const struct qstr *nam
 	return 1;
 }
 
-/* bio.c */
-
-static inline int fscrypt_zeroout_range(const struct inode *inode, loff_t pos,
-					sector_t sector, u64 len)
-{
-	return -EOPNOTSUPP;
-}
-
 /* hooks.c */
 
 static inline int fscrypt_file_open(struct inode *inode, struct file *filp)
@@ -844,7 +832,7 @@ static inline void fscrypt_set_ops(struct super_block *sb,
 
 #endif	/* !CONFIG_FS_ENCRYPTION */
 
-/* inline_crypt.c */
+/* block.c */
 #ifdef CONFIG_FS_ENCRYPTION_INLINE_CRYPT
 
 void fscrypt_set_bio_crypt_ctx(struct bio *bio, const struct inode *inode,
@@ -854,6 +842,8 @@ bool fscrypt_mergeable_bio(struct bio *bio, const struct inode *inode,
 			   loff_t pos);
 
 u64 fscrypt_limit_io_blocks(const struct inode *inode, u64 lblk, u64 nr_blocks);
+int fscrypt_zeroout_range(const struct inode *inode, loff_t pos,
+			  sector_t sector, u64 len);
 
 #else /* CONFIG_FS_ENCRYPTION_INLINE_CRYPT */
 
@@ -873,6 +863,12 @@ static inline u64 fscrypt_limit_io_blocks(const struct inode *inode, u64 lblk,
 {
 	return nr_blocks;
 }
+
+static inline int fscrypt_zeroout_range(const struct inode *inode, loff_t pos,
+					sector_t sector, u64 len)
+{
+	return -EOPNOTSUPP;
+}
 #endif /* !CONFIG_FS_ENCRYPTION_INLINE_CRYPT */
 
 /**
-- 
2.54.0