Date:   Fri, 16 Dec 2016 11:50:06 +0100
From:   Richard Weinberger <richard@....at>
To:     linux-fsdevel@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org, jaegeuk@...nel.org, tytso@....edu,
        hch@...radead.org, arnd@...db.de, dedekind1@...il.com,
        linux-mtd@...ts.infradead.org, adrian.hunter@...el.com,
        linux-ext4@...r.kernel.org, ebiggers@...gle.com,
        rdunlap@...radead.org, david@...ma-star.at,
        Richard Weinberger <richard@....at>
Subject: [PATCH] fscrypt: Factor out bio specific functions

That way we can get rid of the direct dependency on CONFIG_BLOCK.

Reported-by: Arnd Bergmann <arnd@...db.de>
Reported-by: Randy Dunlap <rdunlap@...radead.org>
Suggested-by: Christoph Hellwig <hch@...radead.org>
Fixes: d475a507457b ("ubifs: Add skeleton for fscrypto")
Signed-off-by: Richard Weinberger <richard@....at>
---
 fs/crypto/Kconfig           |   1 -
 fs/crypto/Makefile          |   1 +
 fs/crypto/bio.c             | 115 ++++++++++++++++++++++++++++++++++++++++++++
 fs/crypto/crypto.c          |  89 ++--------------------------------
 fs/crypto/fscrypt_private.h |  14 ++++++
 include/linux/fscrypto.h    |   6 ++-
 6 files changed, 137 insertions(+), 89 deletions(-)
 create mode 100644 fs/crypto/bio.c

diff --git a/fs/crypto/Kconfig b/fs/crypto/Kconfig
index f514978f6688..08b46e6e3995 100644
--- a/fs/crypto/Kconfig
+++ b/fs/crypto/Kconfig
@@ -1,6 +1,5 @@
 config FS_ENCRYPTION
 	tristate "FS Encryption (Per-file encryption)"
-	depends on BLOCK
 	select CRYPTO
 	select CRYPTO_AES
 	select CRYPTO_CBC
diff --git a/fs/crypto/Makefile b/fs/crypto/Makefile
index f17684c48739..9f6607f17b53 100644
--- a/fs/crypto/Makefile
+++ b/fs/crypto/Makefile
@@ -1,3 +1,4 @@
 obj-$(CONFIG_FS_ENCRYPTION)	+= fscrypto.o
 
 fscrypto-y := crypto.o fname.o policy.o keyinfo.o
+fscrypto-$(CONFIG_BLOCK) += bio.o
diff --git a/fs/crypto/bio.c b/fs/crypto/bio.c
new file mode 100644
index 000000000000..6a6e694c6879
--- /dev/null
+++ b/fs/crypto/bio.c
@@ -0,0 +1,115 @@
+/*
+ * This contains encryption functions for per-file encryption.
+ *
+ * Copyright (C) 2015, Google, Inc.
+ * Copyright (C) 2015, Motorola Mobility
+ *
+ * Written by Michael Halcrow, 2014.
+ *
+ * Filename encryption additions
+ *	Uday Savagaonkar, 2014
+ * Encryption policy handling additions
+ *	Ildar Muslukhov, 2014
+ * Add fscrypt_pullback_bio_page()
+ *	Jaegeuk Kim, 2015.
+ *
+ * This has not yet undergone a rigorous security audit.
+ *
+ * The usage of AES-XTS should conform to recommendations in NIST
+ * Special Publication 800-38E and IEEE P1619/D16.
+ */
+
+#include <linux/pagemap.h>
+#include <linux/module.h>
+#include <linux/bio.h>
+#include <linux/namei.h>
+#include "fscrypt_private.h"
+
+/*
+ * Call fscrypt_decrypt_page on every single page, reusing the encryption
+ * context.
+ */
+static void completion_pages(struct work_struct *work)
+{
+	struct fscrypt_ctx *ctx =
+		container_of(work, struct fscrypt_ctx, r.work);
+	struct bio *bio = ctx->r.bio;
+	struct bio_vec *bv;
+	int i;
+
+	bio_for_each_segment_all(bv, bio, i) {
+		struct page *page = bv->bv_page;
+		int ret = fscrypt_decrypt_page(page->mapping->host, page,
+				PAGE_SIZE, 0, page->index);
+
+		if (ret) {
+			WARN_ON_ONCE(1);
+			SetPageError(page);
+		} else {
+			SetPageUptodate(page);
+		}
+		unlock_page(page);
+	}
+	fscrypt_release_ctx(ctx);
+	bio_put(bio);
+}
+
+void fscrypt_decrypt_bio_pages(struct fscrypt_ctx *ctx, struct bio *bio)
+{
+	INIT_WORK(&ctx->r.work, completion_pages);
+	ctx->r.bio = bio;
+	queue_work(fscrypt_read_workqueue, &ctx->r.work);
+}
+EXPORT_SYMBOL(fscrypt_decrypt_bio_pages);
+
+void fscrypt_pullback_bio_page(struct page **page, bool restore)
+{
+	struct fscrypt_ctx *ctx;
+	struct page *bounce_page;
+
+	/* The bounce data pages are unmapped. */
+	if ((*page)->mapping)
+		return;
+
+	/* The bounce data page is unmapped. */
+	bounce_page = *page;
+	ctx = (struct fscrypt_ctx *)page_private(bounce_page);
+
+	/* restore control page */
+	*page = ctx->w.control_page;
+
+	if (restore)
+		fscrypt_restore_control_page(bounce_page);
+}
+EXPORT_SYMBOL(fscrypt_pullback_bio_page);
+
+int fscrypt_bio_submit_page(const struct inode *inode, sector_t blk,
+			    struct page *page)
+{
+	struct bio *bio;
+	int ret;
+
+	bio = bio_alloc(GFP_NOWAIT, 1);
+	if (!bio) {
+		ret = -ENOMEM;
+		goto errout;
+	}
+	bio->bi_bdev = inode->i_sb->s_bdev;
+	bio->bi_iter.bi_sector = blk << (inode->i_sb->s_blocksize_bits - 9);
+	bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
+	ret = bio_add_page(bio, page, inode->i_sb->s_blocksize, 0);
+	if (ret != inode->i_sb->s_blocksize) {
+		/* should never happen! */
+		WARN_ON(1);
+		bio_put(bio);
+		ret = -EIO;
+		goto errout;
+	}
+	ret = submit_bio_wait(bio);
+	if ((ret == 0) && bio->bi_error)
+		ret = -EIO;
+	bio_put(bio);
+
+errout:
+	return ret;
+}
diff --git a/fs/crypto/crypto.c b/fs/crypto/crypto.c
index ac8e4f6a3773..3e981f0fd6e3 100644
--- a/fs/crypto/crypto.c
+++ b/fs/crypto/crypto.c
@@ -24,7 +24,6 @@
 #include <linux/module.h>
 #include <linux/scatterlist.h>
 #include <linux/ratelimit.h>
-#include <linux/bio.h>
 #include <linux/dcache.h>
 #include <linux/namei.h>
 #include "fscrypt_private.h"
@@ -44,7 +43,7 @@ static mempool_t *fscrypt_bounce_page_pool = NULL;
 static LIST_HEAD(fscrypt_free_ctxs);
 static DEFINE_SPINLOCK(fscrypt_ctx_lock);
 
-static struct workqueue_struct *fscrypt_read_workqueue;
+struct workqueue_struct *fscrypt_read_workqueue;
 static DEFINE_MUTEX(fscrypt_init_mutex);
 
 static struct kmem_cache *fscrypt_ctx_cachep;
@@ -330,8 +329,7 @@ int fscrypt_zeroout_range(const struct inode *inode, pgoff_t lblk,
 {
 	struct fscrypt_ctx *ctx;
 	struct page *ciphertext_page = NULL;
-	struct bio *bio;
-	int ret, err = 0;
+	int err = 0;
 
 	BUG_ON(inode->i_sb->s_blocksize != PAGE_SIZE);
 
@@ -349,33 +347,10 @@ int fscrypt_zeroout_range(const struct inode *inode, pgoff_t lblk,
 		err = do_page_crypto(inode, FS_ENCRYPT, lblk,
 					ZERO_PAGE(0), ciphertext_page,
 					PAGE_SIZE, 0, GFP_NOFS);
+		err = fscrypt_bio_submit_page(inode, pblk, ciphertext_page);
 		if (err)
 			goto errout;
 
-		bio = bio_alloc(GFP_NOWAIT, 1);
-		if (!bio) {
-			err = -ENOMEM;
-			goto errout;
-		}
-		bio->bi_bdev = inode->i_sb->s_bdev;
-		bio->bi_iter.bi_sector =
-			pblk << (inode->i_sb->s_blocksize_bits - 9);
-		bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
-		ret = bio_add_page(bio, ciphertext_page,
-					inode->i_sb->s_blocksize, 0);
-		if (ret != inode->i_sb->s_blocksize) {
-			/* should never happen! */
-			WARN_ON(1);
-			bio_put(bio);
-			err = -EIO;
-			goto errout;
-		}
-		err = submit_bio_wait(bio);
-		if ((err == 0) && bio->bi_error)
-			err = -EIO;
-		bio_put(bio);
-		if (err)
-			goto errout;
 		lblk++;
 		pblk++;
 	}
@@ -442,64 +417,6 @@ const struct dentry_operations fscrypt_d_ops = {
 };
 EXPORT_SYMBOL(fscrypt_d_ops);
 
-/*
- * Call fscrypt_decrypt_page on every single page, reusing the encryption
- * context.
- */
-static void completion_pages(struct work_struct *work)
-{
-	struct fscrypt_ctx *ctx =
-		container_of(work, struct fscrypt_ctx, r.work);
-	struct bio *bio = ctx->r.bio;
-	struct bio_vec *bv;
-	int i;
-
-	bio_for_each_segment_all(bv, bio, i) {
-		struct page *page = bv->bv_page;
-		int ret = fscrypt_decrypt_page(page->mapping->host, page,
-				PAGE_SIZE, 0, page->index);
-
-		if (ret) {
-			WARN_ON_ONCE(1);
-			SetPageError(page);
-		} else {
-			SetPageUptodate(page);
-		}
-		unlock_page(page);
-	}
-	fscrypt_release_ctx(ctx);
-	bio_put(bio);
-}
-
-void fscrypt_decrypt_bio_pages(struct fscrypt_ctx *ctx, struct bio *bio)
-{
-	INIT_WORK(&ctx->r.work, completion_pages);
-	ctx->r.bio = bio;
-	queue_work(fscrypt_read_workqueue, &ctx->r.work);
-}
-EXPORT_SYMBOL(fscrypt_decrypt_bio_pages);
-
-void fscrypt_pullback_bio_page(struct page **page, bool restore)
-{
-	struct fscrypt_ctx *ctx;
-	struct page *bounce_page;
-
-	/* The bounce data pages are unmapped. */
-	if ((*page)->mapping)
-		return;
-
-	/* The bounce data page is unmapped. */
-	bounce_page = *page;
-	ctx = (struct fscrypt_ctx *)page_private(bounce_page);
-
-	/* restore control page */
-	*page = ctx->w.control_page;
-
-	if (restore)
-		fscrypt_restore_control_page(bounce_page);
-}
-EXPORT_SYMBOL(fscrypt_pullback_bio_page);
-
 void fscrypt_restore_control_page(struct page *page)
 {
 	struct fscrypt_ctx *ctx;
diff --git a/fs/crypto/fscrypt_private.h b/fs/crypto/fscrypt_private.h
index aeab032d7d35..32a5b3598446 100644
--- a/fs/crypto/fscrypt_private.h
+++ b/fs/crypto/fscrypt_private.h
@@ -86,8 +86,22 @@ struct fscrypt_completion_result {
 
 /* crypto.c */
 int fscrypt_initialize(unsigned int cop_flags);
+extern struct workqueue_struct *fscrypt_read_workqueue;
 
 /* keyinfo.c */
 extern int fscrypt_get_crypt_info(struct inode *);
 
+/* bio.c */
+#ifdef CONFIG_BLOCK
+extern int fscrypt_bio_submit_page(const struct inode *inode, sector_t blk,
+				   struct page *page);
+#else
+static inline int fscrypt_bio_submit_page(const struct inode *inode,
+					  sector_t blk, struct page *page)
+{
+	WARN_ON_ONCE(1);
+	return -EINVAL;
+}
+#endif
+
 #endif /* _FSCRYPT_PRIVATE_H */
diff --git a/include/linux/fscrypto.h b/include/linux/fscrypto.h
index c074b670aa99..167b0dfd4e98 100644
--- a/include/linux/fscrypto.h
+++ b/include/linux/fscrypto.h
@@ -174,8 +174,6 @@ extern struct page *fscrypt_encrypt_page(const struct inode *, struct page *,
 						u64, gfp_t);
 extern int fscrypt_decrypt_page(const struct inode *, struct page *, unsigned int,
 				unsigned int, u64);
-extern void fscrypt_decrypt_bio_pages(struct fscrypt_ctx *, struct bio *);
-extern void fscrypt_pullback_bio_page(struct page **, bool);
 extern void fscrypt_restore_control_page(struct page *);
 extern int fscrypt_zeroout_range(const struct inode *, pgoff_t, sector_t,
 						unsigned int);
@@ -201,6 +199,10 @@ extern int fscrypt_fname_disk_to_usr(struct inode *, u32, u32,
 			const struct fscrypt_str *, struct fscrypt_str *);
 extern int fscrypt_fname_usr_to_disk(struct inode *, const struct qstr *,
 			struct fscrypt_str *);
+
+/* bio.c */
+extern void fscrypt_decrypt_bio_pages(struct fscrypt_ctx *, struct bio *);
+extern void fscrypt_pullback_bio_page(struct page **, bool);
 #endif
 
 /* crypto.c */
-- 
2.10.2

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