[v4,3/8] block: blk-crypto for Inline Encryption
diff mbox series

Message ID 20190821075714.65140-4-satyat@google.com
State Changes Requested
Headers show
Series
  • Inline Encryption Support
Related show

Commit Message

Satya Tangirala Aug. 21, 2019, 7:57 a.m. UTC
We introduce blk-crypto, which manages programming keyslots for struct
bios. With blk-crypto, filesystems only need to call bio_crypt_set_ctx with
the encryption key, algorithm and data_unit_num; they don't have to worry
about getting a keyslot for each encryption context, as blk-crypto handles
that. Blk-crypto also makes it possible for layered devices like device
mapper to make use of inline encryption hardware.

Blk-crypto delegates crypto operations to inline encryption hardware when
available, and also contains a software fallback to the kernel crypto API.
For more details, refer to Documentation/block/blk-crypto.txt.

Signed-off-by: Satya Tangirala <satyat@google.com>
---
 Documentation/block/inline-encryption.txt | 186 ++++++
 block/Kconfig                             |   2 +
 block/Makefile                            |   3 +-
 block/bio-crypt-ctx.c                     |   7 +-
 block/bio.c                               |   5 +
 block/blk-core.c                          |  11 +-
 block/blk-crypto.c                        | 737 ++++++++++++++++++++++
 include/linux/bio-crypt-ctx.h             |   7 +
 include/linux/blk-crypto.h                |  47 ++
 9 files changed, 1002 insertions(+), 3 deletions(-)
 create mode 100644 Documentation/block/inline-encryption.txt
 create mode 100644 block/blk-crypto.c
 create mode 100644 include/linux/blk-crypto.h

Comments

Jonathan Corbet Aug. 26, 2019, 6:17 p.m. UTC | #1
On Wed, 21 Aug 2019 00:57:09 -0700
Satya Tangirala <satyat@google.com> wrote:

> We introduce blk-crypto, which manages programming keyslots for struct
> bios. With blk-crypto, filesystems only need to call bio_crypt_set_ctx with
> the encryption key, algorithm and data_unit_num; they don't have to worry
> about getting a keyslot for each encryption context, as blk-crypto handles
> that. Blk-crypto also makes it possible for layered devices like device
> mapper to make use of inline encryption hardware.
> 
> Blk-crypto delegates crypto operations to inline encryption hardware when
> available, and also contains a software fallback to the kernel crypto API.
> For more details, refer to Documentation/block/blk-crypto.txt.

So that file doesn't seem to exist; did you mean inline-encryption.txt
here?

> Signed-off-by: Satya Tangirala <satyat@google.com>
> ---
>  Documentation/block/inline-encryption.txt | 186 ++++++
>  block/Kconfig                             |   2 +
>  block/Makefile                            |   3 +-
>  block/bio-crypt-ctx.c                     |   7 +-
>  block/bio.c                               |   5 +
>  block/blk-core.c                          |  11 +-
>  block/blk-crypto.c                        | 737 ++++++++++++++++++++++
>  include/linux/bio-crypt-ctx.h             |   7 +
>  include/linux/blk-crypto.h                |  47 ++
>  9 files changed, 1002 insertions(+), 3 deletions(-)
>  create mode 100644 Documentation/block/inline-encryption.txt
>  create mode 100644 block/blk-crypto.c
>  create mode 100644 include/linux/blk-crypto.h
> 
> diff --git a/Documentation/block/inline-encryption.txt b/Documentation/block/inline-encryption.txt
> new file mode 100644
> index 000000000000..925611a5ea65
> --- /dev/null
> +++ b/Documentation/block/inline-encryption.txt

So we've been doing our best to get rid of .txt files in the documentation
tree.  I'd really be a lot happier if this were an RST file instead.  The
good news is that it's already 99% RST, so little would have to change.

See the info in Documentation/doc-guide for details.

> @@ -0,0 +1,186 @@
> +BLK-CRYPTO and KEYSLOT MANAGER
> +===========================
> +
> +CONTENTS
> +1. Objective
> +2. Constraints and notes
> +3. Design
> +4. Blk-crypto
> + 4-1 What does blk-crypto do on bio submission
> +5. Layered Devices
> +6. Future optimizations for layered devices

RST would generate this TOC for you, so you can take it out.

> +1. Objective
> +============
> +
> +We want to support inline encryption (IE) in the kernel.
> +To allow for testing, we also want a crypto API fallback when actual
> +IE hardware is absent. We also want IE to work with layered devices
> +like dm and loopback (i.e. we want to be able to use the IE hardware
> +of the underlying devices if present, or else fall back to crypto API
> +en/decryption).
> +
> +
> +2. Constraints and notes
> +========================
> +
> +1) IE hardware have a limited number of “keyslots” that can be programmed

Some people get irate when they encounter non-ASCII characters in the docs;
that includes "smart quotes".

Also, s/have/has/

> +with an encryption context (key, algorithm, data unit size, etc.) at any time.
> +One can specify a keyslot in a data request made to the device, and the
> +device will en/decrypt the data using the encryption context programmed into
> +that specified keyslot. When possible, we want to make multiple requests with
> +the same encryption context share the same keyslot.
> +
> +2) We need a way for filesystems to specify an encryption context to use for
> +en/decrypting a struct bio, and a device driver (like UFS) needs to be able
> +to use that encryption context when it processes the bio.
> +
> +3) We need a way for device drivers to expose their capabilities in a unified
> +way to the upper layers.
> +
> +
> +3. Design
> +=========
> +
> +We add a struct bio_crypt_ctx to struct bio that can represent an
> +encryption context, because we need to be able to pass this encryption
> +context from the FS layer to the device driver to act upon.
> +
> +While IE hardware works on the notion of keyslots, the FS layer has no
> +knowledge of keyslots - it simply wants to specify an encryption context to
> +use while en/decrypting a bio.
> +
> +We introduce a keyslot manager (KSM) that handles the translation from
> +encryption contexts specified by the FS to keyslots on the IE hardware.

So...if this were RST, you could have directives to pull in the nice
kerneldoc comments you've already put into the source.

I'll stop here...presumably I've made my point by now :)

Thanks for documenting this subsystem!

jon
Eric Biggers Aug. 27, 2019, 10:34 p.m. UTC | #2
On Wed, Aug 21, 2019 at 12:57:09AM -0700, Satya Tangirala wrote:
> diff --git a/block/blk-crypto.c b/block/blk-crypto.c
> new file mode 100644
> index 000000000000..c8f06264a0f5
> --- /dev/null
> +++ b/block/blk-crypto.c
> @@ -0,0 +1,737 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright 2019 Google LLC
> + */
> +
> +/*
> + * Refer to Documentation/block/inline-encryption.txt for detailed explanation.
> + */
> +
> +#ifdef pr_fmt
> +#undef pr_fmt
> +#endif

This is the beginning of the file, so the

#ifdef pr_fmt
#undef pr_fmt
#endif

is unnecessary.

> +static struct blk_crypto_keyslot {
> +	struct crypto_skcipher *tfm;
> +	enum blk_crypto_mode_num crypto_mode;
> +	u8 key[BLK_CRYPTO_MAX_KEY_SIZE];
> +	struct crypto_skcipher *tfms[ARRAY_SIZE(blk_crypto_modes)];
> +} *blk_crypto_keyslots;

It would be helpful if there was a comment somewhere explaining what's going on
with the crypto tfms now, like:

/*
 * Allocating a crypto tfm during I/O can deadlock, so we have to preallocate
 * all a mode's tfms when that mode starts being used.  Since each mode may need
 * all the keyslots at some point, each mode needs its own tfm for each keyslot;
 * thus, a keyslot may contain tfms for multiple modes.  However, to match the
 * behavior of real inline encryption hardware (which only supports a single
 * encryption context per keyslot), we only allow one tfm per keyslot to be used
 * at a time.  Unused tfms have their keys cleared.
 */

Otherwise it's not at all obvious what's going on.

> +
> +static struct mutex tfms_lock[ARRAY_SIZE(blk_crypto_modes)];
> +static bool tfms_inited[ARRAY_SIZE(blk_crypto_modes)];
> +
> +struct work_mem {
> +	struct work_struct crypto_work;
> +	struct bio *bio;
> +};
> +
> +/* The following few vars are only used during the crypto API fallback */
> +static struct keyslot_manager *blk_crypto_ksm;
> +static struct workqueue_struct *blk_crypto_wq;
> +static mempool_t *blk_crypto_page_pool;
> +static struct kmem_cache *blk_crypto_work_mem_cache;
> +
> +bool bio_crypt_swhandled(struct bio *bio)
> +{
> +	return bio_has_crypt_ctx(bio) &&
> +	       bio->bi_crypt_context->processing_ksm == blk_crypto_ksm;
> +}
> +
> +static const u8 zeroes[BLK_CRYPTO_MAX_KEY_SIZE];
> +static void evict_keyslot(unsigned int slot)
> +{
> +	struct blk_crypto_keyslot *slotp = &blk_crypto_keyslots[slot];
> +	enum blk_crypto_mode_num crypto_mode = slotp->crypto_mode;
> +
> +	/* Clear the key in the skcipher */
> +	crypto_skcipher_setkey(slotp->tfms[crypto_mode], zeroes,
> +			       blk_crypto_modes[crypto_mode].keysize);
> +	memzero_explicit(slotp->key, BLK_CRYPTO_MAX_KEY_SIZE);
> +}

Unfortunately setting the all-zeroes key won't work, because the all-zeroes key
fails the "weak key" check for XTS, as its two halves are the same.

Presumably this wasn't noticed during testing because the return value of
crypto_skcipher_setkey() is ignored.  So I suggest adding a WARN_ON():

	err = crypto_skcipher_setkey(slotp->tfms[crypto_mode], blank_key,
				     blk_crypto_modes[crypto_mode].keysize);
	WARN_ON(err);

Then for the actual fix, maybe set a random key instead of an all-zeroes one?

> +
> +static int blk_crypto_keyslot_program(void *priv, const u8 *key,
> +				      enum blk_crypto_mode_num crypto_mode,
> +				      unsigned int data_unit_size,
> +				      unsigned int slot)
> +{
> +	struct blk_crypto_keyslot *slotp = &blk_crypto_keyslots[slot];
> +	const struct blk_crypto_mode *mode = &blk_crypto_modes[crypto_mode];
> +	size_t keysize = mode->keysize;
> +	int err;
> +
> +	if (crypto_mode != slotp->crypto_mode) {
> +		evict_keyslot(slot);
> +		slotp->crypto_mode = crypto_mode;
> +	}

Currently the crypto_mode of every blk_crypto_keyslot starts out as AES_256_XTS
(0).  So if the user starts by choosing some other mode, this will immediately
call evict_keyslot() and crash dereferencing a NULL pointer.

To fix this, how about initializing all the modes to
BLK_ENCRYPTION_MODE_INVALID?

Then here the code would need to be:

	if (crypto_mode != slotp->crypto_mode &&
	    slotp->crypto_mode != BLK_ENCRYPTION_MODE_INVALID)
		evict_keyslot(slot);

And evict_keyslot() should invalidate the crypto_mode:

static void evict_keyslot(unsigned int slot)
{
	...

	slotp->crypto_mode = BLK_ENCRYPTION_MODE_INVALID;
}

> +
> +static int blk_crypto_keyslot_evict(void *priv, const u8 *key,
> +				    enum blk_crypto_mode_num crypto_mode,
> +				    unsigned int data_unit_size,
> +				    unsigned int slot)
> +{
> +	evict_keyslot(slot);
> +	return 0;
> +}

It might be useful to have a WARN_ON() here if the keyslot isn't in use
(i.e., if slotp->crypto_mode == BLK_ENCRYPTION_MODE_INVALID).

> +int blk_crypto_submit_bio(struct bio **bio_ptr)
> +{
> +	struct bio *bio = *bio_ptr;
> +	struct request_queue *q;
> +	int err;
> +	struct bio_crypt_ctx *crypt_ctx;
> +
> +	if (!bio_has_crypt_ctx(bio) || !bio_has_data(bio))
> +		return 0;
> +
> +	/*
> +	 * When a read bio is marked for sw decryption, its bi_iter is saved
> +	 * so that when we decrypt the bio later, we know what part of it was
> +	 * marked for sw decryption (when the bio is passed down after
> +	 * blk_crypto_submit bio, it may be split or advanced so we cannot rely
> +	 * on the bi_iter while decrypting in blk_crypto_endio)
> +	 */
> +	if (bio_crypt_swhandled(bio))
> +		return 0;
> +
> +	err = bio_crypt_check_alignment(bio);
> +	if (err)
> +		goto out;

Need to set ->bi_status if bio_crypt_check_alignment() fails.

> +bool blk_crypto_endio(struct bio *bio)
> +{
> +	if (!bio_has_crypt_ctx(bio))
> +		return true;
> +
> +	if (bio_crypt_swhandled(bio)) {
> +		/*
> +		 * The only bios that are swhandled when they reach here
> +		 * are those with bio_data_dir(bio) == READ, since WRITE
> +		 * bios that are encrypted by the crypto API fallback are
> +		 * handled by blk_crypto_encrypt_endio.
> +		 */
> +
> +		/* If there was an IO error, don't decrypt. */
> +		if (bio->bi_status)
> +			return true;
> +
> +		blk_crypto_queue_decrypt_bio(bio);
> +		return false;
> +	}
> +
> +	if (bio_has_crypt_ctx(bio) && bio_crypt_has_keyslot(bio))
> +		bio_crypt_ctx_release_keyslot(bio);

No need to check bio_has_crypt_ctx(bio) here, as it was already checked above.

> +int blk_crypto_mode_alloc_ciphers(enum blk_crypto_mode_num mode_num)
> +{
> +	struct blk_crypto_keyslot *slotp;
> +	int err = 0;
> +	int i;
> +
> +	/* Fast path */
> +	if (likely(READ_ONCE(tfms_inited[mode_num]))) {
> +		/*
> +		 * Ensure that updates to blk_crypto_keyslots[i].tfms[mode_num]
> +		 * for each i are visible before we try to access them.
> +		 */
> +		smp_rmb();
> +		return 0;
> +	}

I think we want smp_load_acquire() here.

	/* pairs with smp_store_release() below */
	if (smp_load_acquire(&tfms_inited[mode_num]))
		return 0;

> +
> +	mutex_lock(&tfms_lock[mode_num]);
> +	if (likely(tfms_inited[mode_num]))
> +		goto out;
> +
> +	for (i = 0; i < blk_crypto_num_keyslots; i++) {
> +		slotp = &blk_crypto_keyslots[i];
> +		slotp->tfms[mode_num] = crypto_alloc_skcipher(
> +					blk_crypto_modes[mode_num].cipher_str,
> +					0, 0);
> +		if (IS_ERR(slotp->tfms[mode_num])) {
> +			err = PTR_ERR(slotp->tfms[mode_num]);
> +			slotp->tfms[mode_num] = NULL;
> +			goto out_free_tfms;
> +		}
> +
> +		crypto_skcipher_set_flags(slotp->tfms[mode_num],
> +					  CRYPTO_TFM_REQ_FORBID_WEAK_KEYS);
> +	}
> +
> +	/*
> +	 * Ensure that updates to blk_crypto_keyslots[i].tfms[mode_num]
> +	 * for each i are visible before we set tfms_inited[mode_num].
> +	 */
> +	smp_wmb();
> +	WRITE_ONCE(tfms_inited[mode_num], true);
> +	goto out;

... and smp_store_release() here.

	/* pairs with smp_load_acquire() above */
	smp_store_release(&tfms_inited[mode_num], true);
	goto out;

- Eric

Patch
diff mbox series

diff --git a/Documentation/block/inline-encryption.txt b/Documentation/block/inline-encryption.txt
new file mode 100644
index 000000000000..925611a5ea65
--- /dev/null
+++ b/Documentation/block/inline-encryption.txt
@@ -0,0 +1,186 @@ 
+BLK-CRYPTO and KEYSLOT MANAGER
+===========================
+
+CONTENTS
+1. Objective
+2. Constraints and notes
+3. Design
+4. Blk-crypto
+ 4-1 What does blk-crypto do on bio submission
+5. Layered Devices
+6. Future optimizations for layered devices
+
+1. Objective
+============
+
+We want to support inline encryption (IE) in the kernel.
+To allow for testing, we also want a crypto API fallback when actual
+IE hardware is absent. We also want IE to work with layered devices
+like dm and loopback (i.e. we want to be able to use the IE hardware
+of the underlying devices if present, or else fall back to crypto API
+en/decryption).
+
+
+2. Constraints and notes
+========================
+
+1) IE hardware have a limited number of “keyslots” that can be programmed
+with an encryption context (key, algorithm, data unit size, etc.) at any time.
+One can specify a keyslot in a data request made to the device, and the
+device will en/decrypt the data using the encryption context programmed into
+that specified keyslot. When possible, we want to make multiple requests with
+the same encryption context share the same keyslot.
+
+2) We need a way for filesystems to specify an encryption context to use for
+en/decrypting a struct bio, and a device driver (like UFS) needs to be able
+to use that encryption context when it processes the bio.
+
+3) We need a way for device drivers to expose their capabilities in a unified
+way to the upper layers.
+
+
+3. Design
+=========
+
+We add a struct bio_crypt_ctx to struct bio that can represent an
+encryption context, because we need to be able to pass this encryption
+context from the FS layer to the device driver to act upon.
+
+While IE hardware works on the notion of keyslots, the FS layer has no
+knowledge of keyslots - it simply wants to specify an encryption context to
+use while en/decrypting a bio.
+
+We introduce a keyslot manager (KSM) that handles the translation from
+encryption contexts specified by the FS to keyslots on the IE hardware.
+This KSM also serves as the way IE hardware can expose their capabilities to
+upper layers. The generic mode of operation is: each device driver that wants
+to support IE will construct a KSM and set it up in its struct request_queue.
+Upper layers that want to use IE on this device can then use this KSM in
+the device’s struct request_queue to translate an encryption context into
+a keyslot. The presence of the KSM in the request queue shall be used to mean
+that the device supports IE.
+
+On the device driver end of the interface, the device driver needs to tell the
+KSM how to actually manipulate the IE hardware in the device to do things like
+programming the crypto key into the IE hardware into a particular keyslot. All
+this is achieved through the struct keyslot_mgmt_ll_ops that the device driver
+passes to the KSM when creating it.
+
+It uses refcounts to track which keyslots are idle (either they have no
+encryption context programmed, or there are no in-flight struct bios
+referencing that keyslot). When a new encryption context needs a keyslot, it
+tries to find a keyslot that has already been programmed with the same
+encryption context, and if there is no such keyslot, it evicts the least
+recently used idle keyslot and programs the new encryption context into that
+one. If no idle keyslots are available, then the caller will sleep until there
+is at least one.
+
+
+4. Blk-crypto
+=============
+
+The above is sufficient for simple cases, but does not work if there is a
+need for a crypto API fallback, or if we are want to use IE with layered
+devices. To these ends, we introduce blk-crypto. Blk-crypto allows us to
+present a unified view of encryption to the FS (so FS only needs to specify
+an encryption context and not worry about keyslots at all), and blk-crypto
+can decide whether to delegate the en/decryption to IE hardware or to the
+crypto API. Blk-crypto maintains an internal KSM that serves as the crypto
+API fallback.
+
+Blk-crypto needs to ensure that the encryption context is programmed into the
+"correct" keyslot manager for IE. If a bio is submitted to a layered device
+that eventually passes the bio down to a device that really does support IE, we
+want the encryption context to be programmed into a keyslot for the KSM of the
+device with IE support. However, blk-crypto does not know a priori whether a
+particular device is the final device in the layering structure for a bio or
+not. So in the case that a particular device does not support IE, since it is
+possibly the final destination device for the bio, if the bio requires
+encryption (i.e. the bio is doing a write operation), blk-crypto must fallback
+to the crypto API *before* sending the bio to the device.
+
+Blk-crypto ensures that
+1) The bio’s encryption context is programmed into a keyslot in the KSM of the
+request queue that the bio is being submitted to (or the crypto API fallback KSM
+if the request queue doesn’t have a KSM), and that the processing_ksm in the
+bi_crypt_context is set to this KSM
+
+2) That the bio has its own individual reference to the keyslot in this KSM.
+Once the bio passes through blk-crypto, its encryption context is programmed
+in some KSM. The “its own individual reference to the keyslot” ensures that
+keyslots can be released by each bio independently of other bios while ensuring
+that the bio has a valid reference to the keyslot when, for e.g., the crypto API
+fallback KSM in blk-crypto performs crypto on the device’s behalf. The individual
+references are ensured by increasing the refcount for the keyslot in the
+processing_ksm when a bio with a programmed encryption context is cloned.
+
+
+4-1. What blk-crypto does on bio submission
+-------------------------------------------
+
+Case 1: blk-crypto is given a bio with only an encryption context that hasn’t
+been programmed into any keyslot in any KSM (for e.g. a bio from the FS). In
+this case, blk-crypto will program the encryption context into the KSM of the
+request queue the bio is being submitted to (and if this KSM does not exist,
+then it will program it into blk-crypto’s internal KSM for crypto API fallback).
+The KSM that this encryption context was programmed into is stored as the
+processing_ksm in the bio’s bi_crypt_context.
+
+Case 2: blk-crypto is given a bio whose encryption context has already been
+programmed into a keyslot in the *crypto API fallback KSM*. In this case,
+blk-crypto does nothing; it treats the bio as not having specified an
+encryption context. Note that we cannot do here what we will do in Case 3
+because we would have already encrypted the bio via the crypto API by this
+point.
+
+Case 3: blk-crypto is given a bio whose encryption context has already been
+programmed into a keyslot in some KSM (that is *not* the crypto API fallback
+KSM). In this case, blk-crypto first releases that keyslot from that KSM and
+then treats the bio as in Case 1.
+
+This way, when a device driver is processing a bio, it can be sure that
+the bio’s encryption context has been programmed into some KSM (either the
+device driver’s request queue’s KSM, or blk-crypto’s crypto API fallback KSM).
+It then simply needs to check if the bio’s processing_ksm is the device’s
+request queue’s KSM. If so, then it should proceed with IE. If not, it should
+simply do nothing with respect to crypto, because some other KSM (perhaps the
+blk-crypto crypto API fallback KSM) is handling the en/decryption.
+
+Blk-crypto will release the keyslot that is being held by the bio (and also
+decrypt it if the bio is using the crypto API fallback KSM) once
+bio_remaining_done returns true for the bio.
+
+
+5. Layered Devices
+==================
+
+Layered devices that wish to support IE need to create their own keyslot
+manager for their request queue, and expose whatever functionality they choose.
+When a layered device wants to pass a bio to another layer (either by
+resubmitting the same bio, or by submitting a clone), it doesn’t need to do
+anything special because the bio (or the clone) will once again pass through
+blk-crypto, which will work as described in Case 3. If a layered device wants
+for some reason to do the IO by itself instead of passing it on to a child
+device, but it also chose to expose IE capabilities by setting up a KSM in its
+request queue, it is then responsible for en/decrypting the data itself. In
+such cases, the device can choose to call the blk-crypto function
+blk_crypto_fallback_to_kernel_crypto_api (TODO: Not yet implemented), which will
+cause the en/decryption to be done via the crypto API fallback.
+
+
+6. Future Optimizations for layered devices
+===========================================
+
+Creating a keyslot manager for the layered device uses up memory for each
+keyslot, and in general, a layered device (like dm-linear) merely passes the
+request on to a “child” device, so the keyslots in the layered device itself
+might be completely unused. We can instead define a new type of KSM; the
+“passthrough KSM”, that layered devices can use to let blk-crypto know that
+this layered device *will* pass the bio to some child device (and hence
+through blk-crypto again, at which point blk-crypto can program the encryption
+context, instead of programming it into the layered device’s KSM). Again, if
+the device “lies” and decides to do the IO itself instead of passing it on to
+a child device, it is responsible for doing the en/decryption (and can choose
+to call blk_crypto_fallback_to_kernel_crypto_api). Another use case for the
+"passthrough KSM" is for IE devices that want to manage their own keyslots/do
+not have a limited number of keyslots.
diff --git a/block/Kconfig b/block/Kconfig
index 1469efdd385b..4f7e593d0a6d 100644
--- a/block/Kconfig
+++ b/block/Kconfig
@@ -166,6 +166,8 @@  config BLK_SED_OPAL
 
 config BLK_INLINE_ENCRYPTION
 	bool "Enable inline encryption support in block layer"
+	select CRYPTO
+	select CRYPTO_BLKCIPHER
 	help
 	  Build the blk-crypto subsystem.
 	  Enabling this lets the block layer handle encryption,
diff --git a/block/Makefile b/block/Makefile
index 4147ffa63631..1ba7de84dbaf 100644
--- a/block/Makefile
+++ b/block/Makefile
@@ -35,4 +35,5 @@  obj-$(CONFIG_BLK_DEBUG_FS)	+= blk-mq-debugfs.o
 obj-$(CONFIG_BLK_DEBUG_FS_ZONED)+= blk-mq-debugfs-zoned.o
 obj-$(CONFIG_BLK_SED_OPAL)	+= sed-opal.o
 obj-$(CONFIG_BLK_PM)		+= blk-pm.o
-obj-$(CONFIG_BLK_INLINE_ENCRYPTION)	+= keyslot-manager.o bio-crypt-ctx.o
+obj-$(CONFIG_BLK_INLINE_ENCRYPTION)	+= keyslot-manager.o bio-crypt-ctx.o \
+					   blk-crypto.o
diff --git a/block/bio-crypt-ctx.c b/block/bio-crypt-ctx.c
index aa3571f72ee7..6a2b061865c6 100644
--- a/block/bio-crypt-ctx.c
+++ b/block/bio-crypt-ctx.c
@@ -43,7 +43,12 @@  EXPORT_SYMBOL(bio_crypt_free_ctx);
 
 int bio_crypt_clone(struct bio *dst, struct bio *src, gfp_t gfp_mask)
 {
-	if (!bio_has_crypt_ctx(src))
+	/*
+	 * If a bio is swhandled, then it will be decrypted when bio_endio
+	 * is called. As we only want the data to be decrypted once, copies
+	 * of the bio must not have have a crypt context.
+	 */
+	if (!bio_has_crypt_ctx(src) || bio_crypt_swhandled(src))
 		return 0;
 
 	dst->bi_crypt_context = bio_crypt_alloc_ctx(gfp_mask);
diff --git a/block/bio.c b/block/bio.c
index ada9850c90dc..e2537e5588ac 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -17,6 +17,7 @@ 
 #include <linux/cgroup.h>
 #include <linux/blk-cgroup.h>
 #include <linux/highmem.h>
+#include <linux/blk-crypto.h>
 
 #include <trace/events/block.h>
 #include "blk.h"
@@ -1800,6 +1801,10 @@  void bio_endio(struct bio *bio)
 again:
 	if (!bio_remaining_done(bio))
 		return;
+
+	if (!blk_crypto_endio(bio))
+		return;
+
 	if (!bio_integrity_endio(bio))
 		return;
 
diff --git a/block/blk-core.c b/block/blk-core.c
index 35027e80e27d..f699ecd9ca2e 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -36,6 +36,7 @@ 
 #include <linux/blk-cgroup.h>
 #include <linux/debugfs.h>
 #include <linux/bpf.h>
+#include <linux/blk-crypto.h>
 
 #define CREATE_TRACE_POINTS
 #include <trace/events/block.h>
@@ -1049,7 +1050,9 @@  blk_qc_t generic_make_request(struct bio *bio)
 			/* Create a fresh bio_list for all subordinate requests */
 			bio_list_on_stack[1] = bio_list_on_stack[0];
 			bio_list_init(&bio_list_on_stack[0]);
-			ret = q->make_request_fn(q, bio);
+
+			if (!blk_crypto_submit_bio(&bio))
+				ret = q->make_request_fn(q, bio);
 
 			blk_queue_exit(q);
 
@@ -1102,6 +1105,9 @@  blk_qc_t direct_make_request(struct bio *bio)
 	if (!generic_make_request_checks(bio))
 		return BLK_QC_T_NONE;
 
+	if (blk_crypto_submit_bio(&bio))
+		return BLK_QC_T_NONE;
+
 	if (unlikely(blk_queue_enter(q, nowait ? BLK_MQ_REQ_NOWAIT : 0))) {
 		if (nowait && !blk_queue_dying(q))
 			bio->bi_status = BLK_STS_AGAIN;
@@ -1772,5 +1778,8 @@  int __init blk_dev_init(void)
 	if (bio_crypt_ctx_init() < 0)
 		panic("Failed to allocate mem for bio crypt ctxs\n");
 
+	if (blk_crypto_init() < 0)
+		panic("Failed to init blk-crypto\n");
+
 	return 0;
 }
diff --git a/block/blk-crypto.c b/block/blk-crypto.c
new file mode 100644
index 000000000000..c8f06264a0f5
--- /dev/null
+++ b/block/blk-crypto.c
@@ -0,0 +1,737 @@ 
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright 2019 Google LLC
+ */
+
+/*
+ * Refer to Documentation/block/inline-encryption.txt for detailed explanation.
+ */
+
+#ifdef pr_fmt
+#undef pr_fmt
+#endif
+
+#define pr_fmt(fmt) "blk-crypto: " fmt
+
+#include <linux/blk-crypto.h>
+#include <linux/keyslot-manager.h>
+#include <linux/mempool.h>
+#include <linux/blk-cgroup.h>
+#include <linux/crypto.h>
+#include <crypto/skcipher.h>
+#include <crypto/algapi.h>
+#include <linux/module.h>
+#include <linux/sched/mm.h>
+
+/* Represents a crypto mode supported by blk-crypto  */
+struct blk_crypto_mode {
+	const char *cipher_str; /* crypto API name (for fallback case) */
+	size_t keysize; /* key size in bytes */
+};
+
+static const struct blk_crypto_mode blk_crypto_modes[] = {
+	[BLK_ENCRYPTION_MODE_AES_256_XTS] = {
+		.cipher_str = "xts(aes)",
+		.keysize = 64,
+	},
+};
+
+static unsigned int num_prealloc_bounce_pg = 32;
+module_param(num_prealloc_bounce_pg, uint, 0);
+MODULE_PARM_DESC(num_prealloc_bounce_pg,
+	"Number of preallocated bounce pages for blk-crypto to use during crypto API fallback encryption");
+
+#define BLK_CRYPTO_MAX_KEY_SIZE 64
+static int blk_crypto_num_keyslots = 100;
+module_param_named(num_keyslots, blk_crypto_num_keyslots, int, 0);
+MODULE_PARM_DESC(num_keyslots,
+		 "Number of keyslots for crypto API fallback in blk-crypto.");
+
+static struct blk_crypto_keyslot {
+	struct crypto_skcipher *tfm;
+	enum blk_crypto_mode_num crypto_mode;
+	u8 key[BLK_CRYPTO_MAX_KEY_SIZE];
+	struct crypto_skcipher *tfms[ARRAY_SIZE(blk_crypto_modes)];
+} *blk_crypto_keyslots;
+
+static struct mutex tfms_lock[ARRAY_SIZE(blk_crypto_modes)];
+static bool tfms_inited[ARRAY_SIZE(blk_crypto_modes)];
+
+struct work_mem {
+	struct work_struct crypto_work;
+	struct bio *bio;
+};
+
+/* The following few vars are only used during the crypto API fallback */
+static struct keyslot_manager *blk_crypto_ksm;
+static struct workqueue_struct *blk_crypto_wq;
+static mempool_t *blk_crypto_page_pool;
+static struct kmem_cache *blk_crypto_work_mem_cache;
+
+bool bio_crypt_swhandled(struct bio *bio)
+{
+	return bio_has_crypt_ctx(bio) &&
+	       bio->bi_crypt_context->processing_ksm == blk_crypto_ksm;
+}
+
+static const u8 zeroes[BLK_CRYPTO_MAX_KEY_SIZE];
+static void evict_keyslot(unsigned int slot)
+{
+	struct blk_crypto_keyslot *slotp = &blk_crypto_keyslots[slot];
+	enum blk_crypto_mode_num crypto_mode = slotp->crypto_mode;
+
+	/* Clear the key in the skcipher */
+	crypto_skcipher_setkey(slotp->tfms[crypto_mode], zeroes,
+			       blk_crypto_modes[crypto_mode].keysize);
+	memzero_explicit(slotp->key, BLK_CRYPTO_MAX_KEY_SIZE);
+}
+
+static int blk_crypto_keyslot_program(void *priv, const u8 *key,
+				      enum blk_crypto_mode_num crypto_mode,
+				      unsigned int data_unit_size,
+				      unsigned int slot)
+{
+	struct blk_crypto_keyslot *slotp = &blk_crypto_keyslots[slot];
+	const struct blk_crypto_mode *mode = &blk_crypto_modes[crypto_mode];
+	size_t keysize = mode->keysize;
+	int err;
+
+	if (crypto_mode != slotp->crypto_mode) {
+		evict_keyslot(slot);
+		slotp->crypto_mode = crypto_mode;
+	}
+
+	if (!slotp->tfms[crypto_mode])
+		return -ENOMEM;
+	err = crypto_skcipher_setkey(slotp->tfms[crypto_mode], key, keysize);
+
+	if (err) {
+		evict_keyslot(slot);
+		return err;
+	}
+
+	memcpy(slotp->key, key, keysize);
+
+	return 0;
+}
+
+static int blk_crypto_keyslot_evict(void *priv, const u8 *key,
+				    enum blk_crypto_mode_num crypto_mode,
+				    unsigned int data_unit_size,
+				    unsigned int slot)
+{
+	evict_keyslot(slot);
+	return 0;
+}
+
+static int blk_crypto_keyslot_find(void *priv,
+				   const u8 *key,
+				   enum blk_crypto_mode_num crypto_mode,
+				   unsigned int data_unit_size_bytes)
+{
+	int slot;
+	const size_t keysize = blk_crypto_modes[crypto_mode].keysize;
+
+	for (slot = 0; slot < blk_crypto_num_keyslots; slot++) {
+		if (blk_crypto_keyslots[slot].crypto_mode == crypto_mode &&
+		    !crypto_memneq(blk_crypto_keyslots[slot].key, key, keysize))
+			return slot;
+	}
+
+	return -ENOKEY;
+}
+
+static bool blk_crypto_mode_supported(void *priv,
+				      enum blk_crypto_mode_num crypt_mode,
+				      unsigned int data_unit_size)
+{
+	/* All blk_crypto_modes are required to have a crypto API fallback. */
+	return true;
+}
+
+/*
+ * The crypto API fallback KSM ops - only used for a bio when it specifies a
+ * blk_crypto_mode for which we failed to get a keyslot in the device's inline
+ * encryption hardware (which probably means the device doesn't have inline
+ * encryption hardware that supports that crypto mode).
+ */
+static const struct keyslot_mgmt_ll_ops blk_crypto_ksm_ll_ops = {
+	.keyslot_program	= blk_crypto_keyslot_program,
+	.keyslot_evict		= blk_crypto_keyslot_evict,
+	.keyslot_find		= blk_crypto_keyslot_find,
+	.crypto_mode_supported	= blk_crypto_mode_supported,
+};
+
+static void blk_crypto_encrypt_endio(struct bio *enc_bio)
+{
+	struct bio *src_bio = enc_bio->bi_private;
+	int i;
+
+	for (i = 0; i < enc_bio->bi_vcnt; i++)
+		mempool_free(enc_bio->bi_io_vec[i].bv_page,
+			     blk_crypto_page_pool);
+
+	src_bio->bi_status = enc_bio->bi_status;
+
+	bio_put(enc_bio);
+	bio_endio(src_bio);
+}
+
+static struct bio *blk_crypto_clone_bio(struct bio *bio_src)
+{
+	struct bvec_iter iter;
+	struct bio_vec bv;
+	struct bio *bio;
+
+	bio = bio_alloc_bioset(GFP_NOIO, bio_segments(bio_src), NULL);
+	if (!bio)
+		return NULL;
+	bio->bi_disk		= bio_src->bi_disk;
+	bio->bi_opf		= bio_src->bi_opf;
+	bio->bi_ioprio		= bio_src->bi_ioprio;
+	bio->bi_write_hint	= bio_src->bi_write_hint;
+	bio->bi_iter.bi_sector	= bio_src->bi_iter.bi_sector;
+	bio->bi_iter.bi_size	= bio_src->bi_iter.bi_size;
+
+	bio_for_each_segment(bv, bio_src, iter)
+		bio->bi_io_vec[bio->bi_vcnt++] = bv;
+
+	if (bio_integrity(bio_src) &&
+	    bio_integrity_clone(bio, bio_src, GFP_NOIO) < 0) {
+		bio_put(bio);
+		return NULL;
+	}
+
+	bio_clone_blkg_association(bio, bio_src);
+	blkcg_bio_issue_init(bio);
+
+	return bio;
+}
+
+/* Check that all I/O segments are data unit aligned */
+static int bio_crypt_check_alignment(struct bio *bio)
+{
+	int data_unit_size = 1 << bio->bi_crypt_context->data_unit_size_bits;
+	struct bvec_iter iter;
+	struct bio_vec bv;
+
+	bio_for_each_segment(bv, bio, iter) {
+		if (!IS_ALIGNED(bv.bv_len | bv.bv_offset, data_unit_size))
+			return -EIO;
+	}
+	return 0;
+}
+
+static int blk_crypto_alloc_cipher_req(struct bio *src_bio,
+				       struct skcipher_request **ciph_req_ptr,
+				       struct crypto_wait *wait)
+{
+	int slot;
+	struct skcipher_request *ciph_req;
+	struct blk_crypto_keyslot *slotp;
+
+	slot = bio_crypt_get_keyslot(src_bio);
+	slotp = &blk_crypto_keyslots[slot];
+	ciph_req = skcipher_request_alloc(slotp->tfms[slotp->crypto_mode],
+					  GFP_NOIO);
+	if (!ciph_req) {
+		src_bio->bi_status = BLK_STS_RESOURCE;
+		return -ENOMEM;
+	}
+
+	skcipher_request_set_callback(ciph_req,
+				      CRYPTO_TFM_REQ_MAY_BACKLOG |
+				      CRYPTO_TFM_REQ_MAY_SLEEP,
+				      crypto_req_done, wait);
+	*ciph_req_ptr = ciph_req;
+	return 0;
+}
+
+static int blk_crypto_split_bio_if_needed(struct bio **bio_ptr)
+{
+	struct bio *bio = *bio_ptr;
+	unsigned int i = 0;
+	unsigned int num_sectors = 0;
+	struct bio_vec bv;
+	struct bvec_iter iter;
+
+	bio_for_each_segment(bv, bio, iter) {
+		num_sectors += bv.bv_len >> SECTOR_SHIFT;
+		if (++i == BIO_MAX_PAGES)
+			break;
+	}
+	if (num_sectors < bio_sectors(bio)) {
+		struct bio *split_bio;
+
+		split_bio = bio_split(bio, num_sectors, GFP_NOIO, NULL);
+		if (!split_bio) {
+			bio->bi_status = BLK_STS_RESOURCE;
+			return -ENOMEM;
+		}
+		bio_chain(split_bio, bio);
+		generic_make_request(bio);
+		*bio_ptr = split_bio;
+	}
+	return 0;
+}
+
+/*
+ * The crypto API fallback's encryption routine.
+ * Allocate a bounce bio for encryption, encrypt the input bio using
+ * crypto API, and replace *bio_ptr with the bounce bio. May split input
+ * bio if it's too large.
+ */
+static int blk_crypto_encrypt_bio(struct bio **bio_ptr)
+{
+	struct bio *src_bio;
+	struct skcipher_request *ciph_req = NULL;
+	DECLARE_CRYPTO_WAIT(wait);
+	int err = 0;
+	u64 curr_dun;
+	union {
+		__le64 dun;
+		u8 bytes[16];
+	} iv;
+	struct scatterlist src, dst;
+	struct bio *enc_bio;
+	struct bio_vec *enc_bvec;
+	int i, j;
+	int data_unit_size;
+
+	/* Split the bio if it's too big for single page bvec */
+	err = blk_crypto_split_bio_if_needed(bio_ptr);
+	if (err)
+		return err;
+
+	src_bio = *bio_ptr;
+	data_unit_size = 1 << src_bio->bi_crypt_context->data_unit_size_bits;
+
+	/* Allocate bounce bio for encryption */
+	enc_bio = blk_crypto_clone_bio(src_bio);
+	if (!enc_bio) {
+		src_bio->bi_status = BLK_STS_RESOURCE;
+		return -ENOMEM;
+	}
+
+	/*
+	 * Use the crypto API fallback keyslot manager to get a crypto_skcipher
+	 * for the algorithm and key specified for this bio.
+	 */
+	err = bio_crypt_ctx_acquire_keyslot(src_bio, blk_crypto_ksm);
+	if (err) {
+		src_bio->bi_status = BLK_STS_IOERR;
+		goto out_put_enc_bio;
+	}
+
+	/* and then allocate an skcipher_request for it */
+	err = blk_crypto_alloc_cipher_req(src_bio, &ciph_req, &wait);
+	if (err)
+		goto out_release_keyslot;
+
+	curr_dun = bio_crypt_data_unit_num(src_bio);
+	sg_init_table(&src, 1);
+	sg_init_table(&dst, 1);
+
+	skcipher_request_set_crypt(ciph_req, &src, &dst,
+				   data_unit_size, iv.bytes);
+
+	/* Encrypt each page in the bounce bio */
+	for (i = 0, enc_bvec = enc_bio->bi_io_vec; i < enc_bio->bi_vcnt;
+	     enc_bvec++, i++) {
+		struct page *plaintext_page = enc_bvec->bv_page;
+		struct page *ciphertext_page =
+			mempool_alloc(blk_crypto_page_pool, GFP_NOIO);
+
+		enc_bvec->bv_page = ciphertext_page;
+
+		if (!ciphertext_page) {
+			src_bio->bi_status = BLK_STS_RESOURCE;
+			err = -ENOMEM;
+			goto out_free_bounce_pages;
+		}
+
+		sg_set_page(&src, plaintext_page, data_unit_size,
+			    enc_bvec->bv_offset);
+		sg_set_page(&dst, ciphertext_page, data_unit_size,
+			    enc_bvec->bv_offset);
+
+		/* Encrypt each data unit in this page */
+		for (j = 0; j < enc_bvec->bv_len; j += data_unit_size) {
+			memset(&iv, 0, sizeof(iv));
+			iv.dun = cpu_to_le64(curr_dun);
+
+			err = crypto_wait_req(crypto_skcipher_encrypt(ciph_req),
+					      &wait);
+			if (err) {
+				i++;
+				src_bio->bi_status = BLK_STS_RESOURCE;
+				goto out_free_bounce_pages;
+			}
+			curr_dun++;
+			src.offset += data_unit_size;
+			dst.offset += data_unit_size;
+		}
+	}
+
+	enc_bio->bi_private = src_bio;
+	enc_bio->bi_end_io = blk_crypto_encrypt_endio;
+	*bio_ptr = enc_bio;
+
+	enc_bio = NULL;
+	err = 0;
+	goto out_free_ciph_req;
+
+out_free_bounce_pages:
+	while (i > 0)
+		mempool_free(enc_bio->bi_io_vec[--i].bv_page,
+			     blk_crypto_page_pool);
+out_free_ciph_req:
+	skcipher_request_free(ciph_req);
+out_release_keyslot:
+	bio_crypt_ctx_release_keyslot(src_bio);
+out_put_enc_bio:
+	if (enc_bio)
+		bio_put(enc_bio);
+
+	return err;
+}
+
+/*
+ * The crypto API fallback's main decryption routine.
+ * Decrypts input bio in place.
+ */
+static void blk_crypto_decrypt_bio(struct work_struct *w)
+{
+	struct work_mem *work_mem =
+		container_of(w, struct work_mem, crypto_work);
+	struct bio *bio = work_mem->bio;
+	struct skcipher_request *ciph_req = NULL;
+	DECLARE_CRYPTO_WAIT(wait);
+	struct bio_vec bv;
+	struct bvec_iter iter;
+	u64 curr_dun;
+	union {
+		__le64 dun;
+		u8 bytes[16];
+	} iv;
+	struct scatterlist sg;
+	int data_unit_size = 1 << bio->bi_crypt_context->data_unit_size_bits;
+	int i;
+	int err;
+
+	/*
+	 * Use the crypto API fallback keyslot manager to get a crypto_skcipher
+	 * for the algorithm and key specified for this bio.
+	 */
+	if (bio_crypt_ctx_acquire_keyslot(bio, blk_crypto_ksm)) {
+		bio->bi_status = BLK_STS_RESOURCE;
+		goto out_no_keyslot;
+	}
+
+	/* and then allocate an skcipher_request for it */
+	err = blk_crypto_alloc_cipher_req(bio, &ciph_req, &wait);
+	if (err)
+		goto out;
+
+	curr_dun = bio_crypt_sw_data_unit_num(bio);
+	sg_init_table(&sg, 1);
+	skcipher_request_set_crypt(ciph_req, &sg, &sg, data_unit_size,
+				   iv.bytes);
+
+	/* Decrypt each segment in the bio */
+	__bio_for_each_segment(bv, bio, iter,
+			       bio->bi_crypt_context->crypt_iter) {
+		struct page *page = bv.bv_page;
+
+		sg_set_page(&sg, page, data_unit_size, bv.bv_offset);
+
+		/* Decrypt each data unit in the segment */
+		for (i = 0; i < bv.bv_len; i += data_unit_size) {
+			memset(&iv, 0, sizeof(iv));
+			iv.dun = cpu_to_le64(curr_dun);
+			if (crypto_wait_req(crypto_skcipher_decrypt(ciph_req),
+					    &wait)) {
+				bio->bi_status = BLK_STS_IOERR;
+				goto out;
+			}
+			curr_dun++;
+			sg.offset += data_unit_size;
+		}
+	}
+
+out:
+	skcipher_request_free(ciph_req);
+	bio_crypt_ctx_release_keyslot(bio);
+out_no_keyslot:
+	kmem_cache_free(blk_crypto_work_mem_cache, work_mem);
+	bio_endio(bio);
+}
+
+/* Queue bio for decryption */
+static void blk_crypto_queue_decrypt_bio(struct bio *bio)
+{
+	struct work_mem *work_mem =
+		kmem_cache_zalloc(blk_crypto_work_mem_cache, GFP_ATOMIC);
+
+	if (!work_mem) {
+		bio->bi_status = BLK_STS_RESOURCE;
+		bio_endio(bio);
+		return;
+	}
+
+	INIT_WORK(&work_mem->crypto_work, blk_crypto_decrypt_bio);
+	work_mem->bio = bio;
+	queue_work(blk_crypto_wq, &work_mem->crypto_work);
+}
+
+/**
+ * blk_crypto_submit_bio - handle submitting bio for inline encryption
+ *
+ * @bio_ptr: pointer to original bio pointer
+ *
+ * If the bio doesn't have inline encryption enabled or the submitter already
+ * specified a keyslot for the target device, do nothing.  Else, a raw key must
+ * have been provided, so acquire a device keyslot for it if supported.  Else,
+ * use the crypto API fallback.
+ *
+ * When the crypto API fallback is used for encryption, blk-crypto may choose to
+ * split the bio into 2 - the first one that will continue to be processed and
+ * the second one that will be resubmitted via generic_make_request.
+ * A bounce bio will be allocated to encrypt the contents of the aforementioned
+ * "first one", and *bio_ptr will be updated to this bounce bio.
+ *
+ * Return: 0 if bio submission should continue; nonzero if bio_endio() was
+ *	   already called so bio submission should abort.
+ */
+int blk_crypto_submit_bio(struct bio **bio_ptr)
+{
+	struct bio *bio = *bio_ptr;
+	struct request_queue *q;
+	int err;
+	struct bio_crypt_ctx *crypt_ctx;
+
+	if (!bio_has_crypt_ctx(bio) || !bio_has_data(bio))
+		return 0;
+
+	/*
+	 * When a read bio is marked for sw decryption, its bi_iter is saved
+	 * so that when we decrypt the bio later, we know what part of it was
+	 * marked for sw decryption (when the bio is passed down after
+	 * blk_crypto_submit bio, it may be split or advanced so we cannot rely
+	 * on the bi_iter while decrypting in blk_crypto_endio)
+	 */
+	if (bio_crypt_swhandled(bio))
+		return 0;
+
+	err = bio_crypt_check_alignment(bio);
+	if (err)
+		goto out;
+
+	crypt_ctx = bio->bi_crypt_context;
+	q = bio->bi_disk->queue;
+
+	if (bio_crypt_has_keyslot(bio)) {
+		/* Key already programmed into device? */
+		if (q->ksm == crypt_ctx->processing_ksm)
+			return 0;
+
+		/* Nope, release the existing keyslot. */
+		bio_crypt_ctx_release_keyslot(bio);
+	}
+
+	/* Get device keyslot if supported */
+	if (q->ksm) {
+		err = bio_crypt_ctx_acquire_keyslot(bio, q->ksm);
+		if (!err)
+			return 0;
+
+		pr_warn_once("Failed to acquire keyslot for %s (err=%d).  Falling back to crypto API.\n",
+			     bio->bi_disk->disk_name, err);
+	}
+
+	/* Fallback to crypto API */
+	if (!READ_ONCE(tfms_inited[bio->bi_crypt_context->crypto_mode])) {
+		err = -EIO;
+		bio->bi_status = BLK_STS_IOERR;
+		goto out;
+	}
+
+	if (bio_data_dir(bio) == WRITE) {
+		/* Encrypt the data now */
+		err = blk_crypto_encrypt_bio(bio_ptr);
+		if (err)
+			goto out;
+	} else {
+		/* Mark bio as swhandled */
+		bio->bi_crypt_context->processing_ksm = blk_crypto_ksm;
+		bio->bi_crypt_context->crypt_iter = bio->bi_iter;
+		bio->bi_crypt_context->sw_data_unit_num =
+				bio->bi_crypt_context->data_unit_num;
+	}
+	return 0;
+out:
+	bio_endio(*bio_ptr);
+	return err;
+}
+
+/**
+ * blk_crypto_endio - clean up bio w.r.t inline encryption during bio_endio
+ *
+ * @bio - the bio to clean up
+ *
+ * If blk_crypto_submit_bio decided to fallback to crypto API for this
+ * bio, we queue the bio for decryption into a workqueue and return false,
+ * and call bio_endio(bio) at a later time (after the bio has been decrypted).
+ *
+ * If the bio is not to be decrypted by the crypto API, this function releases
+ * the reference to the keyslot that blk_crypto_submit_bio got.
+ *
+ * Return: true if bio_endio should continue; false otherwise (bio_endio will
+ * be called again when bio has been decrypted).
+ */
+bool blk_crypto_endio(struct bio *bio)
+{
+	if (!bio_has_crypt_ctx(bio))
+		return true;
+
+	if (bio_crypt_swhandled(bio)) {
+		/*
+		 * The only bios that are swhandled when they reach here
+		 * are those with bio_data_dir(bio) == READ, since WRITE
+		 * bios that are encrypted by the crypto API fallback are
+		 * handled by blk_crypto_encrypt_endio.
+		 */
+
+		/* If there was an IO error, don't decrypt. */
+		if (bio->bi_status)
+			return true;
+
+		blk_crypto_queue_decrypt_bio(bio);
+		return false;
+	}
+
+	if (bio_has_crypt_ctx(bio) && bio_crypt_has_keyslot(bio))
+		bio_crypt_ctx_release_keyslot(bio);
+
+	return true;
+}
+
+/*
+ * blk_crypto_mode_alloc_ciphers() - Allocate skciphers for a
+ *				     mode_num for all keyslots
+ * @mode_num - the blk_crypto_mode we want to allocate ciphers for.
+ *
+ * Upper layers (filesystems) should call this function to ensure that a
+ * the crypto API fallback has transforms for this algorithm, if they become
+ * necessary.
+ *
+ */
+int blk_crypto_mode_alloc_ciphers(enum blk_crypto_mode_num mode_num)
+{
+	struct blk_crypto_keyslot *slotp;
+	int err = 0;
+	int i;
+
+	/* Fast path */
+	if (likely(READ_ONCE(tfms_inited[mode_num]))) {
+		/*
+		 * Ensure that updates to blk_crypto_keyslots[i].tfms[mode_num]
+		 * for each i are visible before we try to access them.
+		 */
+		smp_rmb();
+		return 0;
+	}
+
+	mutex_lock(&tfms_lock[mode_num]);
+	if (likely(tfms_inited[mode_num]))
+		goto out;
+
+	for (i = 0; i < blk_crypto_num_keyslots; i++) {
+		slotp = &blk_crypto_keyslots[i];
+		slotp->tfms[mode_num] = crypto_alloc_skcipher(
+					blk_crypto_modes[mode_num].cipher_str,
+					0, 0);
+		if (IS_ERR(slotp->tfms[mode_num])) {
+			err = PTR_ERR(slotp->tfms[mode_num]);
+			slotp->tfms[mode_num] = NULL;
+			goto out_free_tfms;
+		}
+
+		crypto_skcipher_set_flags(slotp->tfms[mode_num],
+					  CRYPTO_TFM_REQ_FORBID_WEAK_KEYS);
+	}
+
+	/*
+	 * Ensure that updates to blk_crypto_keyslots[i].tfms[mode_num]
+	 * for each i are visible before we set tfms_inited[mode_num].
+	 */
+	smp_wmb();
+	WRITE_ONCE(tfms_inited[mode_num], true);
+	goto out;
+
+out_free_tfms:
+	for (i = 0; i < blk_crypto_num_keyslots; i++) {
+		slotp = &blk_crypto_keyslots[i];
+		crypto_free_skcipher(slotp->tfms[mode_num]);
+		slotp->tfms[mode_num] = NULL;
+	}
+out:
+	mutex_unlock(&tfms_lock[mode_num]);
+	return err;
+}
+EXPORT_SYMBOL(blk_crypto_mode_alloc_ciphers);
+
+int __init blk_crypto_init(void)
+{
+	int i;
+	int err = -ENOMEM;
+
+	blk_crypto_ksm = keyslot_manager_create(blk_crypto_num_keyslots,
+						&blk_crypto_ksm_ll_ops,
+						NULL);
+	if (!blk_crypto_ksm)
+		goto out;
+
+	blk_crypto_wq = alloc_workqueue("blk_crypto_wq",
+					WQ_UNBOUND | WQ_HIGHPRI |
+					WQ_MEM_RECLAIM,
+					num_online_cpus());
+	if (!blk_crypto_wq)
+		goto out_free_ksm;
+
+	blk_crypto_keyslots = kcalloc(blk_crypto_num_keyslots,
+				      sizeof(*blk_crypto_keyslots),
+				      GFP_KERNEL);
+	if (!blk_crypto_keyslots)
+		goto out_free_workqueue;
+
+	for (i = 0; i < ARRAY_SIZE(blk_crypto_modes); i++)
+		mutex_init(&tfms_lock[i]);
+
+	blk_crypto_page_pool =
+		mempool_create_page_pool(num_prealloc_bounce_pg, 0);
+	if (!blk_crypto_page_pool)
+		goto out_free_keyslots;
+
+	blk_crypto_work_mem_cache = KMEM_CACHE(work_mem, SLAB_RECLAIM_ACCOUNT);
+	if (!blk_crypto_work_mem_cache)
+		goto out_free_page_pool;
+
+	return 0;
+
+out_free_page_pool:
+	mempool_destroy(blk_crypto_page_pool);
+	blk_crypto_page_pool = NULL;
+out_free_keyslots:
+	kzfree(blk_crypto_keyslots);
+	blk_crypto_keyslots = NULL;
+out_free_workqueue:
+	destroy_workqueue(blk_crypto_wq);
+	blk_crypto_wq = NULL;
+out_free_ksm:
+	keyslot_manager_destroy(blk_crypto_ksm);
+	blk_crypto_ksm = NULL;
+out:
+	pr_warn("No memory for blk-crypto crypto API fallback.");
+	return err;
+}
diff --git a/include/linux/bio-crypt-ctx.h b/include/linux/bio-crypt-ctx.h
index ebe456289338..b9e0515143a4 100644
--- a/include/linux/bio-crypt-ctx.h
+++ b/include/linux/bio-crypt-ctx.h
@@ -60,6 +60,8 @@  static inline void bio_crypt_advance(struct bio *bio, unsigned int bytes)
 	}
 }
 
+extern bool bio_crypt_swhandled(struct bio *bio);
+
 static inline bool bio_crypt_has_keyslot(struct bio *bio)
 {
 	return bio->bi_crypt_context->keyslot >= 0;
@@ -177,6 +179,11 @@  static inline void bio_crypt_set_ctx(struct bio *bio,
 				     unsigned int dun_bits,
 				     gfp_t gfp_mask) { }
 
+static inline bool bio_crypt_swhandled(struct bio *bio)
+{
+	return false;
+}
+
 static inline void bio_set_data_unit_num(struct bio *bio, u64 dun) { }
 
 static inline bool bio_crypt_has_keyslot(struct bio *bio)
diff --git a/include/linux/blk-crypto.h b/include/linux/blk-crypto.h
new file mode 100644
index 000000000000..42dbba33598f
--- /dev/null
+++ b/include/linux/blk-crypto.h
@@ -0,0 +1,47 @@ 
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright 2019 Google LLC
+ */
+
+#ifndef __LINUX_BLK_CRYPTO_H
+#define __LINUX_BLK_CRYPTO_H
+
+#include <linux/types.h>
+#include <linux/bio.h>
+
+#ifdef CONFIG_BLK_INLINE_ENCRYPTION
+
+int blk_crypto_init(void);
+
+int blk_crypto_submit_bio(struct bio **bio_ptr);
+
+bool blk_crypto_endio(struct bio *bio);
+
+int blk_crypto_mode_alloc_ciphers(enum blk_crypto_mode_num mode_num);
+
+#else /* CONFIG_BLK_INLINE_ENCRYPTION */
+
+static inline int blk_crypto_init(void)
+{
+	return 0;
+}
+
+static inline int blk_crypto_submit_bio(struct bio **bio_ptr)
+{
+	return 0;
+}
+
+static inline bool blk_crypto_endio(struct bio *bio)
+{
+	return true;
+}
+
+static inline int
+blk_crypto_mode_alloc_ciphers(enum blk_crypto_mode_num mode_num)
+{
+	return -EOPNOTSUPP;
+}
+
+#endif /* CONFIG_BLK_INLINE_ENCRYPTION */
+
+#endif /* __LINUX_BLK_CRYPTO_H */