diff mbox series

[2/5] blk-crypto-fallback: consolidate static variables

Message ID 20210913013135.102404-3-ebiggers@kernel.org (mailing list archive)
State New, archived
Headers show
Series blk-crypto cleanups | expand

Commit Message

Eric Biggers Sept. 13, 2021, 1:31 a.m. UTC 
From: Eric Biggers <ebiggers@google.com>

blk-crypto-fallback.c has many static variables with inconsistent names,
e.g. "blk_crypto_*", "crypto_*", and some unprefixed names.  This is
confusing.  Consolidate them all into a struct named
"blk_crypto_fallback" so that it's clear what they are.

Signed-off-by: Eric Biggers <ebiggers@google.com>
---
 block/blk-crypto-fallback.c | 251 +++++++++++++++++++-----------------
 1 file changed, 136 insertions(+), 115 deletions(-)

Comments

Christoph Hellwig Sept. 15, 2021, 7:39 a.m. UTC | #1 
On Sun, Sep 12, 2021 at 06:31:32PM -0700, Eric Biggers wrote:
> From: Eric Biggers <ebiggers@google.com>
> 
> blk-crypto-fallback.c has many static variables with inconsistent names,
> e.g. "blk_crypto_*", "crypto_*", and some unprefixed names.  This is
> confusing.  Consolidate them all into a struct named
> "blk_crypto_fallback" so that it's clear what they are.

I always find this pattern of a single instance global struct rather
confusing.  What is the advantage over just using a consistent prefix?
Eric Biggers Sept. 15, 2021, 5:50 p.m. UTC | #2 
On Wed, Sep 15, 2021 at 08:39:53AM +0100, Christoph Hellwig wrote:
> On Sun, Sep 12, 2021 at 06:31:32PM -0700, Eric Biggers wrote:
> > From: Eric Biggers <ebiggers@google.com>
> > 
> > blk-crypto-fallback.c has many static variables with inconsistent names,
> > e.g. "blk_crypto_*", "crypto_*", and some unprefixed names.  This is
> > confusing.  Consolidate them all into a struct named
> > "blk_crypto_fallback" so that it's clear what they are.
> 
> I always find this pattern of a single instance global struct rather
> confusing.  What is the advantage over just using a consistent prefix?

Using "blk_crypto_fallback_*" for all these variables results in some pretty
long names, e.g. "blk_crypto_fallback_crypt_ctx_cache" and
"blk_crypto_fallback_num_prealloc_crypt_ctxs".  This proposal gives the best of
both worlds; the names are properly "namespaced" but there is also a shortcut to
refer to them (struct blk_crypto_fallback *fallback = &blk_crypto_fallback).

If this is going to be controversial I can just drop this patch, but I was
hoping there would be a way to make things more consistent.

- Eric
Christoph Hellwig Sept. 16, 2021, 7:39 a.m. UTC | #3 
On Wed, Sep 15, 2021 at 10:50:13AM -0700, Eric Biggers wrote:
> Using "blk_crypto_fallback_*" for all these variables results in some pretty
> long names, e.g. "blk_crypto_fallback_crypt_ctx_cache" and
> "blk_crypto_fallback_num_prealloc_crypt_ctxs".  This proposal gives the best of
> both worlds; the names are properly "namespaced" but there is also a shortcut to
> refer to them (struct blk_crypto_fallback *fallback = &blk_crypto_fallback).

I'd just drop the second crypt in those.

> If this is going to be controversial I can just drop this patch, but I was
> hoping there would be a way to make things more consistent.

I personally detest that pattern.  Not sure if that counts as
controversial or even matters :)
Eric Biggers Sept. 16, 2021, 5:28 p.m. UTC | #4 
On Thu, Sep 16, 2021 at 08:39:54AM +0100, Christoph Hellwig wrote:
> On Wed, Sep 15, 2021 at 10:50:13AM -0700, Eric Biggers wrote:
> > Using "blk_crypto_fallback_*" for all these variables results in some pretty
> > long names, e.g. "blk_crypto_fallback_crypt_ctx_cache" and
> > "blk_crypto_fallback_num_prealloc_crypt_ctxs".  This proposal gives the best of
> > both worlds; the names are properly "namespaced" but there is also a shortcut to
> > refer to them (struct blk_crypto_fallback *fallback = &blk_crypto_fallback).
> 
> I'd just drop the second crypt in those.
> 
> > If this is going to be controversial I can just drop this patch, but I was
> > hoping there would be a way to make things more consistent.
> 
> I personally detest that pattern.  Not sure if that counts as
> controversial or even matters :)

The names are still pretty long even with the second "crypt" dropped from those
two.  How about just "fallback_*"?  It might be clear enough from the context.

Anyway, I've dropped this patch from the series for now.  This can be done later
we can agree on which approach to take.

- Eric
diff mbox series

Patch

diff --git a/block/blk-crypto-fallback.c b/block/blk-crypto-fallback.c
index 82b302597b474..a4a444c83fb3c 100644
--- a/block/blk-crypto-fallback.c
+++ b/block/blk-crypto-fallback.c
@@ -21,20 +21,10 @@ 
 
 #include "blk-crypto-internal.h"
 
-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 the blk-crypto crypto API fallback");
-
-static unsigned int blk_crypto_num_keyslots = 100;
-module_param_named(num_keyslots, blk_crypto_num_keyslots, uint, 0);
-MODULE_PARM_DESC(num_keyslots,
-		 "Number of keyslots for the blk-crypto crypto API fallback");
-
-static unsigned int num_prealloc_fallback_crypt_ctxs = 128;
-module_param(num_prealloc_fallback_crypt_ctxs, uint, 0);
-MODULE_PARM_DESC(num_prealloc_crypt_fallback_ctxs,
-		 "Number of preallocated bio fallback crypto contexts for blk-crypto to use during crypto API fallback");
+struct blk_crypto_fallback_keyslot {
+	enum blk_crypto_mode_num crypto_mode;
+	struct crypto_skcipher *tfms[BLK_ENCRYPTION_MODE_MAX];
+};
 
 struct bio_fallback_crypt_ctx {
 	struct bio_crypt_ctx crypt_ctx;
@@ -57,47 +47,80 @@  struct bio_fallback_crypt_ctx {
 	};
 };
 
-static struct kmem_cache *bio_fallback_crypt_ctx_cache;
-static mempool_t *bio_fallback_crypt_ctx_pool;
+/* All state for blk-crypto-fallback */
+static struct blk_crypto_fallback {
+	unsigned int num_prealloc_bounce_pg;
+	unsigned int num_keyslots;
+	unsigned int num_prealloc_crypt_ctxs;
 
-/*
- * Allocating a crypto tfm during I/O can deadlock, so we have to preallocate
- * all of 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 - the rest of the unused tfms have their keys cleared.
- */
-static DEFINE_MUTEX(tfms_init_lock);
-static bool tfms_inited[BLK_ENCRYPTION_MODE_MAX];
+	bool initialized;
 
-static struct blk_crypto_fallback_keyslot {
-	enum blk_crypto_mode_num crypto_mode;
-	struct crypto_skcipher *tfms[BLK_ENCRYPTION_MODE_MAX];
-} *blk_crypto_keyslots;
+	/*
+	 * This is the key we set when evicting a keyslot. This *should* be the
+	 * all 0's key, but AES-XTS rejects that key, so we use some random
+	 * bytes instead.
+	 */
+	u8 blank_key[BLK_CRYPTO_MAX_KEY_SIZE];
 
-static struct blk_keyslot_manager blk_crypto_ksm;
-static struct workqueue_struct *blk_crypto_wq;
-static mempool_t *blk_crypto_bounce_page_pool;
-static struct bio_set crypto_bio_split;
+	struct bio_set bio_split;
 
-/*
- * This is the key we set when evicting a keyslot. This *should* be the all 0's
- * key, but AES-XTS rejects that key, so we use some random bytes instead.
- */
-static u8 blank_key[BLK_CRYPTO_MAX_KEY_SIZE];
+	struct blk_keyslot_manager ksm;
+
+	struct workqueue_struct *decrypt_wq;
+
+	struct blk_crypto_fallback_keyslot *keyslots;
+
+	mempool_t *bounce_page_pool;
+	struct kmem_cache *crypt_ctx_cache;
+	mempool_t *crypt_ctx_pool;
+
+	/*
+	 * Allocating a crypto tfm during I/O can deadlock, so we have to
+	 * preallocate all of 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
+	 * - the rest of the unused tfms have their keys cleared.
+	 */
+	struct mutex tfms_init_lock;
+	bool tfms_inited[BLK_ENCRYPTION_MODE_MAX];
+
+} blk_crypto_fallback = {
+	.num_prealloc_bounce_pg = 32,
+	.num_keyslots = 100,
+	.num_prealloc_crypt_ctxs = 128,
+	.tfms_init_lock =
+		__MUTEX_INITIALIZER(blk_crypto_fallback.tfms_init_lock),
+};
+
+module_param_named(num_prealloc_bounce_pg,
+		   blk_crypto_fallback.num_prealloc_bounce_pg, uint, 0);
+MODULE_PARM_DESC(num_prealloc_bounce_pg,
+		 "Number of preallocated bounce pages for the blk-crypto crypto API fallback");
+
+module_param_named(num_keyslots, blk_crypto_fallback.num_keyslots, uint, 0);
+MODULE_PARM_DESC(num_keyslots,
+		 "Number of keyslots for the blk-crypto crypto API fallback");
+
+module_param_named(num_prealloc_fallback_crypt_ctxs,
+		   blk_crypto_fallback.num_prealloc_crypt_ctxs, uint, 0);
+MODULE_PARM_DESC(num_prealloc_crypt_fallback_ctxs,
+		 "Number of preallocated bio fallback crypto contexts for blk-crypto to use during crypto API fallback");
 
 static void blk_crypto_fallback_evict_keyslot(unsigned int slot)
 {
-	struct blk_crypto_fallback_keyslot *slotp = &blk_crypto_keyslots[slot];
+	struct blk_crypto_fallback *fallback = &blk_crypto_fallback;
+	struct blk_crypto_fallback_keyslot *slotp = &fallback->keyslots[slot];
 	enum blk_crypto_mode_num crypto_mode = slotp->crypto_mode;
 	int err;
 
 	WARN_ON(slotp->crypto_mode == BLK_ENCRYPTION_MODE_INVALID);
 
 	/* Clear the key in the skcipher */
-	err = crypto_skcipher_setkey(slotp->tfms[crypto_mode], blank_key,
+	err = crypto_skcipher_setkey(slotp->tfms[crypto_mode],
+				     fallback->blank_key,
 				     blk_crypto_modes[crypto_mode].keysize);
 	WARN_ON(err);
 	slotp->crypto_mode = BLK_ENCRYPTION_MODE_INVALID;
@@ -107,7 +130,8 @@  static int blk_crypto_fallback_keyslot_program(struct blk_keyslot_manager *ksm,
 					       const struct blk_crypto_key *key,
 					       unsigned int slot)
 {
-	struct blk_crypto_fallback_keyslot *slotp = &blk_crypto_keyslots[slot];
+	struct blk_crypto_fallback *fallback = &blk_crypto_fallback;
+	struct blk_crypto_fallback_keyslot *slotp = &fallback->keyslots[slot];
 	const enum blk_crypto_mode_num crypto_mode =
 						key->crypto_cfg.crypto_mode;
 	int err;
@@ -134,16 +158,6 @@  static int blk_crypto_fallback_keyslot_evict(struct blk_keyslot_manager *ksm,
 	return 0;
 }
 
-/*
- * The crypto API fallback KSM ops - only used for a bio when it specifies a
- * blk_crypto_key that was not supported by the device's inline encryption
- * hardware.
- */
-static const struct blk_ksm_ll_ops blk_crypto_ksm_ll_ops = {
-	.keyslot_program	= blk_crypto_fallback_keyslot_program,
-	.keyslot_evict		= blk_crypto_fallback_keyslot_evict,
-};
-
 static void blk_crypto_fallback_encrypt_endio(struct bio *enc_bio)
 {
 	struct bio *src_bio = enc_bio->bi_private;
@@ -151,7 +165,7 @@  static void blk_crypto_fallback_encrypt_endio(struct bio *enc_bio)
 
 	for (i = 0; i < enc_bio->bi_vcnt; i++)
 		mempool_free(enc_bio->bi_io_vec[i].bv_page,
-			     blk_crypto_bounce_page_pool);
+			     blk_crypto_fallback.bounce_page_pool);
 
 	src_bio->bi_status = enc_bio->bi_status;
 
@@ -195,7 +209,7 @@  blk_crypto_fallback_alloc_cipher_req(struct blk_ksm_keyslot *slot,
 	const struct blk_crypto_fallback_keyslot *slotp;
 	int keyslot_idx = blk_ksm_get_slot_idx(slot);
 
-	slotp = &blk_crypto_keyslots[keyslot_idx];
+	slotp = &blk_crypto_fallback.keyslots[keyslot_idx];
 	ciph_req = skcipher_request_alloc(slotp->tfms[slotp->crypto_mode],
 					  GFP_NOIO);
 	if (!ciph_req)
@@ -227,7 +241,7 @@  static bool blk_crypto_fallback_split_bio_if_needed(struct bio **bio_ptr)
 		struct bio *split_bio;
 
 		split_bio = bio_split(bio, num_sectors, GFP_NOIO,
-				      &crypto_bio_split);
+				      &blk_crypto_fallback.bio_split);
 		if (!split_bio) {
 			bio->bi_status = BLK_STS_RESOURCE;
 			return false;
@@ -263,6 +277,7 @@  static void blk_crypto_dun_to_iv(const u64 dun[BLK_CRYPTO_DUN_ARRAY_SIZE],
  */
 static bool blk_crypto_fallback_encrypt_bio(struct bio **bio_ptr)
 {
+	struct blk_crypto_fallback *fallback = &blk_crypto_fallback;
 	struct bio *src_bio, *enc_bio;
 	struct bio_crypt_ctx *bc;
 	struct blk_ksm_keyslot *slot;
@@ -295,7 +310,7 @@  static bool blk_crypto_fallback_encrypt_bio(struct bio **bio_ptr)
 	 * Use the crypto API fallback keyslot manager to get a crypto_skcipher
 	 * for the algorithm and key specified for this bio.
 	 */
-	blk_st = blk_ksm_get_slot_for_key(&blk_crypto_ksm, bc->bc_key, &slot);
+	blk_st = blk_ksm_get_slot_for_key(&fallback->ksm, bc->bc_key, &slot);
 	if (blk_st != BLK_STS_OK) {
 		src_bio->bi_status = blk_st;
 		goto out_put_enc_bio;
@@ -319,7 +334,7 @@  static bool blk_crypto_fallback_encrypt_bio(struct bio **bio_ptr)
 		struct bio_vec *enc_bvec = &enc_bio->bi_io_vec[i];
 		struct page *plaintext_page = enc_bvec->bv_page;
 		struct page *ciphertext_page =
-			mempool_alloc(blk_crypto_bounce_page_pool, GFP_NOIO);
+			mempool_alloc(fallback->bounce_page_pool, GFP_NOIO);
 
 		enc_bvec->bv_page = ciphertext_page;
 
@@ -359,7 +374,7 @@  static bool blk_crypto_fallback_encrypt_bio(struct bio **bio_ptr)
 out_free_bounce_pages:
 	while (i > 0)
 		mempool_free(enc_bio->bi_io_vec[--i].bv_page,
-			     blk_crypto_bounce_page_pool);
+			     fallback->bounce_page_pool);
 out_free_ciph_req:
 	skcipher_request_free(ciph_req);
 out_release_keyslot:
@@ -377,6 +392,7 @@  static bool blk_crypto_fallback_encrypt_bio(struct bio **bio_ptr)
  */
 static void blk_crypto_fallback_decrypt_bio(struct work_struct *work)
 {
+	struct blk_crypto_fallback *fallback = &blk_crypto_fallback;
 	struct bio_fallback_crypt_ctx *f_ctx =
 		container_of(work, struct bio_fallback_crypt_ctx, work);
 	struct bio *bio = f_ctx->bio;
@@ -397,7 +413,7 @@  static void blk_crypto_fallback_decrypt_bio(struct work_struct *work)
 	 * Use the crypto API fallback keyslot manager to get a crypto_skcipher
 	 * for the algorithm and key specified for this bio.
 	 */
-	blk_st = blk_ksm_get_slot_for_key(&blk_crypto_ksm, bc->bc_key, &slot);
+	blk_st = blk_ksm_get_slot_for_key(&fallback->ksm, bc->bc_key, &slot);
 	if (blk_st != BLK_STS_OK) {
 		bio->bi_status = blk_st;
 		goto out_no_keyslot;
@@ -437,7 +453,7 @@  static void blk_crypto_fallback_decrypt_bio(struct work_struct *work)
 	skcipher_request_free(ciph_req);
 	blk_ksm_put_slot(slot);
 out_no_keyslot:
-	mempool_free(f_ctx, bio_fallback_crypt_ctx_pool);
+	mempool_free(f_ctx, fallback->crypt_ctx_pool);
 	bio_endio(bio);
 }
 
@@ -458,14 +474,14 @@  static void blk_crypto_fallback_decrypt_endio(struct bio *bio)
 
 	/* If there was an IO error, don't queue for decrypt. */
 	if (bio->bi_status) {
-		mempool_free(f_ctx, bio_fallback_crypt_ctx_pool);
+		mempool_free(f_ctx, blk_crypto_fallback.crypt_ctx_pool);
 		bio_endio(bio);
 		return;
 	}
 
 	INIT_WORK(&f_ctx->work, blk_crypto_fallback_decrypt_bio);
 	f_ctx->bio = bio;
-	queue_work(blk_crypto_wq, &f_ctx->work);
+	queue_work(blk_crypto_fallback.decrypt_wq, &f_ctx->work);
 }
 
 /**
@@ -490,17 +506,19 @@  static void blk_crypto_fallback_decrypt_endio(struct bio *bio)
  */
 bool blk_crypto_fallback_bio_prep(struct bio **bio_ptr)
 {
+	struct blk_crypto_fallback *fallback = &blk_crypto_fallback;
 	struct bio *bio = *bio_ptr;
 	struct bio_crypt_ctx *bc = bio->bi_crypt_context;
 	struct bio_fallback_crypt_ctx *f_ctx;
 
-	if (WARN_ON_ONCE(!tfms_inited[bc->bc_key->crypto_cfg.crypto_mode])) {
+	if (WARN_ON_ONCE(!fallback->tfms_inited[
+				bc->bc_key->crypto_cfg.crypto_mode])) {
 		/* User didn't call blk_crypto_start_using_key() first */
 		bio->bi_status = BLK_STS_IOERR;
 		return false;
 	}
 
-	if (!blk_ksm_crypto_cfg_supported(&blk_crypto_ksm,
+	if (!blk_ksm_crypto_cfg_supported(&fallback->ksm,
 					  &bc->bc_key->crypto_cfg)) {
 		bio->bi_status = BLK_STS_NOTSUPP;
 		return false;
@@ -513,7 +531,7 @@  bool blk_crypto_fallback_bio_prep(struct bio **bio_ptr)
 	 * bio READ case: Set up a f_ctx in the bio's bi_private and set the
 	 * bi_end_io appropriately to trigger decryption when the bio is ended.
 	 */
-	f_ctx = mempool_alloc(bio_fallback_crypt_ctx_pool, GFP_NOIO);
+	f_ctx = mempool_alloc(fallback->crypt_ctx_pool, GFP_NOIO);
 	f_ctx->crypt_ctx = *bc;
 	f_ctx->crypt_iter = bio->bi_iter;
 	f_ctx->bi_private_orig = bio->bi_private;
@@ -527,79 +545,82 @@  bool blk_crypto_fallback_bio_prep(struct bio **bio_ptr)
 
 int blk_crypto_fallback_evict_key(const struct blk_crypto_key *key)
 {
-	return blk_ksm_evict_key(&blk_crypto_ksm, key);
+	return blk_ksm_evict_key(&blk_crypto_fallback.ksm, key);
 }
 
-static bool blk_crypto_fallback_inited;
 static int blk_crypto_fallback_init(void)
 {
+	struct blk_crypto_fallback *fallback = &blk_crypto_fallback;
 	int i;
 	int err;
 
-	if (blk_crypto_fallback_inited)
+	if (fallback->initialized)
 		return 0;
 
-	prandom_bytes(blank_key, BLK_CRYPTO_MAX_KEY_SIZE);
+	prandom_bytes(fallback->blank_key, BLK_CRYPTO_MAX_KEY_SIZE);
 
-	err = bioset_init(&crypto_bio_split, 64, 0, 0);
+	err = bioset_init(&fallback->bio_split, 64, 0, 0);
 	if (err)
 		goto out;
 
-	err = blk_ksm_init(&blk_crypto_ksm, blk_crypto_num_keyslots);
+	err = blk_ksm_init(&fallback->ksm, fallback->num_keyslots);
 	if (err)
 		goto fail_free_bioset;
 	err = -ENOMEM;
 
-	blk_crypto_ksm.ksm_ll_ops = blk_crypto_ksm_ll_ops;
-	blk_crypto_ksm.max_dun_bytes_supported = BLK_CRYPTO_MAX_IV_SIZE;
+	fallback->ksm.ksm_ll_ops.keyslot_program =
+		blk_crypto_fallback_keyslot_program;
+	fallback->ksm.ksm_ll_ops.keyslot_evict =
+		blk_crypto_fallback_keyslot_evict;
+	fallback->ksm.max_dun_bytes_supported = BLK_CRYPTO_MAX_IV_SIZE;
 
 	/* All blk-crypto modes have a crypto API fallback. */
 	for (i = 0; i < BLK_ENCRYPTION_MODE_MAX; i++)
-		blk_crypto_ksm.crypto_modes_supported[i] = 0xFFFFFFFF;
-	blk_crypto_ksm.crypto_modes_supported[BLK_ENCRYPTION_MODE_INVALID] = 0;
-
-	blk_crypto_wq = alloc_workqueue("blk_crypto_wq",
-					WQ_UNBOUND | WQ_HIGHPRI |
-					WQ_MEM_RECLAIM, num_online_cpus());
-	if (!blk_crypto_wq)
+		fallback->ksm.crypto_modes_supported[i] = 0xFFFFFFFF;
+	fallback->ksm.crypto_modes_supported[BLK_ENCRYPTION_MODE_INVALID] = 0;
+
+	fallback->decrypt_wq = alloc_workqueue("blk_crypto_fallback_wq",
+					       WQ_UNBOUND | WQ_HIGHPRI |
+					       WQ_MEM_RECLAIM,
+					       num_online_cpus());
+	if (!fallback->decrypt_wq)
 		goto fail_free_ksm;
 
-	blk_crypto_keyslots = kcalloc(blk_crypto_num_keyslots,
-				      sizeof(blk_crypto_keyslots[0]),
-				      GFP_KERNEL);
-	if (!blk_crypto_keyslots)
+	fallback->keyslots = kcalloc(fallback->num_keyslots,
+				     sizeof(fallback->keyslots[0]), GFP_KERNEL);
+	if (!fallback->keyslots)
 		goto fail_free_wq;
 
-	blk_crypto_bounce_page_pool =
-		mempool_create_page_pool(num_prealloc_bounce_pg, 0);
-	if (!blk_crypto_bounce_page_pool)
+	fallback->bounce_page_pool =
+		mempool_create_page_pool(fallback->num_prealloc_bounce_pg, 0);
+	if (!fallback->bounce_page_pool)
 		goto fail_free_keyslots;
 
-	bio_fallback_crypt_ctx_cache = KMEM_CACHE(bio_fallback_crypt_ctx, 0);
-	if (!bio_fallback_crypt_ctx_cache)
+	fallback->crypt_ctx_cache = KMEM_CACHE(bio_fallback_crypt_ctx, 0);
+	if (!fallback->crypt_ctx_cache)
 		goto fail_free_bounce_page_pool;
 
-	bio_fallback_crypt_ctx_pool =
-		mempool_create_slab_pool(num_prealloc_fallback_crypt_ctxs,
-					 bio_fallback_crypt_ctx_cache);
-	if (!bio_fallback_crypt_ctx_pool)
+	fallback->crypt_ctx_pool =
+		mempool_create_slab_pool(fallback->num_prealloc_crypt_ctxs,
+					 fallback->crypt_ctx_cache);
+	if (!fallback->crypt_ctx_pool)
 		goto fail_free_crypt_ctx_cache;
 
-	blk_crypto_fallback_inited = true;
+	fallback->initialized = true;
 
 	return 0;
 fail_free_crypt_ctx_cache:
-	kmem_cache_destroy(bio_fallback_crypt_ctx_cache);
+	kmem_cache_destroy(fallback->crypt_ctx_cache);
 fail_free_bounce_page_pool:
-	mempool_destroy(blk_crypto_bounce_page_pool);
+	mempool_destroy(fallback->bounce_page_pool);
 fail_free_keyslots:
-	kfree(blk_crypto_keyslots);
+	kfree(fallback->keyslots);
 fail_free_wq:
-	destroy_workqueue(blk_crypto_wq);
+	destroy_workqueue(fallback->decrypt_wq);
 fail_free_ksm:
-	blk_ksm_destroy(&blk_crypto_ksm);
+	blk_ksm_destroy(&fallback->ksm);
 fail_free_bioset:
-	bioset_exit(&crypto_bio_split);
+	bioset_exit(&fallback->bio_split);
 out:
 	return err;
 }
@@ -610,29 +631,29 @@  static int blk_crypto_fallback_init(void)
  */
 int blk_crypto_fallback_start_using_mode(enum blk_crypto_mode_num mode_num)
 {
+	struct blk_crypto_fallback *fallback = &blk_crypto_fallback;
 	const char *cipher_str = blk_crypto_modes[mode_num].cipher_str;
 	struct blk_crypto_fallback_keyslot *slotp;
 	unsigned int i;
 	int err = 0;
 
 	/*
-	 * Fast path
-	 * Ensure that updates to blk_crypto_keyslots[i].tfms[mode_num]
-	 * for each i are visible before we try to access them.
+	 * Fast path.  Ensure that updates to keyslots[i].tfms[mode_num] for
+	 * each i are visible before we try to access them.
 	 */
-	if (likely(smp_load_acquire(&tfms_inited[mode_num])))
+	if (likely(smp_load_acquire(&fallback->tfms_inited[mode_num])))
 		return 0;
 
-	mutex_lock(&tfms_init_lock);
-	if (tfms_inited[mode_num])
+	mutex_lock(&fallback->tfms_init_lock);
+	if (fallback->tfms_inited[mode_num])
 		goto out;
 
 	err = blk_crypto_fallback_init();
 	if (err)
 		goto out;
 
-	for (i = 0; i < blk_crypto_num_keyslots; i++) {
-		slotp = &blk_crypto_keyslots[i];
+	for (i = 0; i < fallback->num_keyslots; i++) {
+		slotp = &fallback->keyslots[i];
 		slotp->tfms[mode_num] = crypto_alloc_skcipher(cipher_str, 0, 0);
 		if (IS_ERR(slotp->tfms[mode_num])) {
 			err = PTR_ERR(slotp->tfms[mode_num]);
@@ -650,19 +671,19 @@  int blk_crypto_fallback_start_using_mode(enum blk_crypto_mode_num mode_num)
 	}
 
 	/*
-	 * Ensure that updates to blk_crypto_keyslots[i].tfms[mode_num]
-	 * for each i are visible before we set tfms_inited[mode_num].
+	 * Ensure that updates to keyslots[i].tfms[mode_num] for each i are
+	 * visible before we set tfms_inited[mode_num].
 	 */
-	smp_store_release(&tfms_inited[mode_num], true);
+	smp_store_release(&fallback->tfms_inited[mode_num], true);
 	goto out;
 
 out_free_tfms:
-	for (i = 0; i < blk_crypto_num_keyslots; i++) {
-		slotp = &blk_crypto_keyslots[i];
+	for (i = 0; i < fallback->num_keyslots; i++) {
+		slotp = &fallback->keyslots[i];
 		crypto_free_skcipher(slotp->tfms[mode_num]);
 		slotp->tfms[mode_num] = NULL;
 	}
 out:
-	mutex_unlock(&tfms_init_lock);
+	mutex_unlock(&fallback->tfms_init_lock);
 	return err;
 }