diff --git a/block/blk-crypto-fallback.c b/block/blk-crypto-fallback.c
index 195b04b5df0d..ba452cbafd44 100644
--- a/block/blk-crypto-fallback.c
+++ b/block/blk-crypto-fallback.c
@@ -487,21 +487,13 @@ out:
 	return false;
 }
 
-/**
- * blk_crypto_start_using_mode() - Start using a crypto algorithm on a device
- * @mode_num: the blk_crypto_mode we want to allocate ciphers for.
- * @data_unit_size: the data unit size that will be used
- * @q: the request queue for the device
- *
- * Upper layers must call this function to ensure that a the crypto API fallback
- * has transforms for this algorithm, if they become necessary.
- *
- * Return: 0 on success and -err on error.
+/*
+ * Prepare blk-crypto-fallback for the specified crypto mode.
+ * Returns -ENOPKG if the needed crypto API support is missing.
  */
-int blk_crypto_start_using_mode(enum blk_crypto_mode_num mode_num,
-				unsigned int data_unit_size,
-				struct request_queue *q)
+int blk_crypto_fallback_start_using_mode(enum blk_crypto_mode_num mode_num)
 {
+	const char *cipher_str = blk_crypto_modes[mode_num].cipher_str;
 	struct blk_crypto_keyslot *slotp;
 	unsigned int i;
 	int err = 0;
@@ -514,25 +506,20 @@ int blk_crypto_start_using_mode(enum blk_crypto_mode_num mode_num,
 	if (likely(smp_load_acquire(&tfms_inited[mode_num])))
 		return 0;
 
-	/*
-	 * If the keyslot manager of the request queue supports this
-	 * crypto mode, then we don't need to allocate this mode.
-	 */
-	if (keyslot_manager_crypto_mode_supported(q->ksm, mode_num,
-						  data_unit_size))
-		return 0;
-
 	mutex_lock(&tfms_init_lock);
 	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);
+		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]);
+			if (err == -ENOENT) {
+				pr_warn_once("Missing crypto API support for \"%s\"\n",
+					     cipher_str);
+				err = -ENOPKG;
+			}
 			slotp->tfms[mode_num] = NULL;
 			goto out_free_tfms;
 		}
@@ -558,7 +545,6 @@ out:
 	mutex_unlock(&tfms_init_lock);
 	return err;
 }
-EXPORT_SYMBOL_GPL(blk_crypto_start_using_mode);
 
 int blk_crypto_fallback_evict_key(const struct blk_crypto_key *key)
 {
diff --git a/block/blk-crypto-internal.h b/block/blk-crypto-internal.h
index 40d826b743da..4da998c803f2 100644
--- a/block/blk-crypto-internal.h
+++ b/block/blk-crypto-internal.h
@@ -19,6 +19,8 @@ extern const struct blk_crypto_mode blk_crypto_modes[];
 
 #ifdef CONFIG_BLK_INLINE_ENCRYPTION_FALLBACK
 
+int blk_crypto_fallback_start_using_mode(enum blk_crypto_mode_num mode_num);
+
 int blk_crypto_fallback_submit_bio(struct bio **bio_ptr);
 
 bool blk_crypto_queue_decrypt_bio(struct bio *bio);
@@ -29,6 +31,13 @@ bool bio_crypt_fallback_crypted(const struct bio_crypt_ctx *bc);
 
 #else /* CONFIG_BLK_INLINE_ENCRYPTION_FALLBACK */
 
+static inline int
+blk_crypto_fallback_start_using_mode(enum blk_crypto_mode_num mode_num)
+{
+	pr_warn_once("crypto API fallback is disabled\n");
+	return -ENOPKG;
+}
+
 static inline bool bio_crypt_fallback_crypted(const struct bio_crypt_ctx *bc)
 {
 	return false;
diff --git a/block/blk-crypto.c b/block/blk-crypto.c
index 88df1c0e7e5f..7bf2ff86d277 100644
--- a/block/blk-crypto.c
+++ b/block/blk-crypto.c
@@ -232,6 +232,31 @@ int blk_crypto_init_key(struct blk_crypto_key *blk_key,
 }
 EXPORT_SYMBOL_GPL(blk_crypto_init_key);
 
+/**
+ * blk_crypto_start_using_mode() - Start using blk-crypto on a device
+ * @crypto_mode: the crypto mode that will be used
+ * @data_unit_size: the data unit size that will be used
+ * @q: the request queue for the device
+ *
+ * Upper layers must call this function to ensure that either the hardware
+ * supports the needed crypto settings, or the crypto API fallback has
+ * transforms for the needed mode allocated and ready to go.
+ *
+ * Return: 0 on success; -ENOPKG if the hardware doesn't support the crypto
+ *	   settings and blk-crypto-fallback is either disabled or the needed
+ *	   algorithm is disabled in the crypto API; or another -errno code.
+ */
+int blk_crypto_start_using_mode(enum blk_crypto_mode_num crypto_mode,
+				unsigned int data_unit_size,
+				struct request_queue *q)
+{
+	if (keyslot_manager_crypto_mode_supported(q->ksm, crypto_mode,
+						  data_unit_size))
+		return 0;
+	return blk_crypto_fallback_start_using_mode(crypto_mode);
+}
+EXPORT_SYMBOL_GPL(blk_crypto_start_using_mode);
+
 /**
  * blk_crypto_evict_key() - Evict a key from any inline encryption hardware
  *			    it may have been programmed into
diff --git a/include/linux/blk-crypto.h b/include/linux/blk-crypto.h
index 2d871a7a0f5a..2416a0a6e6b3 100644
--- a/include/linux/blk-crypto.h
+++ b/include/linux/blk-crypto.h
@@ -20,6 +20,10 @@ int blk_crypto_init_key(struct blk_crypto_key *blk_key,
 			enum blk_crypto_mode_num crypto_mode,
 			unsigned int data_unit_size);
 
+int blk_crypto_start_using_mode(enum blk_crypto_mode_num crypto_mode,
+				unsigned int data_unit_size,
+				struct request_queue *q);
+
 int blk_crypto_evict_key(struct request_queue *q,
 			 const struct blk_crypto_key *key);
 
@@ -39,22 +43,10 @@ static inline bool blk_crypto_endio(struct bio *bio)
 
 #ifdef CONFIG_BLK_INLINE_ENCRYPTION_FALLBACK
 
-int blk_crypto_start_using_mode(enum blk_crypto_mode_num mode_num,
-				unsigned int data_unit_size,
-				struct request_queue *q);
-
 int blk_crypto_fallback_init(void);
 
 #else /* CONFIG_BLK_INLINE_ENCRYPTION_FALLBACK */
 
-static inline int
-blk_crypto_start_using_mode(enum blk_crypto_mode_num mode_num,
-			    unsigned int data_unit_size,
-			    struct request_queue *q)
-{
-	return 0;
-}
-
 static inline int blk_crypto_fallback_init(void)
 {
 	return 0;