blk-crypto: Remove unused function blk_crypto_config_supported()

blk_crypto_config_supported() is no longer called, so remove it.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://patch.msgid.link/20260718214655.63186-6-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>

Documentation/block/inline-encryption.rst

@@ -185,20 +185,12 @@ blk-crypto-fallback is optional and is controlled by the
 API presented to users of the block layer
 =========================================
 
-``blk_crypto_config_supported()`` allows users to check ahead of time whether
-inline encryption with particular crypto settings will work on a particular
-block_device -- either via hardware or via blk-crypto-fallback.  This function
-takes in a ``struct blk_crypto_config`` which is like blk_crypto_key, but omits
-the actual bytes of the key and instead just contains the algorithm, data unit
-size, etc.  This function can be useful if blk-crypto-fallback is disabled.
-
 ``blk_crypto_init_key()`` allows users to initialize a blk_crypto_key.
 
 Users must call ``blk_crypto_start_using_key()`` before actually starting to use
-a blk_crypto_key on a block_device (even if ``blk_crypto_config_supported()``
-was called earlier).  This is needed to initialize blk-crypto-fallback if it
-will be needed.  This must not be called from the data path, as this may have to
-allocate resources, which may deadlock in that case.
+a blk_crypto_key on a block_device.  This is needed to initialize
+blk-crypto-fallback if it will be needed.  This must not be called from the data
+path, as this may have to allocate resources, which may deadlock in that case.
 
 Next, to attach an encryption context to a bio, users should call
 ``bio_crypt_set_ctx()``.  This function allocates a bio_crypt_ctx and attaches
@@ -220,16 +212,15 @@ any kernel data structures it may be linked into.
 In summary, for users of the block layer, the lifecycle of a blk_crypto_key is
 as follows:
 
-1. ``blk_crypto_config_supported()`` (optional)
-2. ``blk_crypto_init_key()``
-3. ``blk_crypto_start_using_key()``
-4. ``bio_crypt_set_ctx()`` (potentially many times)
-5. ``blk_crypto_evict_key()`` (after all I/O has completed)
-6. Zeroize the blk_crypto_key (this has no dedicated function)
+1. ``blk_crypto_init_key()``
+2. ``blk_crypto_start_using_key()``
+3. ``bio_crypt_set_ctx()`` (potentially many times)
+4. ``blk_crypto_evict_key()`` (after all I/O has completed)
+5. Zeroize the blk_crypto_key (this has no dedicated function)
 
 If a blk_crypto_key is being used on multiple block_devices, then
-``blk_crypto_config_supported()`` (if used), ``blk_crypto_start_using_key()``,
-and ``blk_crypto_evict_key()`` must be called on each block_device.
+``blk_crypto_start_using_key()`` and ``blk_crypto_evict_key()`` must be called
+on each block_device.
 
 API presented to device drivers
 ===============================

block/blk-crypto.c

@@ -386,20 +386,6 @@ bool blk_crypto_config_supported_natively(struct block_device *bdev,
 	return true;
 }
 
-/*
- * Check if bios with @cfg can be en/decrypted by blk-crypto (i.e. either the
- * block_device it's submitted to supports inline crypto, or the
- * blk-crypto-fallback is enabled and supports the cfg).
- */
-bool blk_crypto_config_supported(struct block_device *bdev,
-				 const struct blk_crypto_config *cfg)
-{
-	if (IS_ENABLED(CONFIG_BLK_INLINE_ENCRYPTION_FALLBACK) &&
-	    cfg->key_type == BLK_CRYPTO_KEY_TYPE_RAW)
-		return true;
-	return blk_crypto_config_supported_natively(bdev, cfg);
-}
-
 /**
  * blk_crypto_start_using_key() - Start using a blk_crypto_key on a device
  * @bdev: block device to operate on

include/linux/blk-crypto.h

@@ -171,8 +171,6 @@ void blk_crypto_evict_key(struct block_device *bdev,
 
 bool blk_crypto_config_supported_natively(struct block_device *bdev,
 					  const struct blk_crypto_config *cfg);
-bool blk_crypto_config_supported(struct block_device *bdev,
-				 const struct blk_crypto_config *cfg);
 
 int blk_crypto_derive_sw_secret(struct block_device *bdev,
 				const u8 *eph_key, size_t eph_key_size,