- * If the request_queue didn't support the key, then blk-crypto-fallback
- * may have been used, so try to evict the key from blk-crypto-fallback.
+ * An error can only occur here if the key failed to be evicted from a
+ * keyslot (due to a hardware or driver issue) or is allegedly still in
+ * use by I/O (due to a kernel bug). Even in these cases, the key is
+ * still unlinked from the keyslot management structures, and the caller
+ * is allowed and expected to free it right away. There's nothing
+ * callers can do to handle errors, so just log them and return void.