blk_crypto_fallback_keyslot
struct blk_crypto_fallback_keyslot *slotp = &blk_crypto_keyslots[slot];
const struct blk_crypto_fallback_keyslot *slotp =
struct blk_crypto_fallback_keyslot *slotp;
struct blk_crypto_fallback_keyslot *slotp = &blk_crypto_keyslots[slot];