#include "super-io.h"
 
 #include <linux/crc32c.h>
-#include <linux/crypto.h>
 #include <linux/xxhash.h>
 #include <linux/key.h>
 #include <linux/random.h>
 #include <linux/ratelimit.h>
-#include <linux/scatterlist.h>
-#include <crypto/algapi.h>
 #include <crypto/chacha.h>
-#include <crypto/hash.h>
 #include <crypto/poly1305.h>
-#include <crypto/skcipher.h>
 #include <keys/user-type.h>
 
 /*
        }
 }
 
-static inline int do_encrypt_sg(struct crypto_sync_skcipher *tfm,
-                               struct nonce nonce,
-                               struct scatterlist *sg, size_t len)
+static void bch2_chacha20_init(u32 state[CHACHA_STATE_WORDS],
+                              const struct bch_key *key, struct nonce nonce)
 {
-       SYNC_SKCIPHER_REQUEST_ON_STACK(req, tfm);
+       u32 key_words[CHACHA_KEY_SIZE / sizeof(u32)];
 
-       skcipher_request_set_sync_tfm(req, tfm);
-       skcipher_request_set_callback(req, 0, NULL, NULL);
-       skcipher_request_set_crypt(req, sg, sg, len, nonce.d);
+       BUILD_BUG_ON(sizeof(key_words) != sizeof(*key));
+       memcpy(key_words, key, sizeof(key_words));
+       le32_to_cpu_array(key_words, ARRAY_SIZE(key_words));
 
-       int ret = crypto_skcipher_encrypt(req);
-       if (ret)
-               pr_err("got error %i from crypto_skcipher_encrypt()", ret);
-
-       return ret;
-}
-
-static inline int do_encrypt(struct crypto_sync_skcipher *tfm,
-                             struct nonce nonce,
-                             void *buf, size_t len)
-{
-       if (!is_vmalloc_addr(buf)) {
-               struct scatterlist sg = {};
-
-               sg_mark_end(&sg);
-               sg_set_page(&sg, virt_to_page(buf), len, offset_in_page(buf));
-               return do_encrypt_sg(tfm, nonce, &sg, len);
-       } else {
-               DARRAY_PREALLOCATED(struct scatterlist, 4) sgl;
-               size_t sgl_len = 0;
-               int ret;
-
-               darray_init(&sgl);
-
-               while (len) {
-                       unsigned offset = offset_in_page(buf);
-                       struct scatterlist sg = {
-                               .page_link      = (unsigned long) vmalloc_to_page(buf),
-                               .offset         = offset,
-                               .length         = min(len, PAGE_SIZE - offset),
-                       };
+       BUILD_BUG_ON(sizeof(nonce) != CHACHA_IV_SIZE);
+       chacha_init(state, key_words, (const u8 *)nonce.d);
 
-                       if (darray_push(&sgl, sg)) {
-                               sg_mark_end(&darray_last(sgl));
-                               ret = do_encrypt_sg(tfm, nonce, sgl.data, sgl_len);
-                               if (ret)
-                                       goto err;
-
-                               nonce = nonce_add(nonce, sgl_len);
-                               sgl_len = 0;
-                               sgl.nr = 0;
-                               BUG_ON(darray_push(&sgl, sg));
-                       }
-
-                       buf += sg.length;
-                       len -= sg.length;
-                       sgl_len += sg.length;
-               }
-
-               sg_mark_end(&darray_last(sgl));
-               ret = do_encrypt_sg(tfm, nonce, sgl.data, sgl_len);
-err:
-               darray_exit(&sgl);
-               return ret;
-       }
+       memzero_explicit(key_words, sizeof(key_words));
 }
 
-int bch2_chacha_encrypt_key(struct bch_key *key, struct nonce nonce,
-                           void *buf, size_t len)
+static void bch2_chacha20(const struct bch_key *key, struct nonce nonce,
+                         void *data, size_t len)
 {
-       struct crypto_sync_skcipher *chacha20 =
-               crypto_alloc_sync_skcipher("chacha20", 0, 0);
-       int ret;
-
-       ret = PTR_ERR_OR_ZERO(chacha20);
-       if (ret) {
-               pr_err("error requesting chacha20 cipher: %s", bch2_err_str(ret));
-               return ret;
-       }
-
-       ret = crypto_skcipher_setkey(&chacha20->base,
-                                    (void *) key, sizeof(*key));
-       if (ret) {
-               pr_err("error from crypto_skcipher_setkey(): %s", bch2_err_str(ret));
-               goto err;
-       }
+       u32 state[CHACHA_STATE_WORDS];
 
-       ret = do_encrypt(chacha20, nonce, buf, len);
-err:
-       crypto_free_sync_skcipher(chacha20);
-       return ret;
+       bch2_chacha20_init(state, key, nonce);
+       chacha20_crypt(state, data, data, len);
+       memzero_explicit(state, sizeof(state));
 }
 
-static int gen_poly_key(struct bch_fs *c, struct shash_desc *desc,
-                       struct nonce nonce)
+static void bch2_poly1305_init(struct poly1305_desc_ctx *desc,
+                              struct bch_fs *c, struct nonce nonce)
 {
-       u8 key[POLY1305_KEY_SIZE];
-       int ret;
+       u8 key[POLY1305_KEY_SIZE] = { 0 };
 
        nonce.d[3] ^= BCH_NONCE_POLY;
 
-       memset(key, 0, sizeof(key));
-       ret = do_encrypt(c->chacha20, nonce, key, sizeof(key));
-       if (ret)
-               return ret;
-
-       desc->tfm = c->poly1305;
-       crypto_shash_init(desc);
-       crypto_shash_update(desc, key, sizeof(key));
-       return 0;
+       bch2_chacha20(&c->chacha20_key, nonce, key, sizeof(key));
+       poly1305_init(desc, key);
 }
 
 struct bch_csum bch2_checksum(struct bch_fs *c, unsigned type,
 
        case BCH_CSUM_chacha20_poly1305_80:
        case BCH_CSUM_chacha20_poly1305_128: {
-               SHASH_DESC_ON_STACK(desc, c->poly1305);
+               struct poly1305_desc_ctx dctx;
                u8 digest[POLY1305_DIGEST_SIZE];
                struct bch_csum ret = { 0 };
 
-               gen_poly_key(c, desc, nonce);
-
-               crypto_shash_update(desc, data, len);
-               crypto_shash_final(desc, digest);
+               bch2_poly1305_init(&dctx, c, nonce);
+               poly1305_update(&dctx, data, len);
+               poly1305_final(&dctx, digest);
 
                memcpy(&ret, digest, bch_crc_bytes[type]);
                return ret;
        if (!bch2_csum_type_is_encryption(type))
                return 0;
 
-       if (bch2_fs_inconsistent_on(!c->chacha20,
+       if (bch2_fs_inconsistent_on(!c->chacha20_key_set,
                                    c, "attempting to encrypt without encryption key"))
                return -BCH_ERR_no_encryption_key;
 
-       return do_encrypt(c->chacha20, nonce, data, len);
+       bch2_chacha20(&c->chacha20_key, nonce, data, len);
+       return 0;
 }
 
 static struct bch_csum __bch2_checksum_bio(struct bch_fs *c, unsigned type,
 
        case BCH_CSUM_chacha20_poly1305_80:
        case BCH_CSUM_chacha20_poly1305_128: {
-               SHASH_DESC_ON_STACK(desc, c->poly1305);
+               struct poly1305_desc_ctx dctx;
                u8 digest[POLY1305_DIGEST_SIZE];
                struct bch_csum ret = { 0 };
 
-               gen_poly_key(c, desc, nonce);
+               bch2_poly1305_init(&dctx, c, nonce);
 
 #ifdef CONFIG_HIGHMEM
                __bio_for_each_segment(bv, bio, *iter, *iter) {
                        void *p = kmap_local_page(bv.bv_page) + bv.bv_offset;
 
-                       crypto_shash_update(desc, p, bv.bv_len);
+                       poly1305_update(&dctx, p, bv.bv_len);
                        kunmap_local(p);
                }
 #else
                __bio_for_each_bvec(bv, bio, *iter, *iter)
-                       crypto_shash_update(desc,
+                       poly1305_update(&dctx,
                                page_address(bv.bv_page) + bv.bv_offset,
                                bv.bv_len);
 #endif
-               crypto_shash_final(desc, digest);
+               poly1305_final(&dctx, digest);
 
                memcpy(&ret, digest, bch_crc_bytes[type]);
                return ret;
 {
        struct bio_vec bv;
        struct bvec_iter iter;
-       DARRAY_PREALLOCATED(struct scatterlist, 4) sgl;
-       size_t sgl_len = 0;
+       u32 chacha_state[CHACHA_STATE_WORDS];
        int ret = 0;
 
-       if (bch2_fs_inconsistent_on(!c->chacha20,
+       if (bch2_fs_inconsistent_on(!c->chacha20_key_set,
                                    c, "attempting to encrypt without encryption key"))
                return -BCH_ERR_no_encryption_key;
 
-       darray_init(&sgl);
+       bch2_chacha20_init(chacha_state, &c->chacha20_key, nonce);
 
        bio_for_each_segment(bv, bio, iter) {
-               struct scatterlist sg = {
-                       .page_link      = (unsigned long) bv.bv_page,
-                       .offset         = bv.bv_offset,
-                       .length         = bv.bv_len,
-               };
-
-               if (darray_push(&sgl, sg)) {
-                       sg_mark_end(&darray_last(sgl));
-                       ret = do_encrypt_sg(c->chacha20, nonce, sgl.data, sgl_len);
-                       if (ret)
-                               goto err;
-
-                       nonce = nonce_add(nonce, sgl_len);
-                       sgl_len = 0;
-                       sgl.nr = 0;
-
-                       BUG_ON(darray_push(&sgl, sg));
+               void *p;
+
+               /*
+                * chacha_crypt() assumes that the length is a multiple of
+                * CHACHA_BLOCK_SIZE on any non-final call.
+                */
+               if (!IS_ALIGNED(bv.bv_len, CHACHA_BLOCK_SIZE)) {
+                       bch_err_ratelimited(c, "bio not aligned for encryption");
+                       ret = -EIO;
+                       break;
                }
 
-               sgl_len += sg.length;
+               p = bvec_kmap_local(&bv);
+               chacha20_crypt(chacha_state, p, p, bv.bv_len);
+               kunmap_local(p);
        }
-
-       sg_mark_end(&darray_last(sgl));
-       ret = do_encrypt_sg(c->chacha20, nonce, sgl.data, sgl_len);
-err:
-       darray_exit(&sgl);
+       memzero_explicit(chacha_state, sizeof(chacha_state));
        return ret;
 }
 
        }
 
        /* decrypt real key: */
-       ret = bch2_chacha_encrypt_key(&user_key, bch2_sb_key_nonce(c),
-                                     &sb_key, sizeof(sb_key));
-       if (ret)
-               goto err;
+       bch2_chacha20(&user_key, bch2_sb_key_nonce(c), &sb_key, sizeof(sb_key));
 
        if (bch2_key_is_encrypted(&sb_key)) {
                bch_err(c, "incorrect encryption key");
        return ret;
 }
 
-static int bch2_alloc_ciphers(struct bch_fs *c)
-{
-       if (c->chacha20)
-               return 0;
-
-       struct crypto_sync_skcipher *chacha20 = crypto_alloc_sync_skcipher("chacha20", 0, 0);
-       int ret = PTR_ERR_OR_ZERO(chacha20);
-       if (ret) {
-               bch_err(c, "error requesting chacha20 module: %s", bch2_err_str(ret));
-               return ret;
-       }
-
-       struct crypto_shash *poly1305 = crypto_alloc_shash("poly1305", 0, 0);
-       ret = PTR_ERR_OR_ZERO(poly1305);
-       if (ret) {
-               bch_err(c, "error requesting poly1305 module: %s", bch2_err_str(ret));
-               crypto_free_sync_skcipher(chacha20);
-               return ret;
-       }
-
-       c->chacha20     = chacha20;
-       c->poly1305     = poly1305;
-       return 0;
-}
-
 #if 0
 
 /*
 
 void bch2_fs_encryption_exit(struct bch_fs *c)
 {
-       if (c->poly1305)
-               crypto_free_shash(c->poly1305);
-       if (c->chacha20)
-               crypto_free_sync_skcipher(c->chacha20);
+       memzero_explicit(&c->chacha20_key, sizeof(c->chacha20_key));
 }
 
 int bch2_fs_encryption_init(struct bch_fs *c)
 {
        struct bch_sb_field_crypt *crypt;
-       struct bch_key key;
-       int ret = 0;
+       int ret;
 
        crypt = bch2_sb_field_get(c->disk_sb.sb, crypt);
        if (!crypt)
-               goto out;
+               return 0;
 
-       ret = bch2_alloc_ciphers(c);
+       ret = bch2_decrypt_sb_key(c, crypt, &c->chacha20_key);
        if (ret)
-               goto out;
-
-       ret = bch2_decrypt_sb_key(c, crypt, &key);
-       if (ret)
-               goto out;
-
-       ret = crypto_skcipher_setkey(&c->chacha20->base,
-                       (void *) &key.key, sizeof(key.key));
-       if (ret)
-               goto out;
-out:
-       memzero_explicit(&key, sizeof(key));
-       return ret;
+               return ret;
+       c->chacha20_key_set = true;
+       return 0;
 }