Hi Vakul,
Only minor comments, mostly looks good to me. Thanks
> +/* This function decrypts the input skb into either out_iov or in out_sg
> + * or in skb buffers itself. The input parameter 'zc' indicates if
> + * zero-copy mode needs to be tried or not. With zero-copy mode, either
> + * out_iov or out_sg must be non-NULL. In case both out_iov and out_sg are
> + * NULL, then the decryption happens inside skb buffers itself, i.e.
> + * zero-copy gets disabled and 'zc' is updated.
> + */
> +
> +static int decrypt_internal(struct sock *sk, struct sk_buff *skb,
> + struct iov_iter *out_iov,
> + struct scatterlist *out_sg,
> + int *chunk, bool *zc)
> +{
> + struct tls_context *tls_ctx = tls_get_ctx(sk);
> + struct tls_sw_context_rx *ctx = tls_sw_ctx_rx(tls_ctx);
> + struct strp_msg *rxm = strp_msg(skb);
> + int n_sgin, n_sgout, nsg, mem_size, aead_size, err, pages = 0;
> + struct aead_request *aead_req;
> + struct sk_buff *unused;
> + u8 *aad, *iv, *mem = NULL;
> + struct scatterlist *sgin = NULL;
> + struct scatterlist *sgout = NULL;
> + const int data_len = rxm->full_len - tls_ctx->rx.overhead_size;
> +
> + if (*zc && (out_iov || out_sg)) {
> + if (out_iov)
> + n_sgout = iov_iter_npages(out_iov, INT_MAX) + 1;
> + else if (out_sg)
> + n_sgout = sg_nents(out_sg);
> + else
> + goto no_zerocopy;
Is the last else necessary? It looks like the if already checks for
out_iov || out_sg.
> struct scatterlist *sgout)
> {
> - struct tls_context *tls_ctx = tls_get_ctx(sk);
> - struct tls_sw_context_rx *ctx = tls_sw_ctx_rx(tls_ctx);
> - char iv[TLS_CIPHER_AES_GCM_128_SALT_SIZE + MAX_IV_SIZE];
> - struct scatterlist sgin_arr[MAX_SKB_FRAGS + 2];
> - struct scatterlist *sgin = &sgin_arr[0];
> - struct strp_msg *rxm = strp_msg(skb);
> - int ret, nsg;
> - struct sk_buff *unused;
> -
> - ret = skb_copy_bits(skb, rxm->offset + TLS_HEADER_SIZE,
> - iv + TLS_CIPHER_AES_GCM_128_SALT_SIZE,
> - tls_ctx->rx.iv_size);
> - if (ret < 0)
> - return ret;
> -
> - memcpy(iv, tls_ctx->rx.iv, TLS_CIPHER_AES_GCM_128_SALT_SIZE);
> - if (!sgout) {
> - nsg = skb_cow_data(skb, 0, &unused);
> - } else {
> - nsg = skb_nsg(skb,
> - rxm->offset + tls_ctx->rx.prepend_size,
> - rxm->full_len - tls_ctx->rx.prepend_size);
> - if (nsg <= 0)
> - return nsg;
> - }
> -
> - // We need one extra for ctx->rx_aad_ciphertext
> - nsg++;
> -
> - if (nsg > ARRAY_SIZE(sgin_arr))
> - sgin = kmalloc_array(nsg, sizeof(*sgin), sk->sk_allocation);
> -
> - if (!sgout)
> - sgout = sgin;
> -
> - sg_init_table(sgin, nsg);
> - sg_set_buf(&sgin[0], ctx->rx_aad_ciphertext, TLS_AAD_SPACE_SIZE);
> -
> - nsg = skb_to_sgvec(skb, &sgin[1],
> - rxm->offset + tls_ctx->rx.prepend_size,
> - rxm->full_len - tls_ctx->rx.prepend_size);
> - if (nsg < 0) {
> - ret = nsg;
> - goto out;
> - }
> -
> - tls_make_aad(ctx->rx_aad_ciphertext,
> - rxm->full_len - tls_ctx->rx.overhead_size,
> - tls_ctx->rx.rec_seq,
> - tls_ctx->rx.rec_seq_size,
> - ctx->control);
> -
> - ret = tls_do_decryption(sk, sgin, sgout, iv,
> - rxm->full_len - tls_ctx->rx.overhead_size,
> - skb, sk->sk_allocation);
> -
> -out:
> - if (sgin != &sgin_arr[0])
> - kfree(sgin);
> + bool zc = true;
> + int chunk;
>
> - return ret;
> + return decrypt_internal(sk, skb, NULL, sgout, &chunk, &zc);
> }
Can we merge this function to callsites? It's pretty useless now.
>
> static bool tls_sw_advance_skb(struct sock *sk, struct sk_buff *skb,
> @@ -899,43 +964,17 @@ int tls_sw_recvmsg(struct sock *sk,
> }
>
> if (!ctx->decrypted) {
> - int page_count;
> - int to_copy;
