[PATCH] efi_loader: Set EFI_SIMPLE_NETWORK_RECEIVE_INTERRUPT again in efi_net_receive()

[Heinrich Schuchardt]

On 9/14/21 4:06 AM, Masami Hiramatsu wrote:
> From: Kazuhiko Sakamoto <sakamoto.kazuhiko at socionext.com>
>
> Since 'this->int_status' is cleared by efi_net_get_status(), if user

Is it correct to clear int_status unconditionally in efi_net_get_status()?

Shouldn't two consecutive calls to EFI_SIMPLE_NETWORK.GetStatus() return
the same result?

Best regards

Heinrich

> does wait_for_event(wait_for_packet) and efi_net_get_status() loop
> and there are several received packets on the buffer, the second
> efi_net_get_status() does not return EFI_SIMPLE_NETWORK_RECEIVE_INTERRUPT
> even if the 'wait_for_packet' is ready.
>
> This happens on "efiboot selftest" with noisy network.
> (The network device can receive both of other packets and dhcp discover
>   packet in a short time.)
>
> Set EFI_SIMPLE_NETWORK_RECEIVE_INTERRUPT again when we found any
> packet still on the receive buffer.
>
> Signed-off-by: Kazuhiko Sakamoto <sakamoto.kazuhiko at socionext.com>
> Signed-off-by: Masami Hiramatsu <masami.hiramatsu at linaro.org>
> ---
>   lib/efi_loader/efi_net.c |   13 +++++++++++--
>   1 file changed, 11 insertions(+), 2 deletions(-)
>
> diff --git a/lib/efi_loader/efi_net.c b/lib/efi_loader/efi_net.c
> index 69276b275d..9ca1e0c354 100644
> --- a/lib/efi_loader/efi_net.c
> +++ b/lib/efi_loader/efi_net.c
> @@ -640,10 +640,19 @@ static efi_status_t EFIAPI efi_net_receive
>   	*buffer_size = receive_lengths[rx_packet_idx];
>   	rx_packet_idx = (rx_packet_idx + 1) % ETH_PACKETS_BATCH_RECV;
>   	rx_packet_num--;
> -	if (rx_packet_num)
> +	if (rx_packet_num) {
> +		/*
> +		 * Since 'this->int_status' is cleared by efi_net_get_status(),
> +		 * if user does wait_for_event(wait_for_packet) and
> +		 * efi_net_get_status() again, EFI_SIMPLE_NETWORK_RECEIVE_INTERRUPT
> +		 * is not set even if 'wait_for_packet' is ready.
> +		 * Set EFI_SIMPLE_NETWORK_RECEIVE_INTERRUPT again here.
> +		 */
> +		this->int_status |= EFI_SIMPLE_NETWORK_RECEIVE_INTERRUPT;
>   		wait_for_packet->is_signaled = true;
> -	else
> +	} else {
>   		this->int_status &= ~EFI_SIMPLE_NETWORK_RECEIVE_INTERRUPT;
> +	}
>   out:
>   	return EFI_EXIT(ret);
>   }
>