Re: [Qemu-devel] [PATCH] tap: minor code cleanup

[Markus Armbruster]

"Michael S. Tsirkin" <address@hidden> writes:

> remove a confusing comment.
> TAP_DEFAULT_SNDBUF 0 is later translated to INT_MAX, so
> let's set that value directly.
>
> Signed-off-by: Michael S. Tsirkin <address@hidden>
> ---
>  net/tap-linux.c |    7 +------
>  1 files changed, 1 insertions(+), 6 deletions(-)
>
> diff --git a/net/tap-linux.c b/net/tap-linux.c
> index 00f84d4..b8c0f3b 100644
> --- a/net/tap-linux.c
> +++ b/net/tap-linux.c
> @@ -84,13 +84,8 @@ int tap_open(char *ifname, int ifname_size, int *vnet_hdr, 
> int vnet_hdr_required
>   * Unfortunately when it's enabled, and packets are sent
>   * to other guests on the same host, the receiver
>   * can lock up the transmitter indefinitely.
> - *
> - * To avoid packet loss, sndbuf should be set to a value lower than the tx
> - * queue capacity of any destination network interface.
> - * Ethernet NICs generally have txqueuelen=1000, so 1Mb is
> - * a good value, given a 1500 byte MTU.
>   */
> -#define TAP_DEFAULT_SNDBUF 0
> +#define TAP_DEFAULT_SNDBUF INT_MAX
>  
>  int tap_set_sndbuf(int fd, QemuOpts *opts)
>  {

Can't comment on whether the comment should stay or go, but what about
tap_set_sndbuf()'s

    if (!sndbuf) {
        sndbuf = INT_MAX;
    }

Shouldn't that assign TAP_DEFAULT_SNDBUF now?