[dpdk-stable] [PATCH 16.11] vhost-user: fix false negative in handling user messages

[Maxime Coquelin]

On 11/28/18 5:20 PM, Luca Boccassi wrote:
> vhost_user_msg_handler checks an accumulated return code before
> returning, and prints an error and returns -1 if it's non-zero.
> But some of the possible user messages cannot fail and thus do not
> set the variable, which might retain a previously set and unrelated
> value, causing unnecessary failures and error messages.
> 
> Reset the return code before use.
> 
> Fixes: 0ce9e73d1e8d ("vhost-user: drop connection on message handling failures")
> 
> Signed-off-by: Luca Boccassi <bluca at debian.org>
> ---
> Found this issue when testing with the Vyatta stuff, "ret" is set at
> the beginning of the function and never reset when the message is for example
> VHOST_USER_GET_FEATURES so there's a flurry of errors.
> 
>   lib/librte_vhost/vhost_user.c | 1 +
>   1 file changed, 1 insertion(+)
> 
> diff --git a/lib/librte_vhost/vhost_user.c b/lib/librte_vhost/vhost_user.c
> index 00872c868..618d413fe 100644
> --- a/lib/librte_vhost/vhost_user.c
> +++ b/lib/librte_vhost/vhost_user.c
> @@ -1087,6 +1087,7 @@ vhost_user_msg_handler(int vid, int fd)
>   
>   	}
>   
> +	ret = 0;
>   	switch (msg.request) {
>   	case VHOST_USER_GET_FEATURES:
>   		msg.payload.u64 = vhost_user_get_features();
> 

Reviewed-by: Maxime Coquelin <maxime.coquelin at redhat.com>

Thanks!
Maxime