Re: [dpdk-dev] [PATCH v4 01/19] vhost: fix messages error checks

[Tiwei Bie <tiwei.bie@intel.com>]

On Mon, Oct 08, 2018 at 05:25:39PM +0200, Maxime Coquelin wrote:
> Return of message handling has now changed to an enum that can
> take non-negative value that is not zero in case a reply is
> needed. But the code checking the variable afterwards has not
> been updated, leading to success messages handling being
> treated as errors.
> 
> Fixes: 2f270595c05d ("vhost: rework message handling as a callback array")

Fixline should be:
Fixes: 0bff510b5ea6 ("vhost: unify message handling function signature")

> 
> Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
> Acked-by: Ilya Maximets <i.maximets@samsung.com>
> ---
>  lib/librte_vhost/vhost_user.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/lib/librte_vhost/vhost_user.c b/lib/librte_vhost/vhost_user.c
> index 7ef3fb4a4..060b41893 100644
> --- a/lib/librte_vhost/vhost_user.c
> +++ b/lib/librte_vhost/vhost_user.c
> @@ -1783,7 +1783,7 @@ vhost_user_msg_handler(int vid, int fd)
>  	}
>  
>  skip_to_post_handle:
> -	if (!ret && dev->extern_ops.post_msg_handle) {
> +	if (ret != VH_RESULT_ERR && dev->extern_ops.post_msg_handle) {
>  		uint32_t need_reply;
>  
>  		ret = (*dev->extern_ops.post_msg_handle)(
> @@ -1800,10 +1800,10 @@ vhost_user_msg_handler(int vid, int fd)
>  		vhost_user_unlock_all_queue_pairs(dev);
>  
>  	if (msg.flags & VHOST_USER_NEED_REPLY) {
> -		msg.payload.u64 = !!ret;
> +		msg.payload.u64 = ret == VH_RESULT_ERR;
>  		msg.size = sizeof(msg.payload.u64);
>  		send_vhost_reply(fd, &msg);
> -	} else if (ret) {
> +	} else if (ret == VH_RESULT_ERR) {
>  		RTE_LOG(ERR, VHOST_CONFIG,
>  			"vhost message handling failed.\n");
>  		return -1;

We also need to take care of the return value of .pre_msg_handle()
and .post_msg_handle(). Otherwise, errors could be ignored.

> -- 
> 2.17.1
>