[dpdk-dev] [PATCH v3 2/5] eal: don't process IPC messages before init finished

[Wiles, Keith]

> 
> +	struct message_queue_entry *cur_msg, *next_msg, *new_msg = NULL;
> 	while (1) {
> -		if (read_msg(&msg, &sa) == 0)
> -			process_msg(&msg, &sa);
> +		/* we want to process all messages in order of their arrival,
> +		 * but status of init_complete may change while we're iterating
> +		 * the tailq. so, store it here and check once every iteration.
> +		 */
> +		int init_complete;

Do we allow variables to be defined in the middle of a block, I thought we only allowed them after a ‘{‘ or open block.

> +
> +		if (new_msg == NULL)
> +			new_msg = malloc(sizeof(*new_msg));

I am very concerned about allocating memory with no limit. If the process never completes then we could receive messages and consume a lot of memory. I would want to see a limit to the number of messages we can consume in the queue just to be sure.

> +		if (read_msg(&new_msg->msg, &new_msg->sa) == 0) {
> +			/* we successfully read the message, so enqueue it */
> +			TAILQ_INSERT_TAIL(&message_queue, new_msg, next);
> +			new_msg = NULL;
> +		} /* reuse new_msg for next message if we couldn't read_msg */
> +
> +		init_complete = internal_config.init_complete;

Does the internal_config.init_complete need to be a volatile to make sure it is reread each time thru the loop?

> +
> +		/* tailq only accessed here, so no locking needed */
> +		TAILQ_FOREACH_SAFE(cur_msg, &message_queue, next, next_msg) {
> +			/* secondary process should not process any incoming
> +			 * requests until its initialization is complete, but
> +			 * it is allowed to process replies to its own queries.
> +			 */
> +			if (rte_eal_process_type() == RTE_PROC_SECONDARY &&
> +					!init_complete &&
> +					cur_msg->msg.type != MP_REP)
> +				continue;
> +
> +			TAILQ_REMOVE(&message_queue, cur_msg, next);
> +
> +			process_msg(&cur_msg->msg, &cur_msg->sa);
> +
> +			free(cur_msg);
> +		}
> 	}
> 
> 	return NULL;
> -- 
> 2.7.4

Regards,
Keith