Re: [PATCH v2] block: Limit number of items taken from the I/O scheduler in one go

[Christoph Hellwig]

On Fri, Apr 24, 2020 at 08:15:29AM +0200, Christoph Hellwig wrote:
> This is a weird loop.  I'd split the code betweem the again label and
> the run_again check here into a __blk_mq_sched_dispatch_requests
> helper, and then you can do:
> 
> 	if (__blk_mq_sched_dispatch_requests()) {
> 		if (__blk_mq_sched_dispatch_requests())
> 			blk_mq_run_hw_queue(hctx, true);
> 	}
> 
> here.  Preferably with ha good comment explaining the logic.

Also I wonder if inverting the return values in the lower level function
would make things a little more readable - a true return suggests
everything worked fine.  Alternative 0 for sucess and -EAGAIN for needs
a retry also would be pretty self-documenting.