[dm-devel] [PATCH V2] blk-mq: introduce BLK_STS_DEV_RESOURCE

[Mike Snitzer]

On Tue, Jan 23 2018 at  9:27am -0500,
Ming Lei <ming.lei at redhat.com> wrote:

> Hello Martin,
> 
> On Tue, Jan 23, 2018 at 08:30:41AM -0500, Martin K. Petersen wrote:
> > 
> > Ming,
> > 
> > > + * Block layer and block driver specific status, which is ususally returnd
> >                                                                       ^^^^^^^
> > > + * from driver to block layer in IO path.
> > 
> > Given that the comment blurb is long and the flag not defined until
> > later, it is not entirely obvious that you are documenting
> > BLK_STS_DEV_RESOURCE. So please make that clear at the beginning of the
> > comment.
> 
> OK, how about the following document?
> 
> /*
>  * BLK_STS_DEV_RESOURC: Block layer and block driver specific status,
     ^^^^^^^^^^^^^^^^^^^ typo

>  * which is usually returned from driver to block layer in IO path.
>  *
>  * BLK_STS_DEV_RESOURCE is returned from driver to block layer if device
>  * related resource is run out of, but driver can guarantee that queue
>  * will be rerun in future for dispatching the current request when this
>  * resource is available.
>  *
>  * Difference with BLK_STS_RESOURCE:
>  * If driver isn't sure if the queue can be run again for dealing with the
>  * current request after this kind of resource is available, please return
>  * BLK_STS_SOURCE, for example, when memory allocation, DMA Mapping or other
     ^^^^^^^^^^^^^^ typo

>  * system resource allocation fails and IO can't be submitted to device,
>  * BLK_STS_RESOURCE should be used for avoiding IO hang.
>  */

In general the 2nd paragraph is one big run-on sentence.  Needs some
isolation.