Re: [GIT PULL 24/25] lightnvm: pblk: add iostat support

[Matias BjÃrling]

On 01/05/2018 04:42 PM, Jens Axboe wrote:
> On Fri, Jan 05 2018, Matias Bjørling wrote:
> > From: Javier González <javier@xxxxxxxxxxxx>
> >
> > Since pblk registers its own block device, the iostat accounting is
> > not automatically done for us. Therefore, add the necessary
> > accounting logic to satisfy the iostat interface.
>
> Ignorant question - why is it a raw block device, not using blk-mq?

The current flow is using the raw block device, together with the blk-mq 
nvme device driver. A bio is sent down to the nvme_nvm_submit_io() path 
in the /drivers/nvme/host/lightnvm.c file. From there it attaches the to 
NVMe blk-mq implementation.

Is there a better way to do it?

> > @@ -193,9 +197,9 @@ static void pblk_end_io_read(struct nvm_rq *rqd)
> >  	__pblk_end_io_read(pblk, rqd, true);
> >  }
> >
> > -static int pblk_fill_partial_read_bio(struct pblk *pblk, struct nvm_rq *rqd,
> > -				      unsigned int bio_init_idx,
> > -				      unsigned long *read_bitmap)
> > +static int pblk_partial_read_bio(struct pblk *pblk, struct nvm_rq *rqd,
> > +				 unsigned int bio_init_idx,
> > +				 unsigned long *read_bitmap)
> >  {
> >  	struct bio *new_bio, *bio = rqd->bio;
> >  	struct pblk_sec_meta *meta_list = rqd->meta_list;
> > @@ -306,6 +310,8 @@ static int pblk_fill_partial_read_bio(struct pblk *pblk, struct nvm_rq *rqd,
> >  	return NVM_IO_OK;
> >
> >  err:
> > +	pr_err("pblk: failed to perform partial read\n");
> > +
> >  	/* Free allocated pages in new bio */
> >  	pblk_bio_free_pages(pblk, bio, 0, new_bio->bi_vcnt);
> >  	__pblk_end_io_read(pblk, rqd, false);
>
> This seems to include unrelated changes, like the rename above and the
> addition of the error logging?

Grah... I missed it during review. It should have been its own patch or 
part of the early refactor patches. Thanks for picking it up.