Re: [PATCH V2] lightnvm: pblk: fix mapping issue on failed writes

From: Hans Holmberg
Date: Mon Sep 03 2018 - 03:57:06 EST


On Fri, Aug 31, 2018 at 4:18 PM Matias BjÃrling <mb@xxxxxxxxxxx> wrote:
>
> On 08/31/2018 11:59 AM, Hans Holmberg wrote:
> > From: Hans Holmberg <hans.holmberg@xxxxxxxxxxxx>
> >
> > On 1.2-devices, the mapping-out of remaning sectors in the
> > failed-write's block can result in an infinite loop,
> > stalling the write pipeline, fix this.
> >
> > Fixes: 6a3abf5beef6 ("lightnvm: pblk: rework write error recovery path")
> >
> > Signed-off-by: Hans Holmberg <hans.holmberg@xxxxxxxxxxxx>
> > ---
> >
> > Changes in V2:
> > Moved the helper function pblk_next_ppa_in_blk to lightnvm core
> > Renamed variable done->last in the helper function
> >
> >
> > drivers/lightnvm/pblk-write.c | 10 +---------
> > include/linux/lightnvm.h | 34 ++++++++++++++++++++++++++++++++++
> > 2 files changed, 35 insertions(+), 9 deletions(-)
> >
> > diff --git a/drivers/lightnvm/pblk-write.c b/drivers/lightnvm/pblk-write.c
> > index 5e6df65d392c..922506d2d0a6 100644
> > --- a/drivers/lightnvm/pblk-write.c
> > +++ b/drivers/lightnvm/pblk-write.c
> > @@ -125,15 +125,7 @@ static void pblk_map_remaining(struct pblk *pblk, struct ppa_addr *ppa)
> > if (!test_and_set_bit(paddr, line->invalid_bitmap))
> > le32_add_cpu(line->vsc, -1);
> >
> > - if (geo->version == NVM_OCSSD_SPEC_12) {
> > - map_ppa.ppa++;
> > - if (map_ppa.g.pg == geo->num_pg)
> > - done = 1;
> > - } else {
> > - map_ppa.m.sec++;
> > - if (map_ppa.m.sec == geo->clba)
> > - done = 1;
> > - }
> > + done = nvm_next_ppa_in_blk(geo, &map_ppa);
> > }
> >
> > line->w_err_gc->has_write_err = 1;
> > diff --git a/include/linux/lightnvm.h b/include/linux/lightnvm.h
> > index 09f65c6c6676..2a6cbfe1d1b4 100644
> > --- a/include/linux/lightnvm.h
> > +++ b/include/linux/lightnvm.h
> > @@ -593,6 +593,40 @@ static inline u32 nvm_ppa64_to_ppa32(struct nvm_dev *dev,
> > return ppa32;
> > }
> >
> > +static inline int nvm_next_ppa_in_blk(struct nvm_geo *geo, struct ppa_addr *ppa)
>
> You can pass nvm_tgt_dev here. Then the two unfoldings in
> pblk_map_remaining are not needed.

Yeah. thats better. fixed.

>
> The naming sounds very 1.2ish, how about nvm_get_next_lba_in_chk?

I used blk because in the generic ppa format (ppa_addr.a), the name is blk.
Chunk is more abstract concept so i think it's better using that going forward.
Fixed.

>
> > +{
> > + int last = 0;
> > +
> > + if (geo->version == NVM_OCSSD_SPEC_12) {
> > + int sec = ppa->g.sec;
> > +
> > + sec++;
> > + if (sec == geo->ws_min) {
> > + int pg = ppa->g.pg;
> > +
> > + sec = 0;
> > + pg++;
> > + if (pg == geo->num_pg) {
> > + int pl = ppa->g.pl;
> > +
> > + pg = 0;
> > + pl++;
> > + if (pl == geo->num_pln)
> > + last = 1;
> > +
> > + ppa->g.pl = pl;
> > + }
> > + ppa->g.pg = pg;
> > + }
> > + ppa->g.sec = sec;
> > + } else {
> > + ppa->m.sec++;
> > + if (ppa->m.sec == geo->clba)
> > + last = 1;
> > + }
> > +
> > + return last;
> > +}
> >
> > typedef blk_qc_t (nvm_tgt_make_rq_fn)(struct request_queue *, struct bio *);
> > typedef sector_t (nvm_tgt_capacity_fn)(void *);
> >
>