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Date:   Thu, 16 May 2019 02:28:20 -0400 (EDT)
From:   Pankaj Gupta <pagupta@redhat.com>
To:     Dan Williams <dan.j.williams@intel.com>
Cc:     linux-nvdimm <linux-nvdimm@lists.01.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
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References: <20190514145422.16923-1-pagupta@redhat.com> <20190514145422.16923-2-pagupta@redhat.com> <CAPcyv4gEr_zPJEQp3k89v2UXfHp9PQwnJXY+W99HwXfxpvua_w@mail.gmail.com>
Subject: Re: [PATCH v9 1/7] libnvdimm: nd_region flush callback support
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Thread-Topic: libnvdimm: nd_region flush callback support
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> >
> > This patch adds functionality to perform flush from guest
> > to host over VIRTIO. We are registering a callback based
> > on 'nd_region' type. virtio_pmem driver requires this special
> > flush function. For rest of the region types we are registering
> > existing flush function. Report error returned by host fsync
> > failure to userspace.
> >
> > Signed-off-by: Pankaj Gupta <pagupta@redhat.com>
> > ---
> >  drivers/acpi/nfit/core.c     |  4 ++--
> >  drivers/nvdimm/claim.c       |  6 ++++--
> >  drivers/nvdimm/nd.h          |  1 +
> >  drivers/nvdimm/pmem.c        | 13 ++++++++-----
> >  drivers/nvdimm/region_devs.c | 26 ++++++++++++++++++++++++--
> >  include/linux/libnvdimm.h    |  8 +++++++-
> >  6 files changed, 46 insertions(+), 12 deletions(-)
> >
> > diff --git a/drivers/acpi/nfit/core.c b/drivers/acpi/nfit/core.c
> > index 5a389a4f4f65..08dde76cf459 100644
> > --- a/drivers/acpi/nfit/core.c
> > +++ b/drivers/acpi/nfit/core.c
> > @@ -2434,7 +2434,7 @@ static void write_blk_ctl(struct nfit_blk *nfit_blk,
> > unsigned int bw,
> >                 offset = to_interleave_offset(offset, mmio);
> >
> >         writeq(cmd, mmio->addr.base + offset);
> > -       nvdimm_flush(nfit_blk->nd_region);
> > +       nvdimm_flush(nfit_blk->nd_region, NULL);
> >
> >         if (nfit_blk->dimm_flags & NFIT_BLK_DCR_LATCH)
> >                 readq(mmio->addr.base + offset);
> > @@ -2483,7 +2483,7 @@ static int acpi_nfit_blk_single_io(struct nfit_blk
> > *nfit_blk,
> >         }
> >
> >         if (rw)
> > -               nvdimm_flush(nfit_blk->nd_region);
> > +               nvdimm_flush(nfit_blk->nd_region, NULL);
> >
> >         rc = read_blk_stat(nfit_blk, lane) ? -EIO : 0;
> >         return rc;
> > diff --git a/drivers/nvdimm/claim.c b/drivers/nvdimm/claim.c
> > index fb667bf469c7..13510bae1e6f 100644
> > --- a/drivers/nvdimm/claim.c
> > +++ b/drivers/nvdimm/claim.c
> > @@ -263,7 +263,7 @@ static int nsio_rw_bytes(struct nd_namespace_common
> > *ndns,
> >         struct nd_namespace_io *nsio = to_nd_namespace_io(&ndns->dev);
> >         unsigned int sz_align = ALIGN(size + (offset & (512 - 1)), 512);
> >         sector_t sector = offset >> 9;
> > -       int rc = 0;
> > +       int rc = 0, ret = 0;
> >
> >         if (unlikely(!size))
> >                 return 0;
> > @@ -301,7 +301,9 @@ static int nsio_rw_bytes(struct nd_namespace_common
> > *ndns,
> >         }
> >
> >         memcpy_flushcache(nsio->addr + offset, buf, size);
> > -       nvdimm_flush(to_nd_region(ndns->dev.parent));
> > +       ret = nvdimm_flush(to_nd_region(ndns->dev.parent), NULL);
> > +       if (ret)
> > +               rc = ret;
> >
> >         return rc;
> >  }
> > diff --git a/drivers/nvdimm/nd.h b/drivers/nvdimm/nd.h
> > index a5ac3b240293..0c74d2428bd7 100644
> > --- a/drivers/nvdimm/nd.h
> > +++ b/drivers/nvdimm/nd.h
> > @@ -159,6 +159,7 @@ struct nd_region {
> >         struct badblocks bb;
> >         struct nd_interleave_set *nd_set;
> >         struct nd_percpu_lane __percpu *lane;
> > +       int (*flush)(struct nd_region *nd_region, struct bio *bio);
> 
> So this triggers:
> 
> In file included from drivers/nvdimm/e820.c:7:
> ./include/linux/libnvdimm.h:140:51: warning: ‘struct bio’ declared
> inside parameter list will not be visible outside of this definition
> or declaration
>   int (*flush)(struct nd_region *nd_region, struct bio *bio);
>                                                    ^~~

Sorry! for this. Fixed now.

> I was already feeling uneasy about trying to squeeze this into v5.2,
> but this warning and the continued drip of comments leads me to
> conclude that this driver would do well to wait one more development
> cycle. Lets close out the final fixups and let this driver soak in
> -next. Then for the v5.3 cycle I'll redouble my efforts towards the
> goal of closing patch acceptance at the -rc6 / -rc7 development
> milestone.

o.k. Will wait for Mike's ACK on device mapper patch and send the v10
with final fix-ups. Thank you for your help.

Best regards,
Pankaj


>