From: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
To: Dan Williams <dan.j.williams@intel.com>
Cc: Linux NVDIMM <nvdimm@lists.linux.dev>,
virtualization@lists.linux-foundation.org,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
jmoyer <jmoyer@redhat.com>, Stefan Hajnoczi <stefanha@redhat.com>,
David Hildenbrand <david@redhat.com>,
"Michael S. Tsirkin" <mst@redhat.com>,
Cornelia Huck <cohuck@redhat.com>,
Vishal L Verma <vishal.l.verma@intel.com>,
Dave Jiang <dave.jiang@intel.com>,
"Weiny, Ira" <ira.weiny@intel.com>,
Pankaj Gupta <pankaj.gupta@ionos.com>
Subject: Re: [RFC v3 2/2] pmem: enable pmem_submit_bio for asynchronous flush
Date: Wed, 16 Feb 2022 09:39:09 +0100 [thread overview]
Message-ID: <CAM9Jb+iYXn+Diq-vou+_hXdxXLR9rEXm6GOsd2tZpAg9zXn1Fw@mail.gmail.com> (raw)
In-Reply-To: <CAPcyv4gM99M8Waw9uEZefvpK0BsTkjGznLxUOMcMkGpk6SuHyA@mail.gmail.com>
> >
> > Return from "pmem_submit_bio" when asynchronous flush is
> > still in progress in other context.
> >
> > Signed-off-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
> > ---
> > drivers/nvdimm/pmem.c | 15 ++++++++++++---
> > drivers/nvdimm/region_devs.c | 4 +++-
> > 2 files changed, 15 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
> > index fe7ece1534e1..f20e30277a68 100644
> > --- a/drivers/nvdimm/pmem.c
> > +++ b/drivers/nvdimm/pmem.c
> > @@ -201,8 +201,12 @@ static void pmem_submit_bio(struct bio *bio)
> > struct pmem_device *pmem = bio->bi_bdev->bd_disk->private_data;
> > struct nd_region *nd_region = to_region(pmem);
> >
> > - if (bio->bi_opf & REQ_PREFLUSH)
> > + if (bio->bi_opf & REQ_PREFLUSH) {
> > ret = nvdimm_flush(nd_region, bio);
> > + /* asynchronous flush completes in other context */
>
> I think a negative error code is a confusing way to capture the case
> of "bio successfully coalesced to previously pending flush request.
> Perhaps reserve negative codes for failure, 0 for synchronously
> completed, and > 0 for coalesced flush request.
Yes. I implemented this way previously, will revert it to. Thanks!
>
> > + if (ret == -EINPROGRESS)
> > + return;
> > + }
> >
> > do_acct = blk_queue_io_stat(bio->bi_bdev->bd_disk->queue);
> > if (do_acct)
> > @@ -222,13 +226,18 @@ static void pmem_submit_bio(struct bio *bio)
> > if (do_acct)
> > bio_end_io_acct(bio, start);
> >
> > - if (bio->bi_opf & REQ_FUA)
> > + if (bio->bi_opf & REQ_FUA) {
> > ret = nvdimm_flush(nd_region, bio);
> > + /* asynchronous flush completes in other context */
> > + if (ret == -EINPROGRESS)
> > + return;
> > + }
> >
> > if (ret)
> > bio->bi_status = errno_to_blk_status(ret);
> >
> > - bio_endio(bio);
> > + if (bio)
> > + bio_endio(bio);
> > }
> >
> > static int pmem_rw_page(struct block_device *bdev, sector_t sector,
> > diff --git a/drivers/nvdimm/region_devs.c b/drivers/nvdimm/region_devs.c
> > index 9ccf3d608799..8512d2eaed4e 100644
> > --- a/drivers/nvdimm/region_devs.c
> > +++ b/drivers/nvdimm/region_devs.c
> > @@ -1190,7 +1190,9 @@ int nvdimm_flush(struct nd_region *nd_region, struct bio *bio)
> > if (!nd_region->flush)
> > rc = generic_nvdimm_flush(nd_region);
> > else {
> > - if (nd_region->flush(nd_region, bio))
> > + rc = nd_region->flush(nd_region, bio);
> > + /* ongoing flush in other context */
> > + if (rc && rc != -EINPROGRESS)
> > rc = -EIO;
>
> Why change this to -EIO vs just let the error code through untranslated?
The reason was to be generic error code instead of returning host side
return codes to guest?
Thanks!
Pankaj
>
> > }
> >
> > --
> > 2.25.1
> >
> >
next prev parent reply other threads:[~2022-02-16 8:39 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-11 16:19 [RFC v3 0/2] virtio-pmem: Asynchronous flush Pankaj Gupta
2022-01-11 16:19 ` [RFC v3 1/2] virtio-pmem: Async virtio-pmem flush Pankaj Gupta
2022-02-16 3:21 ` Dan Williams
2022-02-16 8:47 ` Pankaj Gupta
2022-02-16 16:23 ` Dan Williams
2022-02-16 17:04 ` Pankaj Gupta
2022-01-11 16:19 ` [RFC v3 2/2] pmem: enable pmem_submit_bio for asynchronous flush Pankaj Gupta
2022-02-16 3:34 ` Dan Williams
2022-02-16 8:39 ` Pankaj Gupta [this message]
2022-02-16 16:25 ` Dan Williams
2022-02-16 17:01 ` Pankaj Gupta
2022-01-28 10:11 ` [RFC v3 0/2] virtio-pmem: Asynchronous flush Pankaj Gupta
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