Dan Williams
2022-Feb-16 16:25 UTC
[RFC v3 2/2] pmem: enable pmem_submit_bio for asynchronous flush
On Wed, Feb 16, 2022 at 12:39 AM Pankaj Gupta <pankaj.gupta.linux at gmail.com> wrote:> > > > > > > Return from "pmem_submit_bio" when asynchronous flush is > > > still in progress in other context. > > > > > > Signed-off-by: Pankaj Gupta <pankaj.gupta.linux at 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?Ok, maybe a comment to indicate the need to avoid exposing these error codes toa guest so someone does not ask the same question in the future?