[RFC v3 2/2] pmem: enable pmem_submit_bio for asynchronous flush

[Pankaj Gupta]

Return from "pmem_submit_bio" when asynchronous flush is
still in progress in other context.

Signed-off-by: Pankaj Gupta <pankaj.gupta.li...@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 */
+               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;
        }
 
-- 
2.25.1