lightnvm: pblk: kick writer on new flush points

Unless we kick the writer directly when setting a new flush point, the
user risks having to wait for up to one second (the default timeout for
the write thread to be kicked) for the IO to complete.

Signed-off-by: Hans Holmberg <hans.holmberg@cnexlabs.com>
Signed-off-by: Matias Bjørling <mb@lightnvm.io>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

1 files changed, 6 insertions, 4 deletions

diff --git a/drivers/lightnvm/pblk-cache.c b/drivers/lightnvm/pblk-cache.c
index 29a23111b31c..b1c6d7eb6115 100644
--- a/drivers/lightnvm/pblk-cache.c
+++ b/drivers/lightnvm/pblk-cache.c
@@ -44,13 +44,15 @@ retry:
                 goto out;
         }
 
-        if (unlikely(!bio_has_data(bio)))
-                goto out;
-
         pblk_ppa_set_empty(&w_ctx.ppa);
         w_ctx.flags = flags;
-        if (bio->bi_opf & REQ_PREFLUSH)
+        if (bio->bi_opf & REQ_PREFLUSH) {
                 w_ctx.flags |= PBLK_FLUSH_ENTRY;
+                pblk_write_kick(pblk);
+        }
+
+        if (unlikely(!bio_has_data(bio)))
+                goto out;
 
         for (i = 0; i < nr_entries; i++) {
                 void *data = bio_data(bio);