lightnvm: pblk: simplify path on REQ_PREFLUSH
On REQ_PREFLUSH, directly tag the I/O context flags to signal a flush in
the write to cache path, instead of finding the correct entry context
and imposing a memory barrier. This simplifies the code and might
potentially prevent race conditions when adding functionality to the
write path.
Signed-off-by: Javier González <javier@cnexlabs.com>
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/drivers/lightnvm/pblk-rb.c b/drivers/lightnvm/pblk-rb.c
index 74c768c..05e6b2e 100644
--- a/drivers/lightnvm/pblk-rb.c
+++ b/drivers/lightnvm/pblk-rb.c
@@ -355,7 +355,6 @@ static int pblk_rb_sync_point_set(struct pblk_rb *rb, struct bio *bio,
{
struct pblk_rb_entry *entry;
unsigned int subm, sync_point;
- int flags;
subm = READ_ONCE(rb->subm);
@@ -369,12 +368,6 @@ static int pblk_rb_sync_point_set(struct pblk_rb *rb, struct bio *bio,
sync_point = (pos == 0) ? (rb->nr_entries - 1) : (pos - 1);
entry = &rb->entries[sync_point];
- flags = READ_ONCE(entry->w_ctx.flags);
- flags |= PBLK_FLUSH_ENTRY;
-
- /* Release flags on context. Protect from writes */
- smp_store_release(&entry->w_ctx.flags, flags);
-
/* Protect syncs */
smp_store_release(&rb->sync_point, sync_point);
@@ -454,6 +447,7 @@ static int pblk_rb_may_write_flush(struct pblk_rb *rb, unsigned int nr_entries,
/* Protect from read count */
smp_store_release(&rb->mem, mem);
+
return 1;
}