lightnvm: pblk: use constant for GC max inflight

Use a constant to set the maximum number of inflight GC requests
allowed.

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-gc.c b/drivers/lightnvm/pblk-gc.c
index f163829..c21b207 100644
--- a/drivers/lightnvm/pblk-gc.c
+++ b/drivers/lightnvm/pblk-gc.c
@@ -93,7 +93,7 @@ static int pblk_gc_move_valid_secs(struct pblk *pblk, struct pblk_gc_rq *gc_rq)
 
 retry:
 	spin_lock(&gc->w_lock);
-	if (gc->w_entries >= PBLK_GC_W_QD) {
+	if (gc->w_entries >= PBLK_GC_RQ_QD) {
 		spin_unlock(&gc->w_lock);
 		pblk_gc_writer_kick(&pblk->gc);
 		usleep_range(128, 256);
@@ -602,7 +602,7 @@ int pblk_gc_init(struct pblk *pblk)
 	spin_lock_init(&gc->w_lock);
 	spin_lock_init(&gc->r_lock);
 
-	sema_init(&gc->gc_sem, 128);
+	sema_init(&gc->gc_sem, PBLK_GC_RQ_QD);
 
 	INIT_LIST_HEAD(&gc->w_list);
 	INIT_LIST_HEAD(&gc->r_list);