lightnvm: pblk: start gc if needed during init

Start GC if needed, directly after init, as we might
need to garbage collect in order to make room for user writes.

Create a helper function that allows to kick GC without exposing the
internals of the GC/rate-limiter interaction.
Signed-off-by: Hans Holmberg <hans.holmberg@cnexlabs.com>
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

drivers/lightnvm/pblk-gc.c

@@ -510,6 +510,11 @@ void pblk_gc_should_stop(struct pblk *pblk)
 		pblk_gc_stop(pblk, 0);
 }
 
+void pblk_gc_should_kick(struct pblk *pblk)
+{
+	pblk_rl_update_rates(&pblk->rl);
+}
+
 void pblk_gc_sysfs_state_show(struct pblk *pblk, int *gc_enabled,
 			      int *gc_active)
 {

drivers/lightnvm/pblk-init.c

@@ -1025,6 +1025,10 @@ static void *pblk_init(struct nvm_tgt_dev *dev, struct gendisk *tdisk,
 			pblk->rwb.nr_entries);
 
 	wake_up_process(pblk->writer_ts);
+
+	/* Check if we need to start GC */
+	pblk_gc_should_kick(pblk);
+
 	return pblk;
 
 fail_stop_writer:

drivers/lightnvm/pblk-rl.c

@@ -96,7 +96,7 @@ unsigned long pblk_rl_nr_free_blks(struct pblk_rl *rl)
  *
  * Only the total number of free blocks is used to configure the rate limiter.
  */
-static void pblk_rl_update_rates(struct pblk_rl *rl)
+void pblk_rl_update_rates(struct pblk_rl *rl)
 {
 	struct pblk *pblk = container_of(rl, struct pblk, rl);
 	unsigned long free_blocks = pblk_rl_nr_free_blks(rl);

drivers/lightnvm/pblk.h

@@ -830,6 +830,7 @@ int pblk_gc_init(struct pblk *pblk);
 void pblk_gc_exit(struct pblk *pblk);
 void pblk_gc_should_start(struct pblk *pblk);
 void pblk_gc_should_stop(struct pblk *pblk);
+void pblk_gc_should_kick(struct pblk *pblk);
 void pblk_gc_kick(struct pblk *pblk);
 void pblk_gc_free_full_lines(struct pblk *pblk);
 void pblk_gc_sysfs_state_show(struct pblk *pblk, int *gc_enabled,
@@ -841,6 +842,7 @@ int pblk_gc_sysfs_force(struct pblk *pblk, int force);
  */
 void pblk_rl_init(struct pblk_rl *rl, int budget);
 void pblk_rl_free(struct pblk_rl *rl);
+void pblk_rl_update_rates(struct pblk_rl *rl);
 int pblk_rl_high_thrs(struct pblk_rl *rl);
 int pblk_rl_low_thrs(struct pblk_rl *rl);
 unsigned long pblk_rl_nr_free_blks(struct pblk_rl *rl);