lightnvm: pblk: gc all lines in the pipeline before exit

Finish garbage collect of the lines that are in the gc pipeline
before exiting. Ensure that all lines already in in the pipeline
goes through, from read to write.

Do this by keeping track of how many lines are in the pipeline
and waiting for that number to reach zero before exiting the gc
reader task.

Since we're adding a new gc line counter, change the name of
inflight_gc to read_inflight_gc to make the distinction clear.

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>

1 files changed, 24 insertions, 7 deletions

diff --git a/drivers/lightnvm/pblk-gc.c b/drivers/lightnvm/pblk-gc.c
index e00e5a0743e9..e6fae1959e25 100644
--- a/drivers/lightnvm/pblk-gc.c
+++ b/drivers/lightnvm/pblk-gc.c
@@ -234,7 +234,7 @@ out:
 	kfree(invalid_bitmap);
 
 	kref_put(&line->ref, pblk_line_put);
-	atomic_dec(&gc->inflight_gc);
+	atomic_dec(&gc->read_inflight_gc);
 
 	return;
 
@@ -249,7 +249,7 @@ fail_free_ws:
 
 	pblk_put_line_back(pblk, line);
 	kref_put(&line->ref, pblk_line_put);
-	atomic_dec(&gc->inflight_gc);
+	atomic_dec(&gc->read_inflight_gc);
 
 	pr_err("pblk: Failed to GC line %d\n", line->id);
 }
@@ -268,6 +268,7 @@ static int pblk_gc_line(struct pblk *pblk, struct pblk_line *line)
 	line_ws->pblk = pblk;
 	line_ws->line = line;
 
+	atomic_inc(&gc->pipeline_gc);
 	INIT_WORK(&line_ws->ws, pblk_gc_line_prepare_ws);
 	queue_work(gc->gc_reader_wq, &line_ws->ws);
 
@@ -333,6 +334,7 @@ static bool pblk_gc_should_run(struct pblk_gc *gc, struct pblk_rl *rl)
 void pblk_gc_free_full_lines(struct pblk *pblk)
 {
 	struct pblk_line_mgmt *l_mg = &pblk->l_mg;
+	struct pblk_gc *gc = &pblk->gc;
 	struct pblk_line *line;
 
 	do {
@@ -353,6 +355,7 @@ void pblk_gc_free_full_lines(struct pblk *pblk)
 		list_del(&line->list);
 		spin_unlock(&l_mg->gc_lock);
 
+		atomic_inc(&gc->pipeline_gc);
 		kref_put(&line->ref, pblk_line_put);
 	} while (1);
 }
@@ -370,12 +373,12 @@ static void pblk_gc_run(struct pblk *pblk)
 	struct pblk_line *line;
 	struct list_head *group_list;
 	bool run_gc;
-	int inflight_gc, gc_group = 0, prev_group = 0;
+	int read_inflight_gc, gc_group = 0, prev_group = 0;
 
 	pblk_gc_free_full_lines(pblk);
 
 	run_gc = pblk_gc_should_run(&pblk->gc, &pblk->rl);
-	if (!run_gc || (atomic_read(&gc->inflight_gc) >= PBLK_GC_L_QD))
+	if (!run_gc || (atomic_read(&gc->read_inflight_gc) >= PBLK_GC_L_QD))
 		return;
 
 next_gc_group:
@@ -402,14 +405,14 @@ next_gc_group:
 		list_add_tail(&line->list, &gc->r_list);
 		spin_unlock(&gc->r_lock);
 
-		inflight_gc = atomic_inc_return(&gc->inflight_gc);
+		read_inflight_gc = atomic_inc_return(&gc->read_inflight_gc);
 		pblk_gc_reader_kick(gc);
 
 		prev_group = 1;
 
 		/* No need to queue up more GC lines than we can handle */
 		run_gc = pblk_gc_should_run(&pblk->gc, &pblk->rl);
-		if (!run_gc || inflight_gc >= PBLK_GC_L_QD)
+		if (!run_gc || read_inflight_gc >= PBLK_GC_L_QD)
 			break;
 	} while (1);
 
@@ -470,6 +473,7 @@ static int pblk_gc_writer_ts(void *data)
 static int pblk_gc_reader_ts(void *data)
 {
 	struct pblk *pblk = data;
+	struct pblk_gc *gc = &pblk->gc;
 
 	while (!kthread_should_stop()) {
 		if (!pblk_gc_read(pblk))
@@ -478,6 +482,18 @@ static int pblk_gc_reader_ts(void *data)
 		io_schedule();
 	}
 
+#ifdef CONFIG_NVM_DEBUG
+	pr_info("pblk: flushing gc pipeline, %d lines left\n",
+		atomic_read(&gc->pipeline_gc));
+#endif
+
+	do {
+		if (!atomic_read(&gc->pipeline_gc))
+			break;
+
+		schedule();
+	} while (1);
+
 	return 0;
 }
 
@@ -586,7 +602,8 @@ int pblk_gc_init(struct pblk *pblk)
 	gc->gc_forced = 0;
 	gc->gc_enabled = 1;
 	gc->w_entries = 0;
-	atomic_set(&gc->inflight_gc, 0);
+	atomic_set(&gc->read_inflight_gc, 0);
+	atomic_set(&gc->pipeline_gc, 0);
 
 	/* Workqueue that reads valid sectors from a line and submit them to the
 	 * GC writer to be recycled.