f2fs: try to freeze in gc and discard threads

This allows to freeze gc and discard threads.

Cc: stable@vger.kernel.org
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/gc.c

@@ -32,13 +32,14 @@ static int gc_thread_func(void *data)
 
 	wait_ms = gc_th->min_sleep_time;
 
+	set_freezable();
 	do {
-		if (try_to_freeze())
-			continue;
-		else
 		wait_event_interruptible_timeout(*wq,
-						kthread_should_stop(),
+				kthread_should_stop() || freezing(current),
 				msecs_to_jiffies(wait_ms));
+
+		if (try_to_freeze())
+			continue;
 		if (kthread_should_stop())
 			break;
 

fs/f2fs/segment.c

@@ -16,6 +16,7 @@
 #include <linux/kthread.h>
 #include <linux/swap.h>
 #include <linux/timer.h>
+#include <linux/freezer.h>
 
 #include "f2fs.h"
 #include "segment.h"
@@ -1059,7 +1060,15 @@ static int issue_discard_thread(void *data)
 	struct f2fs_sb_info *sbi = data;
 	struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
 	wait_queue_head_t *q = &dcc->discard_wait_queue;
-repeat:
+
+	set_freezable();
+
+	do {
+		wait_event_interruptible(*q, kthread_should_stop() ||
+					freezing(current) ||
+					atomic_read(&dcc->discard_cmd_cnt));
+		if (try_to_freeze())
+			continue;
 		if (kthread_should_stop())
 			return 0;
 
@@ -1067,10 +1076,8 @@ static int issue_discard_thread(void *data)
 		__wait_discard_cmd(sbi, true);
 
 		congestion_wait(BLK_RW_SYNC, HZ/50);
-
-	wait_event_interruptible(*q, kthread_should_stop() ||
-				atomic_read(&dcc->discard_cmd_cnt));
-	goto repeat;
+	} while (!kthread_should_stop());
+	return 0;
 }
 
 #ifdef CONFIG_BLK_DEV_ZONED