[PATCH 4.12 105/196] f2fs: try to freeze in gc and discard threads

[Greg Kroah-Hartman]

4.12-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Jaegeuk Kim <jaegeuk@xxxxxxxxxx>

commit 1d7be2708277edfef95171d52fb65ee26eaa076b upstream.

This allows to freeze gc and discard threads.

Signed-off-by: Jaegeuk Kim <jaegeuk@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 fs/f2fs/gc.c      |    9 +++++----
 fs/f2fs/segment.c |   25 ++++++++++++++++---------
 2 files changed, 21 insertions(+), 13 deletions(-)

--- a/fs/f2fs/gc.c
+++ b/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 {
+		wait_event_interruptible_timeout(*wq,
+				kthread_should_stop() || freezing(current),
+				msecs_to_jiffies(wait_ms));
+
 		if (try_to_freeze())
 			continue;
-		else
-			wait_event_interruptible_timeout(*wq,
-						kthread_should_stop(),
-						msecs_to_jiffies(wait_ms));
 		if (kthread_should_stop())
 			break;
 
--- a/fs/f2fs/segment.c
+++ b/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"
@@ -1060,18 +1061,24 @@ static int issue_discard_thread(void *da
 	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:
-	if (kthread_should_stop())
-		return 0;
 
-	__issue_discard_cmd(sbi, true);
-	__wait_discard_cmd(sbi, true);
+	set_freezable();
 
-	congestion_wait(BLK_RW_SYNC, HZ/50);
+	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;
 
-	wait_event_interruptible(*q, kthread_should_stop() ||
-				atomic_read(&dcc->discard_cmd_cnt));
-	goto repeat;
+		__issue_discard_cmd(sbi, true);
+		__wait_discard_cmd(sbi, true);
+
+		congestion_wait(BLK_RW_SYNC, HZ/50);
+	} while (!kthread_should_stop());
+	return 0;
 }
 
 #ifdef CONFIG_BLK_DEV_ZONED