[PATCH v3] f2fs: deliver the accumulated 'issued' to __issue_discard_cmd_orderly() to meet the max_requests limit

[Yuwei Guan]

Any of the following scenarios will send more than the number of
max_requests at a time, which will not meet the design of the
max_requests limit.

- Set max_ordered_discard larger than discard_granularity from userspace.
- It is a small size device, discard_granularity can be tuned to 1 in
  f2fs_tuning_parameters().

We need to deliver the accumulated @issued to __issue_discard_cmd_orderly()
to meet the max_requests limit.

BTW, convert the parameter type of @issued in __submit_discard_cmd().

Signed-off-by: Yuwei Guan <Yuwei.Guan@xxxxxxxxxxxxx>
Cc: Bagas Sanjaya <bagasdotme@xxxxxxxxx>
---
 fs/f2fs/segment.c | 24 +++++++++++-------------
 1 file changed, 11 insertions(+), 13 deletions(-)

diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index a9099a754dd2..5268938466f5 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -1097,8 +1097,7 @@ static void __update_discard_tree_range(struct f2fs_sb_info *sbi,
 /* this function is copied from blkdev_issue_discard from block/blk-lib.c */
 static int __submit_discard_cmd(struct f2fs_sb_info *sbi,
 						struct discard_policy *dpolicy,
-						struct discard_cmd *dc,
-						unsigned int *issued)
+						struct discard_cmd *dc, int *issued)
 {
 	struct block_device *bdev = dc->bdev;
 	unsigned int max_discard_blocks =
@@ -1379,8 +1378,8 @@ static void __queue_discard_cmd(struct f2fs_sb_info *sbi,
 	mutex_unlock(&SM_I(sbi)->dcc_info->cmd_lock);
 }
 
-static unsigned int __issue_discard_cmd_orderly(struct f2fs_sb_info *sbi,
-					struct discard_policy *dpolicy)
+static void __issue_discard_cmd_orderly(struct f2fs_sb_info *sbi,
+					struct discard_policy *dpolicy, int *issued)
 {
 	struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
 	struct discard_cmd *prev_dc = NULL, *next_dc = NULL;
@@ -1388,7 +1387,6 @@ static unsigned int __issue_discard_cmd_orderly(struct f2fs_sb_info *sbi,
 	struct discard_cmd *dc;
 	struct blk_plug plug;
 	unsigned int pos = dcc->next_pos;
-	unsigned int issued = 0;
 	bool io_interrupted = false;
 
 	mutex_lock(&dcc->cmd_lock);
@@ -1415,9 +1413,9 @@ static unsigned int __issue_discard_cmd_orderly(struct f2fs_sb_info *sbi,
 		}
 
 		dcc->next_pos = dc->lstart + dc->len;
-		err = __submit_discard_cmd(sbi, dpolicy, dc, &issued);
+		err = __submit_discard_cmd(sbi, dpolicy, dc, issued);
 
-		if (issued >= dpolicy->max_requests)
+		if (*issued >= dpolicy->max_requests)
 			break;
 next:
 		node = rb_next(&dc->rb_node);
@@ -1433,10 +1431,8 @@ static unsigned int __issue_discard_cmd_orderly(struct f2fs_sb_info *sbi,
 
 	mutex_unlock(&dcc->cmd_lock);
 
-	if (!issued && io_interrupted)
-		issued = -1;
-
-	return issued;
+	if (!(*issued) && io_interrupted)
+		*issued = -1;
 }
 static unsigned int __wait_all_discard_cmd(struct f2fs_sb_info *sbi,
 					struct discard_policy *dpolicy);
@@ -1464,8 +1460,10 @@ static int __issue_discard_cmd(struct f2fs_sb_info *sbi,
 		if (i + 1 < dpolicy->granularity)
 			break;
 
-		if (i + 1 < dcc->max_ordered_discard && dpolicy->ordered)
-			return __issue_discard_cmd_orderly(sbi, dpolicy);
+		if (i + 1 < dcc->max_ordered_discard && dpolicy->ordered) {
+			__issue_discard_cmd_orderly(sbi, dpolicy, &issued);
+			return issued;
+		}
 
 		pend_list = &dcc->pend_list[i];
 
-- 
2.34.1