[PATCH] f2fs: continuous counting for 'issued' in __issue_discard_cmd_orderly()

[Yuwei Guan]

As the 'dcc->discard_granularity' and 'dcc->max_ordered_discard' can be set
at the user space, and if the 'dcc->max_ordered_discard' is set larger than
'dcc->discard_granularity' in DPOLICY_BG mode, or it's a volume device,
discard_granularity can be tuned to 1 in f2fs_tuning_parameters(),
it will may send more requests than the number of 'dpolicy->max_requests'
in issue_discard_thread().

This patch will fix the issue.

Signed-off-by: Yuwei Guan <Yuwei.Guan@xxxxxxxxxxxxx>
---
 fs/f2fs/segment.c | 17 ++++++++---------
 1 file changed, 8 insertions(+), 9 deletions(-)

diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index 8b0b76550578..b0157bf392fb 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -1379,8 +1379,8 @@ static int __queue_discard_cmd(struct f2fs_sb_info *sbi,
 	return 0;
 }
 
-static unsigned int __issue_discard_cmd_orderly(struct f2fs_sb_info *sbi,
-					struct discard_policy *dpolicy)
+static int __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 +1388,6 @@ 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 +1414,9 @@ 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 +1432,10 @@ static unsigned int __issue_discard_cmd_orderly(struct f2fs_sb_info *sbi,
 
 	mutex_unlock(&dcc->cmd_lock);
 
-	if (!issued && io_interrupted)
-		issued = -1;
+	if (!(*issued) && io_interrupted)
+		*issued = -1;
 
-	return issued;
+	return *issued;
 }
 static unsigned int __wait_all_discard_cmd(struct f2fs_sb_info *sbi,
 					struct discard_policy *dpolicy);
@@ -1465,7 +1464,7 @@ static int __issue_discard_cmd(struct f2fs_sb_info *sbi,
 			break;
 
 		if (i + 1 < dcc->max_ordered_discard && dpolicy->ordered)
-			return __issue_discard_cmd_orderly(sbi, dpolicy);
+			return __issue_discard_cmd_orderly(sbi, dpolicy, &issued);
 
 		pend_list = &dcc->pend_list[i];
 
-- 
2.34.1