linux-kernel - [PATCH 2/2] f2fs: replace usage of found with dedicated list iterator variable

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Date:   Fri,  1 Apr 2022 00:16:50 +0200
From:   Jakob Koschel <jakobkoschel@...il.com>
To:     Jaegeuk Kim <jaegeuk@...nel.org>
Cc:     Chao Yu <chao@...nel.org>, linux-f2fs-devel@...ts.sourceforge.net,
        linux-kernel@...r.kernel.org, Mike Rapoport <rppt@...nel.org>,
        "Brian Johannesmeyer" <bjohannesmeyer@...il.com>,
        Cristiano Giuffrida <c.giuffrida@...nl>,
        "Bos, H.J." <h.j.bos@...nl>, Jakob Koschel <jakobkoschel@...il.com>
Subject: [PATCH 2/2] f2fs: replace usage of found with dedicated list iterator variable

To move the list iterator variable into the list_for_each_entry_*()
macro in the future it should be avoided to use the list iterator
variable after the loop body.

To *never* use the list iterator variable after the loop it was
concluded to use a separate iterator variable instead of a
found boolean [1].

This removes the need to use a found variable and simply checking if
the variable was set, can determine if the break/goto was hit.

Link: https://lore.kernel.org/all/CAHk-=wgRr_D8CB-D9Kg-c=EHreAsk5SqXPwr9Y7k9sA6cWXJ6w@mail.gmail.com/
Signed-off-by: Jakob Koschel <jakobkoschel@...il.com>
---
 fs/f2fs/segment.c | 27 +++++++++++++--------------
 1 file changed, 13 insertions(+), 14 deletions(-)

diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index 81ef2c3d08e5..037164bf40a6 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -1666,33 +1666,32 @@ static unsigned int __wait_discard_cmd_range(struct f2fs_sb_info *sbi,
 	struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
 	struct list_head *wait_list = (dpolicy->type == DPOLICY_FSTRIM) ?
 					&(dcc->fstrim_list) : &(dcc->wait_list);
-	struct discard_cmd *dc, *tmp;
-	bool need_wait;
+	struct discard_cmd *dc = NULL, *iter, *tmp;
 	unsigned int trimmed = 0;
 
 next:
-	need_wait = false;
+	dc = NULL;
 
 	mutex_lock(&dcc->cmd_lock);
-	list_for_each_entry_safe(dc, tmp, wait_list, list) {
-		if (dc->lstart + dc->len <= start || end <= dc->lstart)
+	list_for_each_entry_safe(iter, tmp, wait_list, list) {
+		if (iter->lstart + iter->len <= start || end <= iter->lstart)
 			continue;
-		if (dc->len < dpolicy->granularity)
+		if (iter->len < dpolicy->granularity)
 			continue;
-		if (dc->state == D_DONE && !dc->ref) {
-			wait_for_completion_io(&dc->wait);
-			if (!dc->error)
-				trimmed += dc->len;
-			__remove_discard_cmd(sbi, dc);
+		if (iter->state == D_DONE && !iter->ref) {
+			wait_for_completion_io(&iter->wait);
+			if (!iter->error)
+				trimmed += iter->len;
+			__remove_discard_cmd(sbi, iter);
 		} else {
-			dc->ref++;
-			need_wait = true;
+			iter->ref++;
+			dc = iter;
 			break;
 		}
 	}
 	mutex_unlock(&dcc->cmd_lock);
 
-	if (need_wait) {
+	if (dc) {
 		trimmed += __wait_one_discard_bio(sbi, dc);
 		goto next;
 	}
-- 
2.25.1