linux-kernel - [PATCH v2] w1: Replace usage of found with dedicated list iterator variable

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Date:   Wed, 10 May 2023 00:49:53 +0200
From:   Jakob Koschel <jkl820.git@...il.com>
To:     Evgeniy Polyakov <zbr@...emap.net>,
        Krzysztof Kozlowski <krzk@...nel.org>
Cc:     linux-kernel@...r.kernel.org, Jakob Koschel <jkl820.git@...il.com>
Subject: [PATCH v2] w1: 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/ [1]
Signed-off-by: Jakob Koschel <jkl820.git@...il.com>
---
Changes in v2:
  - fix checkpatch intentation issues

Note: I've changed my email address to contributions to
jkl820.git@...il.com, I hope that's not an issue since the v1 was still
on my old email.
---
 drivers/w1/w1.c | 32 +++++++++++++++-----------------
 1 file changed, 15 insertions(+), 17 deletions(-)

diff --git a/drivers/w1/w1.c b/drivers/w1/w1.c
index 9d199fed9628..c453160684e1 100644
--- a/drivers/w1/w1.c
+++ b/drivers/w1/w1.c
@@ -830,49 +830,47 @@ int w1_slave_detach(struct w1_slave *sl)
 
 struct w1_master *w1_search_master_id(u32 id)
 {
-	struct w1_master *dev;
-	int found = 0;
+	struct w1_master *dev = NULL, *iter;
 
 	mutex_lock(&w1_mlock);
-	list_for_each_entry(dev, &w1_masters, w1_master_entry) {
-		if (dev->id == id) {
-			found = 1;
-			atomic_inc(&dev->refcnt);
+	list_for_each_entry(iter, &w1_masters, w1_master_entry) {
+		if (iter->id == id) {
+			dev = iter;
+			atomic_inc(&iter->refcnt);
 			break;
 		}
 	}
 	mutex_unlock(&w1_mlock);
 
-	return (found)?dev:NULL;
+	return dev;
 }
 
 struct w1_slave *w1_search_slave(struct w1_reg_num *id)
 {
 	struct w1_master *dev;
-	struct w1_slave *sl = NULL;
-	int found = 0;
+	struct w1_slave *sl = NULL, *iter;
 
 	mutex_lock(&w1_mlock);
 	list_for_each_entry(dev, &w1_masters, w1_master_entry) {
 		mutex_lock(&dev->list_mutex);
-		list_for_each_entry(sl, &dev->slist, w1_slave_entry) {
-			if (sl->reg_num.family == id->family &&
-					sl->reg_num.id == id->id &&
-					sl->reg_num.crc == id->crc) {
-				found = 1;
+		list_for_each_entry(iter, &dev->slist, w1_slave_entry) {
+			if (iter->reg_num.family == id->family &&
+					iter->reg_num.id == id->id &&
+					iter->reg_num.crc == id->crc) {
+				sl = iter;
 				atomic_inc(&dev->refcnt);
-				atomic_inc(&sl->refcnt);
+				atomic_inc(&iter->refcnt);
 				break;
 			}
 		}
 		mutex_unlock(&dev->list_mutex);
 
-		if (found)
+		if (sl)
 			break;
 	}
 	mutex_unlock(&w1_mlock);
 
-	return (found)?sl:NULL;
+	return sl;
 }
 
 void w1_reconnect_slaves(struct w1_family *f, int attach)

---
base-commit: eeac8ede17557680855031c6f305ece2378af326
change-id: 20230509-w1-replace-usage-of-found-with-tmp-list-iterator-variable-c56393ff0339

Best regards,
-- 
Jakob Koschel <jkl820.git@...il.com>