[PATCH] char: misc: remove usage of list iterator past the loop body

From: Jakob Koschel
Date: Sat Mar 19 2022 - 16:15:30 EST


In preparation to limit the scope of the list iterator to the list
traversal loop, use a dedicated pointer pointing to the found element [1].

Link: https://lore.kernel.org/all/YhdfEIwI4EdtHdym@xxxxxxxxx/
Signed-off-by: Jakob Koschel <jakobkoschel@xxxxxxxxx>
---
drivers/char/misc.c | 24 +++++++++++++-----------
1 file changed, 13 insertions(+), 11 deletions(-)

diff --git a/drivers/char/misc.c b/drivers/char/misc.c
index ca5141ed5ef3..cba19bfdc44d 100644
--- a/drivers/char/misc.c
+++ b/drivers/char/misc.c
@@ -100,17 +100,18 @@ static const struct seq_operations misc_seq_ops = {
static int misc_open(struct inode *inode, struct file *file)
{
int minor = iminor(inode);
- struct miscdevice *c;
+ struct miscdevice *c = NULL, *iter;
int err = -ENODEV;
const struct file_operations *new_fops = NULL;

mutex_lock(&misc_mtx);

- list_for_each_entry(c, &misc_list, list) {
- if (c->minor == minor) {
- new_fops = fops_get(c->fops);
- break;
- }
+ list_for_each_entry(iter, &misc_list, list) {
+ if (iter->minor != minor)
+ continue;
+ c = iter;
+ new_fops = fops_get(iter->fops);
+ break;
}

if (!new_fops) {
@@ -118,11 +119,12 @@ static int misc_open(struct inode *inode, struct file *file)
request_module("char-major-%d-%d", MISC_MAJOR, minor);
mutex_lock(&misc_mtx);

- list_for_each_entry(c, &misc_list, list) {
- if (c->minor == minor) {
- new_fops = fops_get(c->fops);
- break;
- }
+ list_for_each_entry(iter, &misc_list, list) {
+ if (iter->minor != minor)
+ continue;
+ c = iter;
+ new_fops = fops_get(iter->fops);
+ break;
}
if (!new_fops)
goto fail;

base-commit: 34e047aa16c0123bbae8e2f6df33e5ecc1f56601
--
2.25.1