This is a note to let you know that I've just added the patch titled
ax25: Use kernel universal linked list to implement ax25_dev_list
to the 6.6-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
ax25-use-kernel-universal-linked-list-to-implement-a.patch
and it can be found in the queue-6.6 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 7bfd826f87b78462a5764d0d3b030a4ee40673f9
Author: Duoming Zhou <duoming@xxxxxxxxxx>
Date: Thu May 9 17:36:33 2024 +0800
ax25: Use kernel universal linked list to implement ax25_dev_list
[ Upstream commit a7d6e36b9ad052926ba2ecba3a59d8bb67dabcb4 ]
The origin ax25_dev_list implements its own single linked list,
which is complicated and error-prone. For example, when deleting
the node of ax25_dev_list in ax25_dev_device_down(), we have to
operate on the head node and other nodes separately.
This patch uses kernel universal linked list to replace original
ax25_dev_list, which make the operation of ax25_dev_list easier.
We should do "dev->ax25_ptr = ax25_dev;" and "dev->ax25_ptr = NULL;"
while holding the spinlock, otherwise the ax25_dev_device_up() and
ax25_dev_device_down() could race.
Suggested-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Signed-off-by: Duoming Zhou <duoming@xxxxxxxxxx>
Reviewed-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Link: https://lore.kernel.org/r/85bba3af651ca0e1a519da8d0d715b949891171c.1715247018.git.duoming@xxxxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Stable-dep-of: b505e0319852 ("ax25: Fix reference count leak issues of ax25_dev")
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/include/net/ax25.h b/include/net/ax25.h
index 0d939e5aee4ec..c2a85fd3f5ea4 100644
--- a/include/net/ax25.h
+++ b/include/net/ax25.h
@@ -216,7 +216,7 @@ typedef struct {
struct ctl_table;
typedef struct ax25_dev {
- struct ax25_dev *next;
+ struct list_head list;
struct net_device *dev;
netdevice_tracker dev_tracker;
@@ -330,7 +330,6 @@ int ax25_addr_size(const ax25_digi *);
void ax25_digi_invert(const ax25_digi *, ax25_digi *);
/* ax25_dev.c */
-extern ax25_dev *ax25_dev_list;
extern spinlock_t ax25_dev_lock;
#if IS_ENABLED(CONFIG_AX25)
diff --git a/net/ax25/ax25_dev.c b/net/ax25/ax25_dev.c
index 282ec581c0720..f16ee5c09d07a 100644
--- a/net/ax25/ax25_dev.c
+++ b/net/ax25/ax25_dev.c
@@ -22,11 +22,12 @@
#include <net/sock.h>
#include <linux/uaccess.h>
#include <linux/fcntl.h>
+#include <linux/list.h>
#include <linux/mm.h>
#include <linux/interrupt.h>
#include <linux/init.h>
-ax25_dev *ax25_dev_list;
+static LIST_HEAD(ax25_dev_list);
DEFINE_SPINLOCK(ax25_dev_lock);
ax25_dev *ax25_addr_ax25dev(ax25_address *addr)
@@ -34,7 +35,7 @@ ax25_dev *ax25_addr_ax25dev(ax25_address *addr)
ax25_dev *ax25_dev, *res = NULL;
spin_lock_bh(&ax25_dev_lock);
- for (ax25_dev = ax25_dev_list; ax25_dev != NULL; ax25_dev = ax25_dev->next)
+ list_for_each_entry(ax25_dev, &ax25_dev_list, list)
if (ax25cmp(addr, (const ax25_address *)ax25_dev->dev->dev_addr) == 0) {
res = ax25_dev;
ax25_dev_hold(ax25_dev);
@@ -59,7 +60,6 @@ void ax25_dev_device_up(struct net_device *dev)
}
refcount_set(&ax25_dev->refcount, 1);
- dev->ax25_ptr = ax25_dev;
ax25_dev->dev = dev;
netdev_hold(dev, &ax25_dev->dev_tracker, GFP_KERNEL);
ax25_dev->forward = NULL;
@@ -85,8 +85,8 @@ void ax25_dev_device_up(struct net_device *dev)
#endif
spin_lock_bh(&ax25_dev_lock);
- ax25_dev->next = ax25_dev_list;
- ax25_dev_list = ax25_dev;
+ list_add(&ax25_dev->list, &ax25_dev_list);
+ dev->ax25_ptr = ax25_dev;
spin_unlock_bh(&ax25_dev_lock);
ax25_dev_hold(ax25_dev);
@@ -111,32 +111,25 @@ void ax25_dev_device_down(struct net_device *dev)
/*
* Remove any packet forwarding that points to this device.
*/
- for (s = ax25_dev_list; s != NULL; s = s->next)
+ list_for_each_entry(s, &ax25_dev_list, list)
if (s->forward == dev)
s->forward = NULL;
- if ((s = ax25_dev_list) == ax25_dev) {
- ax25_dev_list = s->next;
- goto unlock_put;
- }
-
- while (s != NULL && s->next != NULL) {
- if (s->next == ax25_dev) {
- s->next = ax25_dev->next;
+ list_for_each_entry(s, &ax25_dev_list, list) {
+ if (s == ax25_dev) {
+ list_del(&s->list);
goto unlock_put;
}
-
- s = s->next;
}
- spin_unlock_bh(&ax25_dev_lock);
dev->ax25_ptr = NULL;
+ spin_unlock_bh(&ax25_dev_lock);
ax25_dev_put(ax25_dev);
return;
unlock_put:
+ dev->ax25_ptr = NULL;
spin_unlock_bh(&ax25_dev_lock);
ax25_dev_put(ax25_dev);
- dev->ax25_ptr = NULL;
netdev_put(dev, &ax25_dev->dev_tracker);
ax25_dev_put(ax25_dev);
}
@@ -200,16 +193,13 @@ struct net_device *ax25_fwd_dev(struct net_device *dev)
*/
void __exit ax25_dev_free(void)
{
- ax25_dev *s, *ax25_dev;
+ ax25_dev *s, *n;
spin_lock_bh(&ax25_dev_lock);
- ax25_dev = ax25_dev_list;
- while (ax25_dev != NULL) {
- s = ax25_dev;
- netdev_put(ax25_dev->dev, &ax25_dev->dev_tracker);
- ax25_dev = ax25_dev->next;
+ list_for_each_entry_safe(s, n, &ax25_dev_list, list) {
+ netdev_put(s->dev, &s->dev_tracker);
+ list_del(&s->list);
kfree(s);
}
- ax25_dev_list = NULL;
spin_unlock_bh(&ax25_dev_lock);
}
