[PATCH 6.6 064/567] mailbox: Use guard/scoped_guard for con_mutex

Greg Kroah-Hartman
2026-03-23T14:54:23Z

6.6-stable review patch. If anyone has any objections, please let me know.

------------------

From: Peng Fan <peng.fan@nxp.com>

[ Upstream commit 16da9a653c5bf5d97fb296420899fe9735aa9c3c ]

Use guard and scoped_guard for con_mutex to simplify code.

Signed-off-by: Peng Fan <peng.fan@nxp.com>
Signed-off-by: Jassi Brar <jassisinghbrar@gmail.com>
Stable-dep-of: fcd7f96c7836 ("mailbox: Prevent out-of-bounds access in fw_mbox_index_xlate()")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/mailbox/mailbox.c | 61 +++++++++++++++++----------------------
1 file changed, 26 insertions(+), 35 deletions(-)

diff --git a/drivers/mailbox/mailbox.c b/drivers/mailbox/mailbox.c
index 4c27de9514e55..7dcbca48d1a0f 100644
--- a/drivers/mailbox/mailbox.c
+++ b/drivers/mailbox/mailbox.c
@@ -6,6 +6,7 @@
* Author: Jassi Brar <jassisinghbrar@gmail.com>
*/

+#include <linux/cleanup.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/err.h>
@@ -370,13 +371,9 @@ static int __mbox_bind_client(struct mbox_chan *chan, struct mbox_client *cl)
*/
int mbox_bind_client(struct mbox_chan *chan, struct mbox_client *cl)
{
- int ret;
-
- mutex_lock(&con_mutex);
- ret = __mbox_bind_client(chan, cl);
- mutex_unlock(&con_mutex);
+ guard(mutex)(&con_mutex);

- return ret;
+ return __mbox_bind_client(chan, cl);
}
EXPORT_SYMBOL_GPL(mbox_bind_client);

@@ -417,28 +414,25 @@ struct mbox_chan *mbox_request_channel(struct mbox_client *cl, int index)
return ERR_PTR(ret);
}

- mutex_lock(&con_mutex);
+ scoped_guard(mutex, &con_mutex) {
+ chan = ERR_PTR(-EPROBE_DEFER);
+ list_for_each_entry(mbox, &mbox_cons, node)
+ if (mbox->dev->of_node == spec.np) {
+ chan = mbox->of_xlate(mbox, &spec);
+ if (!IS_ERR(chan))
+ break;
+ }

- chan = ERR_PTR(-EPROBE_DEFER);
- list_for_each_entry(mbox, &mbox_cons, node)
- if (mbox->dev->of_node == spec.np) {
- chan = mbox->of_xlate(mbox, &spec);
- if (!IS_ERR(chan))
- break;
- }
+ of_node_put(spec.np);

- of_node_put(spec.np);
+ if (IS_ERR(chan))
+ return chan;

- if (IS_ERR(chan)) {
- mutex_unlock(&con_mutex);
- return chan;
+ ret = __mbox_bind_client(chan, cl);
+ if (ret)
+ chan = ERR_PTR(ret);
}

- ret = __mbox_bind_client(chan, cl);
- if (ret)
- chan = ERR_PTR(ret);
-
- mutex_unlock(&con_mutex);
return chan;
}
EXPORT_SYMBOL_GPL(mbox_request_channel);
@@ -549,9 +543,8 @@ int mbox_controller_register(struct mbox_controller *mbox)
if (!mbox->of_xlate)
mbox->of_xlate = of_mbox_index_xlate;

- mutex_lock(&con_mutex);
- list_add_tail(&mbox->node, &mbox_cons);
- mutex_unlock(&con_mutex);
+ scoped_guard(mutex, &con_mutex)
+ list_add_tail(&mbox->node, &mbox_cons);

return 0;
}
@@ -568,17 +561,15 @@ void mbox_controller_unregister(struct mbox_controller *mbox)
if (!mbox)
return;

- mutex_lock(&con_mutex);
-
- list_del(&mbox->node);
+ scoped_guard(mutex, &con_mutex) {
+ list_del(&mbox->node);

- for (i = 0; i < mbox->num_chans; i++)
- mbox_free_channel(&mbox->chans[i]);
+ for (i = 0; i < mbox->num_chans; i++)
+ mbox_free_channel(&mbox->chans[i]);

- if (mbox->txdone_poll)
- hrtimer_cancel(&mbox->poll_hrt);
-
- mutex_unlock(&con_mutex);
+ if (mbox->txdone_poll)
+ hrtimer_cancel(&mbox->poll_hrt);
+ }
}
EXPORT_SYMBOL_GPL(mbox_controller_unregister);

--
2.51.0