[PATCH v2] mailbox: mtk-cmdq: fix runtime PM usage counter leak in cmdq_mbox_flush

[PATCH v2] mailbox: mtk-cmdq: fix runtime PM usage counter leak in cmdq_mbox_flush

[Manush Prajwal]

cmdq_mbox_flush() calls pm_runtime_get_sync() and returns its error
code directly on failure. Per Documentation/power/runtime_pm.rst,
pm_runtime_get_sync() does not drop the usage counter on error, so the
caller is expected to release the reference itself. The early return
here skips that, leaking a runtime PM usage count on cmdq->mbox.dev on
every failed resume.

Fix it by switching to pm_runtime_resume_and_get(), which performs the
get-and-put internally on failure so the caller doesn't need a manual
pm_runtime_put_noidle(), per Markus Elfring's review of v1.

Signed-off-by: Manush Prajwal <manushprajwal555@gmail.com>
---
v2: Use pm_runtime_resume_and_get() instead of pm_runtime_get_sync()
    plus a manual pm_runtime_put_noidle() on the error path, per
    Markus Elfring's review.

 drivers/mailbox/mtk-cmdq-mailbox.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/mailbox/mtk-cmdq-mailbox.c b/drivers/mailbox/mtk-cmdq-mailbox.c
index e523c84b4..b1a2c3d4e 100644
--- a/drivers/mailbox/mtk-cmdq-mailbox.c
+++ b/drivers/mailbox/mtk-cmdq-mailbox.c
@@ -565,7 +565,7 @@ static int cmdq_mbox_flush(struct mbox_chan *chan, unsigned long timeout)
 	int ret;

-	ret = pm_runtime_get_sync(cmdq->mbox.dev);
+	ret = pm_runtime_resume_and_get(cmdq->mbox.dev);
 	if (ret < 0)
 		return ret;

--
2.46.2.windows.1