[PATCH 2/4] Input: psmouse - clean up locking around disable_work_sync()

In the past, psmouse_disconnect() used cancel_work_sync(). Because
cancel_work_sync() must be called with the psmouse_mutex dropped, and we
needed to prevent psmouse_receive_byte() from re-queueing the work
behind our back, the code transitioned the device to PSMOUSE_CMD_MODE
while holding the mutex, then dropped the mutex and cancelled the work.

When cancel_work_sync() was replaced with disable_work_sync() in this
path, the mutex juggling remained. However, disable_work_sync()
inherently prevents the work from being executed or re-queued, making
the mutex juggling unnecessary.

Clean this up by moving disable_work_sync() to the very top of
psmouse_disconnect(), before we acquire psmouse_mutex.

Assisted-by: Antigravity:gemini-3.5-flash
Signed-off-by: Dmitry Torokhov <[email protected]>
---
 drivers/input/mouse/psmouse-base.c | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/drivers/input/mouse/psmouse-base.c b/drivers/input/mouse/psmouse-base.c
index 916a14b9b6a7..3fcc1d293c31 100644
--- a/drivers/input/mouse/psmouse-base.c
+++ b/drivers/input/mouse/psmouse-base.c
@@ -1458,15 +1458,12 @@ static void psmouse_disconnect(struct serio *serio)
 	struct psmouse *psmouse = psmouse_from_serio(serio);
 	struct psmouse *parent = NULL;
 
+	disable_work_sync(&psmouse->resync_work);
+
 	mutex_lock(&psmouse_mutex);
 
 	psmouse_set_state(psmouse, PSMOUSE_CMD_MODE);
 
-	/* make sure we don't have a resync in progress */
-	mutex_unlock(&psmouse_mutex);
-	disable_work_sync(&psmouse->resync_work);
-	mutex_lock(&psmouse_mutex);
-
 	if (serio->parent && serio->id.type == SERIO_PS_PSTHRU) {
 		parent = psmouse_from_serio(serio->parent);
 		psmouse_deactivate(parent);
-- 
2.55.0.229.g6434b31f56-goog