linux-kernel - [PATCH 5.4 18/84] usb: typec: ucsi: Fix role swapping

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Date:   Wed,  4 May 2022 18:43:59 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org,
        Heikki Krogerus <heikki.krogerus@...ux.intel.com>,
        Jia-Ju Bai <baijiaju1990@...il.com>
Subject: [PATCH 5.4 18/84] usb: typec: ucsi: Fix role swapping

From: Heikki Krogerus <heikki.krogerus@...ux.intel.com>

commit eb5d7ff3cf0d55093c619b5ad107cd5c05ce8134 upstream.

All attempts to swap the roles timed out because the
completion was done without releasing the port lock. Fixing
that by releasing the lock before starting to wait for the
completion.

Link: https://lore.kernel.org/linux-usb/037de7ac-e210-bdf5-ec7a-8c0c88a0be20@gmail.com/
Fixes: ad74b8649bea ("usb: typec: ucsi: Preliminary support for alternate modes")
Cc: stable@...r.kernel.org
Reported-and-tested-by: Jia-Ju Bai <baijiaju1990@...il.com>
Signed-off-by: Heikki Krogerus <heikki.krogerus@...ux.intel.com>
Link: https://lore.kernel.org/r/20220405134824.68067-3-heikki.krogerus@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 drivers/usb/typec/ucsi/ucsi.c |   20 +++++++++++++-------
 1 file changed, 13 insertions(+), 7 deletions(-)

--- a/drivers/usb/typec/ucsi/ucsi.c
+++ b/drivers/usb/typec/ucsi/ucsi.c
@@ -748,14 +748,18 @@ ucsi_dr_swap(const struct typec_capabili
 	if (ret < 0)
 		goto out_unlock;
 
+	mutex_unlock(&con->lock);
+
 	if (!wait_for_completion_timeout(&con->complete,
-					msecs_to_jiffies(UCSI_SWAP_TIMEOUT_MS)))
-		ret = -ETIMEDOUT;
+					 msecs_to_jiffies(UCSI_SWAP_TIMEOUT_MS)))
+		return -ETIMEDOUT;
+
+	return 0;
 
 out_unlock:
 	mutex_unlock(&con->lock);
 
-	return ret < 0 ? ret : 0;
+	return ret;
 }
 
 static int
@@ -780,11 +784,13 @@ ucsi_pr_swap(const struct typec_capabili
 	if (ret < 0)
 		goto out_unlock;
 
+	mutex_unlock(&con->lock);
+
 	if (!wait_for_completion_timeout(&con->complete,
-				msecs_to_jiffies(UCSI_SWAP_TIMEOUT_MS))) {
-		ret = -ETIMEDOUT;
-		goto out_unlock;
-	}
+					 msecs_to_jiffies(UCSI_SWAP_TIMEOUT_MS)))
+		return -ETIMEDOUT;
+
+	mutex_lock(&con->lock);
 
 	/* Something has gone wrong while swapping the role */
 	if (con->status.pwr_op_mode != UCSI_CONSTAT_PWR_OPMODE_PD) {