linux-kernel - [PATCH] i3c: master: svc: fix cpu schedule in spin lock

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Date:   Wed, 17 May 2023 11:30:29 +0800
From:   Clark Wang <xiaoning.wang@....com>
To:     miquel.raynal@...tlin.com, conor.culhane@...vaco.com,
        alexandre.belloni@...tlin.com
Cc:     linux-i3c@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: [PATCH] i3c: master: svc: fix cpu schedule in spin lock

pm_runtime_resume_and_get() may call sleep(). It cannot be used in
svc_i3c_master_start_xfer_locked(), because it is in a spin lock.

Move the pm runtime operations to svc_i3c_master_enqueue_xfer().

Signed-off-by: Clark Wang <xiaoning.wang@....com>
Fixes: 05be23ef78f7 ("i3c: master: svc: add runtime pm support")
---
 drivers/i3c/master/svc-i3c-master.c | 19 ++++++++++---------
 1 file changed, 10 insertions(+), 9 deletions(-)

diff --git a/drivers/i3c/master/svc-i3c-master.c b/drivers/i3c/master/svc-i3c-master.c
index bca3a4352ad1..4edf33ed207d 100644
--- a/drivers/i3c/master/svc-i3c-master.c
+++ b/drivers/i3c/master/svc-i3c-master.c
@@ -1096,12 +1096,6 @@ static void svc_i3c_master_start_xfer_locked(struct svc_i3c_master *master)
 	if (!xfer)
 		return;
 
-	ret = pm_runtime_resume_and_get(master->dev);
-	if (ret < 0) {
-		dev_err(master->dev, "<%s> Cannot get runtime PM.\n", __func__);
-		return;
-	}
-
 	svc_i3c_master_clear_merrwarn(master);
 	svc_i3c_master_flush_fifo(master);
 
@@ -1116,9 +1110,6 @@ static void svc_i3c_master_start_xfer_locked(struct svc_i3c_master *master)
 			break;
 	}
 
-	pm_runtime_mark_last_busy(master->dev);
-	pm_runtime_put_autosuspend(master->dev);
-
 	xfer->ret = ret;
 	complete(&xfer->comp);
 
@@ -1139,6 +1130,13 @@ static void svc_i3c_master_enqueue_xfer(struct svc_i3c_master *master,
 					struct svc_i3c_xfer *xfer)
 {
 	unsigned long flags;
+	int ret;
+
+	ret = pm_runtime_resume_and_get(master->dev);
+	if (ret < 0) {
+		dev_err(master->dev, "<%s> Cannot get runtime PM.\n", __func__);
+		return;
+	}
 
 	init_completion(&xfer->comp);
 	spin_lock_irqsave(&master->xferqueue.lock, flags);
@@ -1149,6 +1147,9 @@ static void svc_i3c_master_enqueue_xfer(struct svc_i3c_master *master,
 		svc_i3c_master_start_xfer_locked(master);
 	}
 	spin_unlock_irqrestore(&master->xferqueue.lock, flags);
+
+	pm_runtime_mark_last_busy(master->dev);
+	pm_runtime_put_autosuspend(master->dev);
 }
 
 static bool
-- 
2.34.1