[PATCH 04/28] ASoC: apple: mca: Fix PD link double-frees

[James Calligeros]

From: Hector Martin <marcan@xxxxxxxxx>

Add additional checks to ensure MCA PD links are not double freed.

Fixes: 3df5d0d97289 ("ASoC: apple: mca: Start new platform driver")
Signed-off-by: Hector Martin <marcan@xxxxxxxxx>
Signed-off-by: James Calligeros <jcalligeros99@xxxxxxxxx>
---
 sound/soc/apple/mca.c | 16 +++++++++++++---
 1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/sound/soc/apple/mca.c b/sound/soc/apple/mca.c
index be702b2942a5..66196c6a9273 100644
--- a/sound/soc/apple/mca.c
+++ b/sound/soc/apple/mca.c
@@ -303,6 +303,7 @@ static int mca_fe_enable_clocks(struct mca_cluster *cl)
 	 * the power state driver would error out on seeing the device
 	 * as clock-gated.
 	 */
+	WARN_ON(cl->pd_link);
 	cl->pd_link = device_link_add(mca->dev, cl->pd_dev,
 				      DL_FLAG_STATELESS | DL_FLAG_PM_RUNTIME |
 					      DL_FLAG_RPM_ACTIVE);
@@ -326,7 +327,11 @@ static void mca_fe_disable_clocks(struct mca_cluster *cl)
 	mca_modify(cl, REG_SYNCGEN_STATUS, SYNCGEN_STATUS_EN, 0);
 	mca_modify(cl, REG_STATUS, STATUS_MCLK_EN, 0);
 
-	device_link_del(cl->pd_link);
+	if (cl->pd_link) {
+		device_link_del(cl->pd_link);
+		cl->pd_link = NULL;
+	}
+
 	clk_disable_unprepare(cl->clk_parent);
 }
 
@@ -392,6 +397,7 @@ static int mca_fe_prepare(struct snd_pcm_substream *substream,
 	if (!cl->syncgen_in_use) {
 		int port = ffs(mca_fe_get_portmask(substream));
 
+		WARN_ON(cl->pd_link);
 		cl->pd_link = device_link_add(mca->dev, cl->pd_dev,
 					      DL_FLAG_STATELESS | DL_FLAG_PM_RUNTIME |
 						DL_FLAG_RPM_ACTIVE);
@@ -423,8 +429,10 @@ static int mca_fe_hw_free(struct snd_pcm_substream *substream,
 		return 0;
 
 	mca_modify(cl, REG_SYNCGEN_STATUS, SYNCGEN_STATUS_EN, 0);
-	if (cl->pd_link)
+	if (cl->pd_link) {
 		device_link_del(cl->pd_link);
+		cl->pd_link = NULL;
+	}
 
 	return 0;
 }
@@ -1145,8 +1153,10 @@ static void apple_mca_release(struct mca_data *mca)
 			dev_pm_domain_detach(cl->pd_dev, true);
 	}
 
-	if (mca->pd_link)
+	if (mca->pd_link) {
 		device_link_del(mca->pd_link);
+		mca->pd_link = NULL;
+	}
 
 	if (!IS_ERR_OR_NULL(mca->pd_dev))
 		dev_pm_domain_detach(mca->pd_dev, true);

-- 
2.55.0