linux-kernel - [PATCH v2 1/7] media: mediatek: vcodec: fix possible unbalanced PM counter

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Message-Id: <20231215104551.233679-1-eugen.hristev@collabora.com>
Date: Fri, 15 Dec 2023 12:45:45 +0200
From: Eugen Hristev <eugen.hristev@...labora.com>
To: linux-mediatek@...ts.infradead.org
Cc: linux-arm-kernel@...ts.infradead.org,
	linux-kernel@...r.kernel.org,
	devicetree@...r.kernel.org,
	angelogioacchino.delregno@...labora.com,
	matthias.bgg@...il.com,
	linux-media@...r.kernel.org,
	tiffany.lin@...iatek.com,
	andrew-ct.chen@...iatek.com,
	Eugen Hristev <eugen.hristev@...labora.com>
Subject: [PATCH v2 1/7] media: mediatek: vcodec: fix possible unbalanced PM counter

It is possible that mtk_vcodec_enc_pw_on fails, and in that scenario
the PM counter is not incremented, and subsequent call to
mtk_vcodec_enc_pw_off decrements the counter, leading to a PM imbalance.
Fix by bailing out of venc_if_encode in the case when mtk_vcodec_enc_pw_on
fails.

Fixes: 4e855a6efa54 ("[media] vcodec: mediatek: Add Mediatek V4L2 Video Encoder Driver")
Signed-off-by: Eugen Hristev <eugen.hristev@...labora.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>
---
Changes in v2:
- collect R-b

 .../platform/mediatek/vcodec/encoder/mtk_vcodec_enc_pm.c     | 4 +++-
 .../platform/mediatek/vcodec/encoder/mtk_vcodec_enc_pm.h     | 2 +-
 drivers/media/platform/mediatek/vcodec/encoder/venc_drv_if.c | 5 ++++-
 3 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/drivers/media/platform/mediatek/vcodec/encoder/mtk_vcodec_enc_pm.c b/drivers/media/platform/mediatek/vcodec/encoder/mtk_vcodec_enc_pm.c
index a22b7dfc656e..1a2b14a3e219 100644
--- a/drivers/media/platform/mediatek/vcodec/encoder/mtk_vcodec_enc_pm.c
+++ b/drivers/media/platform/mediatek/vcodec/encoder/mtk_vcodec_enc_pm.c
@@ -58,13 +58,15 @@ int mtk_vcodec_init_enc_clk(struct mtk_vcodec_enc_dev *mtkdev)
 	return 0;
 }
 
-void mtk_vcodec_enc_pw_on(struct mtk_vcodec_pm *pm)
+int mtk_vcodec_enc_pw_on(struct mtk_vcodec_pm *pm)
 {
 	int ret;
 
 	ret = pm_runtime_resume_and_get(pm->dev);
 	if (ret)
 		dev_err(pm->dev, "pm_runtime_resume_and_get fail: %d", ret);
+
+	return ret;
 }
 
 void mtk_vcodec_enc_pw_off(struct mtk_vcodec_pm *pm)
diff --git a/drivers/media/platform/mediatek/vcodec/encoder/mtk_vcodec_enc_pm.h b/drivers/media/platform/mediatek/vcodec/encoder/mtk_vcodec_enc_pm.h
index 157ea08ba9e3..2e28f25e36cc 100644
--- a/drivers/media/platform/mediatek/vcodec/encoder/mtk_vcodec_enc_pm.h
+++ b/drivers/media/platform/mediatek/vcodec/encoder/mtk_vcodec_enc_pm.h
@@ -10,7 +10,7 @@
 #include "mtk_vcodec_enc_drv.h"
 
 int mtk_vcodec_init_enc_clk(struct mtk_vcodec_enc_dev *dev);
-void mtk_vcodec_enc_pw_on(struct mtk_vcodec_pm *pm);
+int mtk_vcodec_enc_pw_on(struct mtk_vcodec_pm *pm);
 void mtk_vcodec_enc_pw_off(struct mtk_vcodec_pm *pm);
 void mtk_vcodec_enc_clock_on(struct mtk_vcodec_pm *pm);
 void mtk_vcodec_enc_clock_off(struct mtk_vcodec_pm *pm);
diff --git a/drivers/media/platform/mediatek/vcodec/encoder/venc_drv_if.c b/drivers/media/platform/mediatek/vcodec/encoder/venc_drv_if.c
index c402a686f3cb..e83747b8d69a 100644
--- a/drivers/media/platform/mediatek/vcodec/encoder/venc_drv_if.c
+++ b/drivers/media/platform/mediatek/vcodec/encoder/venc_drv_if.c
@@ -64,7 +64,9 @@ int venc_if_encode(struct mtk_vcodec_enc_ctx *ctx,
 	ctx->dev->curr_ctx = ctx;
 	spin_unlock_irqrestore(&ctx->dev->irqlock, flags);
 
-	mtk_vcodec_enc_pw_on(&ctx->dev->pm);
+	ret = mtk_vcodec_enc_pw_on(&ctx->dev->pm);
+	if (ret)
+		goto venc_if_encode_pw_on_err;
 	mtk_vcodec_enc_clock_on(&ctx->dev->pm);
 	ret = ctx->enc_if->encode(ctx->drv_handle, opt, frm_buf,
 				  bs_buf, result);
@@ -75,6 +77,7 @@ int venc_if_encode(struct mtk_vcodec_enc_ctx *ctx,
 	ctx->dev->curr_ctx = NULL;
 	spin_unlock_irqrestore(&ctx->dev->irqlock, flags);
 
+venc_if_encode_pw_on_err:
 	mtk_venc_unlock(ctx);
 	return ret;
 }
-- 
2.34.1