Re: [PATCH 5.10 14/86] dmaengine: mediatek:Fix PM usage reference leak of mtk_uart_apdma_alloc_chan_resources

Pavel Machek
2022-04-27T20:33:19Z

[-- Attachment #1: Type: text/plain, Size: 1238 bytes --]

Hi!

> > pm_runtime_get_sync will increment pm usage counter even it failed.
> > Forgetting to putting operation will result in reference leak here.
> > We fix it:
> > 1) Replacing it with pm_runtime_resume_and_get to keep usage counter
> > balanced.
>
> Suspect.
>
> > 2) Add putting operation before returning error.
>
> Yes but you also put in success case, which is likely
> wrong. mtk_uart_apdma_free_chan_resources() does second put.

This is possible fix for the second problem:

Signed-off-by: Pavel Machek <pavel@denx.de>

diff --git a/drivers/dma/mediatek/mtk-uart-apdma.c b/drivers/dma/mediatek/mtk-uart-apdma.c
index a1517ef1f4a0..8ec046a7e714 100644
--- a/drivers/dma/mediatek/mtk-uart-apdma.c
+++ b/drivers/dma/mediatek/mtk-uart-apdma.c
@@ -300,7 +300,8 @@ static int mtk_uart_apdma_alloc_chan_resources(struct dma_chan *chan)

if (mtkd->support_33bits)
mtk_uart_apdma_write(c, VFF_4G_SUPPORT, VFF_4G_SUPPORT_CLR_B);
-
+ return 0;
+
err_pm:
pm_runtime_put_noidle(mtkd->ddev.dev);
return ret;

Best regards,
Pavel

--
DENX Software Engineering GmbH, Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 195 bytes --]