From: Vinod Koul <vkoul@kernel.org>
To: Johan Hovold <johan@kernel.org>
Cc: "yukuai (C)" <yukuai3@huawei.com>,
mcoquelin.stm32@gmail.com, alexandre.torgue@foss.st.com,
michal.simek@xilinx.com, dmaengine@vger.kernel.org,
linux-kernel@vger.kernel.org,
linux-stm32@st-md-mailman.stormreply.com,
linux-arm-kernel@lists.infradead.org, yi.zhang@huawei.com
Subject: Re: [PATCH 2/3] dmaengine: usb-dmac: Fix PM reference leak in usb_dmac_probe()
Date: Mon, 7 Jun 2021 15:49:09 +0530 [thread overview]
Message-ID: <YL3ynd1KiJoe9y6+@vkoul-mobl> (raw)
In-Reply-To: <YL3TlDqe4KSr3ICl@hovoldconsulting.com>
On 07-06-21, 10:06, Johan Hovold wrote:
> On Thu, Jun 03, 2021 at 04:39:08PM +0530, Vinod Koul wrote:
> > On 31-05-21, 11:19, Johan Hovold wrote:
> > > On Mon, May 31, 2021 at 02:27:34PM +0530, Vinod Koul wrote:
> > > > On 31-05-21, 14:11, yukuai (C) wrote:
> > > > > On 2021/05/31 12:00, Vinod Koul wrote:
> > > > > > On 17-05-21, 16:18, Yu Kuai wrote:
> > > > > > > pm_runtime_get_sync will increment pm usage counter even it failed.
> > > > > > > Forgetting to putting operation will result in reference leak here.
> > > > > > > Fix it by replacing it with pm_runtime_resume_and_get to keep usage
> > > > > > > counter balanced.
>
> > > > Yes the rumtime_pm is disabled on failure here and the count would have
> > > > no consequence...
> > >
> > > You should still balance the PM usage counter as it isn't reset for
> > > example when reloading the driver.
> >
> > Should I driver trust that on load PM usage counter is balanced and not
> > to be reset..?
>
> Not sure what you're asking here. But a driver should never leave the PM
> usage counter unbalanced.
Thinking about again, yes we should safely assume the counter is
balanced when driver loads.. so unloading while balancing sounds better
behaviour
Thanks
--
~Vinod
next prev parent reply other threads:[~2021-06-07 10:19 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-17 8:18 [PATCH 0/3] cleanup patches for PM reference leak Yu Kuai
2021-05-17 8:18 ` [PATCH 1/3] dmaengine: stm32-mdma: fix PM reference leak in stm32_mdma_alloc_chan_resourc() Yu Kuai
2021-05-31 4:03 ` Vinod Koul
2021-05-17 8:18 ` [PATCH 2/3] dmaengine: usb-dmac: Fix PM reference leak in usb_dmac_probe() Yu Kuai
2021-05-31 4:00 ` Vinod Koul
2021-05-31 6:11 ` yukuai (C)
2021-05-31 8:57 ` Vinod Koul
2021-05-31 9:19 ` Johan Hovold
2021-06-03 11:09 ` Vinod Koul
2021-06-07 8:06 ` Johan Hovold
2021-06-07 10:19 ` Vinod Koul [this message]
2021-07-05 8:41 ` yukuai (C)
2021-07-06 10:49 ` Vinod Koul
2021-05-17 8:18 ` [PATCH 3/3] dmaengine: zynqmp_dma: Fix PM reference leak in zynqmp_dma_alloc_chan_resourc() Yu Kuai
2021-05-31 4:03 ` Vinod Koul
2021-05-29 9:13 ` [PATCH 0/3] cleanup patches for PM reference leak yukuai (C)
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