From: "Michał Mirosław" <mirq-linux@rere.qmqm.pl>
To: Dmitry Osipenko <digetx@gmail.com>
Cc: Laxman Dewangan <ldewangan@nvidia.com>,
Vinod Koul <vkoul@kernel.org>,
Dan Williams <dan.j.williams@intel.com>,
Thierry Reding <thierry.reding@gmail.com>,
Jonathan Hunter <jonathanh@nvidia.com>,
dmaengine@vger.kernel.org, linux-tegra@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v1 3/7] dmaengine: tegra-apb: Prevent race conditions on channel's freeing
Date: Mon, 30 Dec 2019 21:50:54 +0100 [thread overview]
Message-ID: <20191230205054.GC24135@qmqm.qmqm.pl> (raw)
In-Reply-To: <20191230204555.GB24135@qmqm.qmqm.pl>
On Mon, Dec 30, 2019 at 09:45:55PM +0100, Michał Mirosław wrote:
> On Sat, Dec 28, 2019 at 11:46:36PM +0300, Dmitry Osipenko wrote:
> > It's unsafe to check the channel's "busy" state without taking a lock,
> > it is also unsafe to assume that tasklet isn't in-fly.
>
> 'in-flight'. Also, the patch seems to have two independent bug-fixes
> in it. Second one doesn't look right, at least not without an explanation.
>
> First:
>
> > - if (tdc->busy)
> > - tegra_dma_terminate_all(dc);
> > + tegra_dma_terminate_all(dc);
>
> Second:
>
> > + tasklet_kill(&tdc->tasklet);
BTW, maybe you can convert the code to threaded interrupt handler and
just get rid of the tasklet instead of fixing it?
Best Regards,
Michał Mirosław
next prev parent reply other threads:[~2019-12-30 20:51 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-28 20:46 [PATCH v1 0/7] NVIDIA Tegra APB DMA driver fixes and improvements Dmitry Osipenko
2019-12-28 20:46 ` [PATCH v1 1/7] dmaengine: tegra-apb: Fix use-after-free Dmitry Osipenko
2019-12-28 20:46 ` [PATCH v1 2/7] dmaengine: tegra-apb: Implement synchronization callback Dmitry Osipenko
2019-12-28 20:46 ` [PATCH v1 3/7] dmaengine: tegra-apb: Prevent race conditions on channel's freeing Dmitry Osipenko
2019-12-30 20:45 ` Michał Mirosław
2019-12-30 20:50 ` Michał Mirosław [this message]
2020-01-02 15:09 ` Dmitry Osipenko
2020-01-03 8:16 ` Michał Mirosław
2020-01-04 0:27 ` Dmitry Osipenko
2020-01-02 15:03 ` Dmitry Osipenko
2019-12-28 20:46 ` [PATCH v1 4/7] dmaengine: tegra-apb: Prevent race conditions of tasklet vs free list Dmitry Osipenko
2019-12-28 20:46 ` [PATCH v1 5/7] dmaengine: tegra-apb: Use devm_platform_ioremap_resource Dmitry Osipenko
2019-12-28 20:46 ` [PATCH v1 6/7] dmaengine: tegra-apb: Use devm_request_irq Dmitry Osipenko
2019-12-28 20:46 ` [PATCH v1 7/7] dmaengine: tegra-apb: Fix coding style problems Dmitry Osipenko
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