linux-kernel - Re: [PATCH v4 04/14] dmaengine: tegra-apb: Clean up tasklet releasing

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Date:   Tue, 14 Jan 2020 15:36:00 +0000
From:   Jon Hunter <jonathanh@...dia.com>
To:     Dmitry Osipenko <digetx@...il.com>,
        Laxman Dewangan <ldewangan@...dia.com>,
        Vinod Koul <vkoul@...nel.org>,
        Dan Williams <dan.j.williams@...el.com>,
        Thierry Reding <thierry.reding@...il.com>,
        Michał Mirosław <mirq-linux@...e.qmqm.pl>
CC:     <dmaengine@...r.kernel.org>, <linux-tegra@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v4 04/14] dmaengine: tegra-apb: Clean up tasklet releasing


On 12/01/2020 17:29, Dmitry Osipenko wrote:
> There is no need to kill tasklet when driver's probe fails because tasklet
> can't be scheduled at this time. It is also cleaner to kill tasklet on
> channel's freeing rather than to kill it on driver's removal, otherwise
> tasklet could perform a dummy execution after channel's releasing, which
> isn't very nice.
> 
> Signed-off-by: Dmitry Osipenko <digetx@...il.com>
> ---
>  drivers/dma/tegra20-apb-dma.c | 6 +-----
>  1 file changed, 1 insertion(+), 5 deletions(-)
> 
> diff --git a/drivers/dma/tegra20-apb-dma.c b/drivers/dma/tegra20-apb-dma.c
> index 24ad3a5a04e3..1b8a11804962 100644
> --- a/drivers/dma/tegra20-apb-dma.c
> +++ b/drivers/dma/tegra20-apb-dma.c
> @@ -1287,7 +1287,6 @@ static void tegra_dma_free_chan_resources(struct dma_chan *dc)
>  	struct tegra_dma_sg_req *sg_req;
>  	struct list_head dma_desc_list;
>  	struct list_head sg_req_list;
> -	unsigned long flags;
>  
>  	INIT_LIST_HEAD(&dma_desc_list);
>  	INIT_LIST_HEAD(&sg_req_list);
> @@ -1295,15 +1294,14 @@ static void tegra_dma_free_chan_resources(struct dma_chan *dc)
>  	dev_dbg(tdc2dev(tdc), "Freeing channel %d\n", tdc->id);
>  
>  	tegra_dma_terminate_all(dc);
> +	tasklet_kill(&tdc->tasklet);
>  
> -	spin_lock_irqsave(&tdc->lock, flags);
>  	list_splice_init(&tdc->pending_sg_req, &sg_req_list);
>  	list_splice_init(&tdc->free_sg_req, &sg_req_list);
>  	list_splice_init(&tdc->free_dma_desc, &dma_desc_list);
>  	INIT_LIST_HEAD(&tdc->cb_desc);
>  	tdc->config_init = false;
>  	tdc->isr_handler = NULL;
> -	spin_unlock_irqrestore(&tdc->lock, flags);
>  
>  	while (!list_empty(&dma_desc_list)) {
>  		dma_desc = list_first_entry(&dma_desc_list,
> @@ -1542,7 +1540,6 @@ static int tegra_dma_probe(struct platform_device *pdev)
>  		struct tegra_dma_channel *tdc = &tdma->channels[i];
>  
>  		free_irq(tdc->irq, tdc);
> -		tasklet_kill(&tdc->tasklet);
>  	}
>  
>  	pm_runtime_disable(&pdev->dev);
> @@ -1562,7 +1559,6 @@ static int tegra_dma_remove(struct platform_device *pdev)
>  	for (i = 0; i < tdma->chip_data->nr_channels; ++i) {
>  		tdc = &tdma->channels[i];
>  		free_irq(tdc->irq, tdc);
> -		tasklet_kill(&tdc->tasklet);
>  	}
>  
>  	pm_runtime_disable(&pdev->dev);

Acked-by: Jon Hunter <jonathanh@...dia.com>

Cheers
Jon

-- 
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