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Commit 31705e21 authored by Guennadi Liakhovetski's avatar Guennadi Liakhovetski Committed by Paul Mundt
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dmaengine: shdma: synchronize RCU before freeing, simplify spinlock 



List elements, deleted using list_del_rcu(), cannot be freed without
synchronising RCU. Further, the spinlock, used to protect the RCU
writer, is called in process context, so, we don't have to save flags.

Signed-off-by: default avatarGuennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: default avatarPaul Mundt <lethal@linux-sh.org>
parent 467017b8

drivers/dma/shdma.c

+8 −8
Original line number Diff line number Diff line
@@ -1077,7 +1077,6 @@ static int __init sh_dmae_probe(struct platform_device *pdev) 
	struct sh_dmae_pdata *pdata = pdev->dev.platform_data;

	unsigned long irqflags = IRQF_DISABLED,

		chan_flag[SH_DMAC_MAX_CHANNELS] = {};

	unsigned long flags;

	int errirq, chan_irq[SH_DMAC_MAX_CHANNELS];

	int err, i, irq_cnt = 0, irqres = 0;

	struct sh_dmae_device *shdev;
@@ -1143,9 +1142,9 @@ static int __init sh_dmae_probe(struct platform_device *pdev) 
	pm_runtime_enable(&pdev->dev);

	pm_runtime_get_sync(&pdev->dev);



	spin_lock_irqsave(&sh_dmae_lock, flags);

	spin_lock_irq(&sh_dmae_lock);

	list_add_tail_rcu(&shdev->node, &sh_dmae_devices);

	spin_unlock_irqrestore(&sh_dmae_lock, flags);

	spin_unlock_irq(&sh_dmae_lock);



	/* reset dma controller - only needed as a test */

	err = sh_dmae_rst(shdev);
@@ -1250,9 +1249,9 @@ static int __init sh_dmae_probe(struct platform_device *pdev) 
eirq_err:

#endif

rst_err:

	spin_lock_irqsave(&sh_dmae_lock, flags);

	spin_lock_irq(&sh_dmae_lock);

	list_del_rcu(&shdev->node);

	spin_unlock_irqrestore(&sh_dmae_lock, flags);

	spin_unlock_irq(&sh_dmae_lock);



	pm_runtime_put(&pdev->dev);

	pm_runtime_disable(&pdev->dev);
@@ -1261,6 +1260,7 @@ static int __init sh_dmae_probe(struct platform_device *pdev) 
		iounmap(shdev->dmars);

emapdmars:

	iounmap(shdev->chan_reg);

	synchronize_rcu();

emapchan:

	kfree(shdev);

ealloc:
@@ -1276,7 +1276,6 @@ static int __exit sh_dmae_remove(struct platform_device *pdev) 
{

	struct sh_dmae_device *shdev = platform_get_drvdata(pdev);

	struct resource *res;

	unsigned long flags;

	int errirq = platform_get_irq(pdev, 0);



	dma_async_device_unregister(&shdev->common);
@@ -1284,9 +1283,9 @@ static int __exit sh_dmae_remove(struct platform_device *pdev) 
	if (errirq > 0)

		free_irq(errirq, shdev);



	spin_lock_irqsave(&sh_dmae_lock, flags);

	spin_lock_irq(&sh_dmae_lock);

	list_del_rcu(&shdev->node);

	spin_unlock_irqrestore(&sh_dmae_lock, flags);

	spin_unlock_irq(&sh_dmae_lock);



	/* channel data remove */

	sh_dmae_chan_remove(shdev);
@@ -1297,6 +1296,7 @@ static int __exit sh_dmae_remove(struct platform_device *pdev) 
		iounmap(shdev->dmars);

	iounmap(shdev->chan_reg);



	synchronize_rcu();

	kfree(shdev);



	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);