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Commit 3757e795 authored by H Hartley Sweeten's avatar H Hartley Sweeten Committed by Greg Kroah-Hartman
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staging: comedi: s626: tidy up freeing of the dma buffers 



Currently the dma buffers are freed during the detach of the driver using
the function s626_close_dma_b(). The buffers are also freed while the
interrupt handler is still attached. This could result in a race condition.

Refactor the code so that the buffers are freed after the interrupt handler
is released and the PCI device is disabled.

Signed-off-by: default avatarH Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: default avatarIan Abbott <abbotti@mev.co.uk>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent d558c596

drivers/staging/comedi/drivers/s626.c

+19 −25
Original line number Diff line number Diff line
@@ -2445,26 +2445,6 @@ static void s626_write_misc2(struct comedi_device *dev, uint16_t new_image) 
	s626_debi_write(dev, S626_LP_MISC1, S626_MISC1_WDISABLE);

}



static void s626_close_dma_b(struct comedi_device *dev,

			     struct s626_buffer_dma *pdma, size_t bsize)

{

	struct pci_dev *pcidev = comedi_to_pci_dev(dev);

	void *vbptr;

	dma_addr_t vpptr;



	if (pdma == NULL)

		return;



	/* find the matching allocation from the board struct */

	vbptr = pdma->logical_base;

	vpptr = pdma->physical_base;

	if (vbptr) {

		pci_free_consistent(pcidev, bsize, vbptr, vpptr);

		pdma->logical_base = NULL;

		pdma->physical_base = 0;

	}

}



static void s626_counters_init(struct comedi_device *dev)

{

	int chan;
@@ -2515,6 +2495,24 @@ static int s626_allocate_dma_buffers(struct comedi_device *dev) 
	return 0;

}



static void s626_free_dma_buffers(struct comedi_device *dev)

{

	struct pci_dev *pcidev = comedi_to_pci_dev(dev);

	struct s626_private *devpriv = dev->private;



	if (!devpriv)

		return;



	if (devpriv->rps_buf.logical_base)

		pci_free_consistent(pcidev, S626_DMABUF_SIZE,

				    devpriv->rps_buf.logical_base,

				    devpriv->rps_buf.physical_base);

	if (devpriv->ana_buf.logical_base)

		pci_free_consistent(pcidev, S626_DMABUF_SIZE,

				    devpriv->ana_buf.logical_base,

				    devpriv->ana_buf.physical_base);

}



static int s626_initialize(struct comedi_device *dev)

{

	struct s626_private *devpriv = dev->private;
@@ -2915,11 +2913,6 @@ static void s626_detach(struct comedi_device *dev) 
			/* Close all interfaces on 7146 device */

			writel(S626_MC1_SHUTDOWN, dev->mmio + S626_P_MC1);

			writel(S626_ACON1_BASE, dev->mmio + S626_P_ACON1);



			s626_close_dma_b(dev, &devpriv->rps_buf,

					 S626_DMABUF_SIZE);

			s626_close_dma_b(dev, &devpriv->ana_buf,

					 S626_DMABUF_SIZE);

		}



		if (dev->irq)
@@ -2928,6 +2921,7 @@ static void s626_detach(struct comedi_device *dev) 
			iounmap(dev->mmio);

	}

	comedi_pci_disable(dev);

	s626_free_dma_buffers(dev);

}



static struct comedi_driver s626_driver = {