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Date: Fri, 21 May 2010 12:01:06 -0700
From: Andrew Morton <akpm@linux-foundation.org>
To: Anders Larsen <al@alarsen.net>
Subject: Re: [PATCH] Fix Oops with Atmel SPI
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Cc: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>,
	Ian McDonnell <ian@brightstareng.com>,
	Haavard Skinnemoen <hskinnemoen@atmel.com>,
	Nicolas Pitre <nico@fluxnic.net>, linux-kernel@vger.kernel.org,
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	Matthias Kaehlcke <matthias@kaehlcke.net>,
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On Wed, 19 May 2010 13:05:00 +0200
Anders Larsen <al@alarsen.net> wrote:

> On 2010-04-22 00:24:10, Andrew Morton wrote:
> > Finally..  Wouldn't it be better to just fix the atmel SPI driver so
> > that it doesn't barf when handed vmalloc'ed memory?  Who do we ridicule
> > about that?  <checks, adds cc>
> 
> You mean something like this instead?

That looks simple enough.  How do we get it tested, changelogged and
merged up?  Haavard, can you please take a look?


> diff --git a/drivers/spi/atmel_spi.c b/drivers/spi/atmel_spi.c
> index c4e0442..a9ad5e8 100644
> --- a/drivers/spi/atmel_spi.c
> +++ b/drivers/spi/atmel_spi.c
> @@ -352,16 +352,30 @@ atmel_spi_dma_map_xfer(struct atmel_spi *as, struct spi_transfer *xfer)
>  
>  	xfer->tx_dma = xfer->rx_dma = INVALID_DMA_ADDRESS;
>  	if (xfer->tx_buf) {
> -		xfer->tx_dma = dma_map_single(dev,
> -				(void *) xfer->tx_buf, xfer->len,
> -				DMA_TO_DEVICE);
> +		if (is_vmalloc_addr(xfer->tx_buf))
> +			xfer->tx_dma = dma_map_page(dev,
> +					vmalloc_to_page(xfer->tx_buf),
> +					(unsigned long)xfer->tx_buf & (PAGE_SIZE-1),
> +					xfer->len,
> +					DMA_TO_DEVICE);
> +		else
> +			xfer->tx_dma = dma_map_single(dev,
> +					(void *) xfer->tx_buf, xfer->len,
> +					DMA_TO_DEVICE);
>  		if (dma_mapping_error(dev, xfer->tx_dma))
>  			return -ENOMEM;
>  	}
>  	if (xfer->rx_buf) {
> -		xfer->rx_dma = dma_map_single(dev,
> -				xfer->rx_buf, xfer->len,
> -				DMA_FROM_DEVICE);
> +		if (is_vmalloc_addr(xfer->rx_buf))
> +			xfer->rx_dma = dma_map_page(dev,
> +					vmalloc_to_page(xfer->rx_buf),
> +					(unsigned long)xfer->rx_buf & (PAGE_SIZE-1),
> +					xfer->len,
> +					DMA_FROM_DEVICE);
> +		else
> +			xfer->rx_dma = dma_map_single(dev,
> +					xfer->rx_buf, xfer->len,
> +					DMA_FROM_DEVICE);
>  		if (dma_mapping_error(dev, xfer->rx_dma)) {
>  			if (xfer->tx_buf)
>  				dma_unmap_single(dev,
>