Re: [PATCH] spi: Ensure memory used for spi_write_then_read() is DMA safe

From: Grant Likely
Date: Tue Feb 05 2013 - 09:21:37 EST


On Sun, 27 Jan 2013 14:35:04 +0800, Mark Brown <broonie@xxxxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
> Use GFP_DMA in order to ensure that the memory we allocate for transfers
> in spi_write_then_read() can be DMAed. On most platforms this will have
> no effect.
>
> Signed-off-by: Mark Brown <broonie@xxxxxxxxxxxxxxxxxxxxxxxxxxx>

Applied, thanks.

g.

> ---
> drivers/spi/spi.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
> index 19ee901..14d0fba 100644
> --- a/drivers/spi/spi.c
> +++ b/drivers/spi/spi.c
> @@ -1656,7 +1656,8 @@ int spi_write_then_read(struct spi_device *spi,
> * using the pre-allocated buffer or the transfer is too large.
> */
> if ((n_tx + n_rx) > SPI_BUFSIZ || !mutex_trylock(&lock)) {
> - local_buf = kmalloc(max((unsigned)SPI_BUFSIZ, n_tx + n_rx), GFP_KERNEL);
> + local_buf = kmalloc(max((unsigned)SPI_BUFSIZ, n_tx + n_rx),
> + GFP_KERNEL | GFP_DMA);
> if (!local_buf)
> return -ENOMEM;
> } else {
> --
> 1.7.10.4
>

--
Grant Likely, B.Sc, P.Eng.
Secret Lab Technologies, Ltd.
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