Re: [PATCH] spi: Fix scatterlist elements size in spi_map_buf

[Greg KH]

On Fri, Mar 02, 2018 at 03:55:09PM +0100, Maxime Chevallier wrote:
> When SPI transfers can be offloaded using DMA, the SPI core need to
> build a scatterlist to make sure that the buffer to be transferred is
> dma-able.
> 
> This patch fixes the scatterlist entry size computation in the case
> where the maximum acceptable scatterlist entry supported by the DMA
> controller is less than PAGE_SIZE, when the buffer is vmalloced.
> 
> For each entry, the actual size is given by the minimum between the
> desc_len (which is the max buffer size supported by the DMA controller)
> and the remaining buffer length until we cross a page boundary.
> 
> Fixes: 65598c13fd66 ("spi: Fix per-page mapping of unaligned vmalloc-ed buffer")
> Signed-off-by: Maxime Chevallier <maxime.chevallier@xxxxxxxxxxx>
> ---
>  drivers/spi/spi.c | 10 ++++++++--
>  1 file changed, 8 insertions(+), 2 deletions(-)

<formletter>

This is not the correct way to submit patches for inclusion in the
stable kernel tree.  Please read:
    https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html
for how to do this properly.

</formletter>