| Message ID | 20180302145509.24563-1-maxime.chevallier@bootlin.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | ce99319a182fe766be67f96338386f3ec73e321c |
| Headers | show |
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@bootlin.com> > --- > 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> -- To unsubscribe from this list: send the line "unsubscribe linux-spi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index b33a727a0158..4153f959f28c 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -779,8 +779,14 @@ static int spi_map_buf(struct spi_controller *ctlr, struct device *dev, for (i = 0; i < sgs; i++) { if (vmalloced_buf || kmap_buf) { - min = min_t(size_t, - len, desc_len - offset_in_page(buf)); + /* + * Next scatterlist entry size is the minimum between + * the desc_len and the remaining buffer length that + * fits in a page. + */ + min = min_t(size_t, desc_len, + min_t(size_t, len, + PAGE_SIZE - offset_in_page(buf))); if (vmalloced_buf) vm_page = vmalloc_to_page(buf); else
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@bootlin.com> --- drivers/spi/spi.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-)