spi: Fix mapping from vmalloc-ed buffer to scatter list

We can only use page_address on memory that has been mapped using kmap,
when the buffer passed to the SPI has been allocated by vmalloc the page
has not necessarily been mapped through kmap. This means sometimes
page_address will return NULL causing the pointer we pass to sg_set_buf
to be invalid.

As we only call page_address so that we can pass a virtual address to
sg_set_buf which will then immediately call virt_to_page on it, fix this
by calling sg_set_page directly rather then relying on the sg_set_buf
helper.

Signed-off-by: Charles Keepax <ckeepax@opensource.wolfsonmicro.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Cc: stable@vger.kernel.org

diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index ebcb33df2eb22facb58cebc10277c3ab12925a42..50f20f243981e68b0d007ff714476d0a29a42a80 100644 (file)
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -615,13 +615,13 @@ static int spi_map_buf(struct spi_master *master, struct device *dev,
                                sg_free_table(sgt);
                                return -ENOMEM;
                        }
-                       sg_buf = page_address(vm_page) +
-                               ((size_t)buf & ~PAGE_MASK);
+                       sg_set_page(&sgt->sgl[i], vm_page,
+                                   min, offset_in_page(buf));
                } else {
                        sg_buf = buf;
+                       sg_set_buf(&sgt->sgl[i], sg_buf, min);
                }
 
-               sg_set_buf(&sgt->sgl[i], sg_buf, min);
 
                buf += min;
                len -= min;