Commit c1aefbdd authored Nov 17, 2014 by Charles Keepax Committed by Mark Brown Nov 17, 2014

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

parent f114040e

drivers/spi/spi.c

+3 −3

Original line number	Diff line number	Diff line
		@@ -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;

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