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authorMaxime Chevallier <maxime.chevallier@bootlin.com>2018-03-02 15:55:09 +0100
committerMark Brown <broonie@kernel.org>2018-03-02 17:31:39 +0000
commitce99319a182fe766be67f96338386f3ec73e321c (patch)
tree91838b4a8050a41e4aada0fd88bee30cde61b379 /drivers/spi/spi.c
parent7928b2cbe55b2a410a0f5c1f154610059c57b1b2 (diff)
spi: Fix scatterlist elements size in spi_map_buf
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> Signed-off-by: Mark Brown <broonie@kernel.org> Cc: stable@vger.kernel.org
Diffstat (limited to 'drivers/spi/spi.c')
-rw-r--r--drivers/spi/spi.c10
1 files changed, 8 insertions, 2 deletions
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