diff options
| author | Maxime Chevallier <maxime.chevallier@bootlin.com> | 2018-03-02 15:55:09 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-07-03 11:21:35 +0200 |
| commit | 9b46e5e9a300a4a01d422e9d21f694b54d6c2f5f (patch) | |
| tree | dd59d469e3e9e0307bd075d2ac8e6759c9c928ef | |
| parent | 0e1bd0206b0568e9756d5310e7f617c5c8b3e16d (diff) | |
spi: Fix scatterlist elements size in spi_map_buf
commit ce99319a182fe766be67f96338386f3ec73e321c upstream.
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
Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/spi/spi.c | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index dee1cb87d24f..04fd651f9e3e 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -707,8 +707,14 @@ static int spi_map_buf(struct spi_master *master, struct device *dev, for (i = 0; i < sgs; i++) { if (vmalloced_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))); vm_page = vmalloc_to_page(buf); if (!vm_page) { sg_free_table(sgt); |