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| author |   Maxime Chevallier <maxime.chevallier@bootlin.com> | 2018-03-02 15:55:09 +0100 |
|---|---|---|
| committer |   Mark Brown <broonie@kernel.org> | 2018-03-02 17:31:39 +0000 |
| commit | ce99319a182fe766be67f96338386f3ec73e321c (patch) | |
| tree | 91838b4a8050a41e4aada0fd88bee30cde61b379 /drivers/spi | |
| parent | Linux 4.16-rc1 (diff) | |
| download | linux-dev-ce99319a182fe766be67f96338386f3ec73e321c.tar.xz linux-dev-ce99319a182fe766be67f96338386f3ec73e321c.zip | |
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')
| -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 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 |