diff options
| author | Maxime Chevallier <maxime.chevallier@bootlin.com> | 2018-03-02 15:55:09 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-04-24 09:34:10 +0200 |
| commit | 34023ca384a75c064544b92bad7bd347afdb3067 (patch) | |
| tree | c75ba1f0d4bc80709379189bd31bf37d5295e50a /drivers/spi | |
| parent | 61ec8502373923c3bcad5e3b35155922bfc07d75 (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: Greg Kroah-Hartman <gregkh@linuxfoundation.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 6db80635ace8..c2e85e23d538 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -743,8 +743,14 @@ static int spi_map_buf(struct spi_master *master, 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 |