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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: 65598c13fd
("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
This commit is contained in:
parent
7928b2cbe5
commit
ce99319a18
1 changed files with 8 additions and 2 deletions
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@ -779,8 +779,14 @@ static int spi_map_buf(struct spi_controller *ctlr, struct device *dev,
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for (i = 0; i < sgs; i++) {
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if (vmalloced_buf || kmap_buf) {
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min = min_t(size_t,
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len, desc_len - offset_in_page(buf));
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/*
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* Next scatterlist entry size is the minimum between
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* the desc_len and the remaining buffer length that
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* fits in a page.
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*/
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min = min_t(size_t, desc_len,
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min_t(size_t, len,
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PAGE_SIZE - offset_in_page(buf)));
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if (vmalloced_buf)
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vm_page = vmalloc_to_page(buf);
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else
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