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 --- drivers/spi/spi.c | 10 ++++++++-- 1 file 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
On Fri, Mar 02, 2018 at 03:55:09PM +0100, Maxime Chevallier wrote:
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
drivers/spi/spi.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-)
<formletter>
This is not the correct way to submit patches for inclusion in the stable kernel tree. Please read: https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html for how to do this properly.
</formletter>
The patch
spi: Fix scatterlist elements size in spi_map_buf
has been applied to the spi tree at
https://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi.git
All being well this means that it will be integrated into the linux-next tree (usually sometime in the next 24 hours) and sent to Linus during the next merge window (or sooner if it is a bug fix), however if problems are discovered then the patch may be dropped or reverted.
You may get further e-mails resulting from automated or manual testing and review of the tree, please engage with people reporting problems and send followup patches addressing any issues that are reported if needed.
If any updates are required or you are submitting further changes they should be sent as incremental updates against current git, existing patches will not be replaced.
Please add any relevant lists and maintainers to the CCs when replying to this mail.
Thanks, Mark
From ce99319a182fe766be67f96338386f3ec73e321c Mon Sep 17 00:00:00 2001
From: Maxime Chevallier maxime.chevallier@bootlin.com Date: Fri, 2 Mar 2018 15:55:09 +0100 Subject: [PATCH] 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 --- drivers/spi/spi.c | 10 ++++++++-- 1 file 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
linux-stable-mirror@lists.linaro.org
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Greg KH -
Mark Brown -
Maxime Chevallier