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| author | Nicolin Chen <nicoleotsuka@gmail.com> | 2020-09-02 00:16:46 +0200 |
|---|---|---|
| committer | Christoph Hellwig <hch@lst.de> | 2020-09-03 18:14:57 +0200 |
| commit | 135ba11a7a07b4ce9197d9fa4b196329a57f1e06 (patch) | |
| tree | 8ffbf80dc41135d70477e4e8dfe5a5ed92b6dde2 | |
| parent | dma-mapping: introduce dma_get_seg_boundary_nr_pages() (diff) | |
| download | linux-135ba11a7a07b4ce9197d9fa4b196329a57f1e06.tar.xz linux-135ba11a7a07b4ce9197d9fa4b196329a57f1e06.zip | |
dma-mapping: set default segment_boundary_mask to ULONG_MAX
The default segment_boundary_mask was set to DMA_BIT_MAKS(32)
a decade ago by referencing SCSI/block subsystem, as a 32-bit
mask was good enough for most of the devices.
Now more and more drivers set dma_masks above DMA_BIT_MAKS(32)
while only a handful of them call dma_set_seg_boundary(). This
means that most drivers have a 4GB segmention boundary because
DMA API returns a 32-bit default value, though they might not
really have such a limit.
The default segment_boundary_mask should mean "no limit" since
the device doesn't explicitly set the mask. But a 32-bit mask
certainly limits those devices capable of 32+ bits addressing.
So this patch sets default segment_boundary_mask to ULONG_MAX.
Signed-off-by: Nicolin Chen <nicoleotsuka@gmail.com>
Acked-by: Niklas Schnelle <schnelle@linux.ibm.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
| -rw-r--r-- | include/linux/dma-mapping.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h index faab0a8210b9..df0bff2ea750 100644 --- a/include/linux/dma-mapping.h +++ b/include/linux/dma-mapping.h @@ -629,7 +629,7 @@ static inline unsigned long dma_get_seg_boundary(struct device *dev) { if (dev->dma_parms && dev->dma_parms->segment_boundary_mask) return dev->dma_parms->segment_boundary_mask; - return DMA_BIT_MASK(32); + return ULONG_MAX; } /** |