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authorRobin Murphy <robin.murphy@arm.com>2015-11-07 03:32:51 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2015-11-07 04:50:42 +0300
commit002edb6f6f2a79bea50de11260ddc9572e6db731 (patch)
tree045566a75985092e4044a30b5b2363a6e7c92583 /include/linux/dma-mapping.h
parent8639b46139b0e4ea3b1ab1c274e410ee327f1d89 (diff)
downloadlinux-002edb6f6f2a79bea50de11260ddc9572e6db731.tar.xz
dma-mapping: tidy up dma_parms default handling
Many DMA controllers and other devices set max_segment_size to indicate their scatter-gather capability, but have no interest in segment_boundary_mask. However, the existence of a dma_parms structure precludes the use of any default value, leaving them as zeros (assuming a properly kzalloc'ed structure). If a well-behaved IOMMU (or SWIOTLB) then tries to respect this by ensuring a mapped segment does not cross a zero-byte boundary, hilarity ensues. Since zero is a nonsensical value for either parameter, treat it as an indicator for "default", as might be expected. In the process, clean up a bit by replacing the bare constants with slightly more meaningful macros and removing the superfluous "else" statements. [akpm@linux-foundation.org: dma-mapping.h needs sizes.h for SZ_64K] Signed-off-by: Robin Murphy <robin.murphy@arm.com> Reviewed-by: Sumit Semwal <sumit.semwal@linaro.org> Acked-by: Marek Szyprowski <m.szyprowski@samsung.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Sakari Ailus <sakari.ailus@iki.fi> Cc: Russell King <rmk+kernel@arm.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/dma-mapping.h')
-rw-r--r--include/linux/dma-mapping.h18
1 files changed, 11 insertions, 7 deletions
diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
index ac07ff090919..2e551e2d2d03 100644
--- a/include/linux/dma-mapping.h
+++ b/include/linux/dma-mapping.h
@@ -1,6 +1,7 @@
#ifndef _LINUX_DMA_MAPPING_H
#define _LINUX_DMA_MAPPING_H
+#include <linux/sizes.h>
#include <linux/string.h>
#include <linux/device.h>
#include <linux/err.h>
@@ -145,7 +146,9 @@ static inline void arch_teardown_dma_ops(struct device *dev) { }
static inline unsigned int dma_get_max_seg_size(struct device *dev)
{
- return dev->dma_parms ? dev->dma_parms->max_segment_size : 65536;
+ if (dev->dma_parms && dev->dma_parms->max_segment_size)
+ return dev->dma_parms->max_segment_size;
+ return SZ_64K;
}
static inline unsigned int dma_set_max_seg_size(struct device *dev,
@@ -154,14 +157,15 @@ static inline unsigned int dma_set_max_seg_size(struct device *dev,
if (dev->dma_parms) {
dev->dma_parms->max_segment_size = size;
return 0;
- } else
- return -EIO;
+ }
+ return -EIO;
}
static inline unsigned long dma_get_seg_boundary(struct device *dev)
{
- return dev->dma_parms ?
- dev->dma_parms->segment_boundary_mask : 0xffffffff;
+ if (dev->dma_parms && dev->dma_parms->segment_boundary_mask)
+ return dev->dma_parms->segment_boundary_mask;
+ return DMA_BIT_MASK(32);
}
static inline int dma_set_seg_boundary(struct device *dev, unsigned long mask)
@@ -169,8 +173,8 @@ static inline int dma_set_seg_boundary(struct device *dev, unsigned long mask)
if (dev->dma_parms) {
dev->dma_parms->segment_boundary_mask = mask;
return 0;
- } else
- return -EIO;
+ }
+ return -EIO;
}
#ifndef dma_max_pfn