diff options
| author | Christoph Hellwig <hch@lst.de> | 2020-06-29 15:03:56 +0200 |
|---|---|---|
| committer | Daniel Borkmann <daniel@iogearbox.net> | 2020-06-30 15:44:03 +0200 |
| commit | 3aa91625007807bfca4155df1867a5c924a08662 (patch) | |
| tree | 200b5d80ea2b377dcdc560056f1fc247dc18024f | |
| parent | 2bdeb3ed547d8822b2566797afa6c2584abdb119 (diff) | |
dma-mapping: Add a new dma_need_sync API
Add a new API to check if calls to dma_sync_single_for_{device,cpu} are
required for a given DMA streaming mapping.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20200629130359.2690853-2-hch@lst.de
| -rw-r--r-- | Documentation/core-api/dma-api.rst | 8 | ||||
| -rw-r--r-- | include/linux/dma-direct.h | 1 | ||||
| -rw-r--r-- | include/linux/dma-mapping.h | 5 | ||||
| -rw-r--r-- | kernel/dma/direct.c | 6 | ||||
| -rw-r--r-- | kernel/dma/mapping.c | 10 |
5 files changed, 30 insertions, 0 deletions
diff --git a/Documentation/core-api/dma-api.rst b/Documentation/core-api/dma-api.rst index 2d8d2fed7317..f41620439ef3 100644 --- a/Documentation/core-api/dma-api.rst +++ b/Documentation/core-api/dma-api.rst @@ -206,6 +206,14 @@ others should not be larger than the returned value. :: + bool + dma_need_sync(struct device *dev, dma_addr_t dma_addr); + +Returns %true if dma_sync_single_for_{device,cpu} calls are required to +transfer memory ownership. Returns %false if those calls can be skipped. + +:: + unsigned long dma_get_merge_boundary(struct device *dev); diff --git a/include/linux/dma-direct.h b/include/linux/dma-direct.h index 136f984df0d9..8b006730687b 100644 --- a/include/linux/dma-direct.h +++ b/include/linux/dma-direct.h @@ -87,4 +87,5 @@ int dma_direct_mmap(struct device *dev, struct vm_area_struct *vma, void *cpu_addr, dma_addr_t dma_addr, size_t size, unsigned long attrs); int dma_direct_supported(struct device *dev, u64 mask); +bool dma_direct_need_sync(struct device *dev, dma_addr_t dma_addr); #endif /* _LINUX_DMA_DIRECT_H */ diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h index 78f677cf45ab..a33ed3954ed4 100644 --- a/include/linux/dma-mapping.h +++ b/include/linux/dma-mapping.h @@ -461,6 +461,7 @@ int dma_set_mask(struct device *dev, u64 mask); int dma_set_coherent_mask(struct device *dev, u64 mask); u64 dma_get_required_mask(struct device *dev); size_t dma_max_mapping_size(struct device *dev); +bool dma_need_sync(struct device *dev, dma_addr_t dma_addr); unsigned long dma_get_merge_boundary(struct device *dev); #else /* CONFIG_HAS_DMA */ static inline dma_addr_t dma_map_page_attrs(struct device *dev, @@ -571,6 +572,10 @@ static inline size_t dma_max_mapping_size(struct device *dev) { return 0; } +static inline bool dma_need_sync(struct device *dev, dma_addr_t dma_addr) +{ + return false; +} static inline unsigned long dma_get_merge_boundary(struct device *dev) { return 0; diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c index 0a4881e59aa7..ecb922a0bfa0 100644 --- a/kernel/dma/direct.c +++ b/kernel/dma/direct.c @@ -530,3 +530,9 @@ size_t dma_direct_max_mapping_size(struct device *dev) return swiotlb_max_mapping_size(dev); return SIZE_MAX; } + +bool dma_direct_need_sync(struct device *dev, dma_addr_t dma_addr) +{ + return !dev_is_dma_coherent(dev) || + is_swiotlb_buffer(dma_to_phys(dev, dma_addr)); +} diff --git a/kernel/dma/mapping.c b/kernel/dma/mapping.c index 98e3d873792e..a8c18c9a796f 100644 --- a/kernel/dma/mapping.c +++ b/kernel/dma/mapping.c @@ -397,6 +397,16 @@ size_t dma_max_mapping_size(struct device *dev) } EXPORT_SYMBOL_GPL(dma_max_mapping_size); +bool dma_need_sync(struct device *dev, dma_addr_t dma_addr) +{ + const struct dma_map_ops *ops = get_dma_ops(dev); + + if (dma_is_direct(ops)) + return dma_direct_need_sync(dev, dma_addr); + return ops->sync_single_for_cpu || ops->sync_single_for_device; +} +EXPORT_SYMBOL_GPL(dma_need_sync); + unsigned long dma_get_merge_boundary(struct device *dev) { const struct dma_map_ops *ops = get_dma_ops(dev); |