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authorChristoph Hellwig <hch@lst.de>2020-06-29 15:03:56 +0200
committerDaniel Borkmann <daniel@iogearbox.net>2020-06-30 15:44:03 +0200
commit3aa91625007807bfca4155df1867a5c924a08662 (patch)
tree200b5d80ea2b377dcdc560056f1fc247dc18024f /kernel
parent2bdeb3ed547d8822b2566797afa6c2584abdb119 (diff)
downloadlinux-3aa91625007807bfca4155df1867a5c924a08662.tar.bz2
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
Diffstat (limited to 'kernel')
-rw-r--r--kernel/dma/direct.c6
-rw-r--r--kernel/dma/mapping.c10
2 files changed, 16 insertions, 0 deletions
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);