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authorJoerg Roedel <jroedel@suse.de>2019-02-07 12:59:15 +0100
committerMichael S. Tsirkin <mst@redhat.com>2019-03-06 11:19:11 -0500
commit133d624b1cee16906134e92d5befb843b58bcf31 (patch)
treeb5d5d7d1ce51dca0a90402227028eee5ded9ba6b /kernel
parent492366f7b4237257ef50ca9c431a6a0d50225aca (diff)
downloadlinux-133d624b1cee16906134e92d5befb843b58bcf31.tar.bz2
dma: Introduce dma_max_mapping_size()
The function returns the maximum size that can be mapped using DMA-API functions. The patch also adds the implementation for direct DMA and a new dma_map_ops pointer so that other implementations can expose their limit. Cc: stable@vger.kernel.org Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Joerg Roedel <jroedel@suse.de> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/dma/direct.c11
-rw-r--r--kernel/dma/mapping.c14
2 files changed, 25 insertions, 0 deletions
diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index 355d16acee6d..6310ad01f915 100644
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -380,3 +380,14 @@ int dma_direct_supported(struct device *dev, u64 mask)
*/
return mask >= __phys_to_dma(dev, min_mask);
}
+
+size_t dma_direct_max_mapping_size(struct device *dev)
+{
+ size_t size = SIZE_MAX;
+
+ /* If SWIOTLB is active, use its maximum mapping size */
+ if (is_swiotlb_active())
+ size = swiotlb_max_mapping_size(dev);
+
+ return size;
+}
diff --git a/kernel/dma/mapping.c b/kernel/dma/mapping.c
index a11006b6d8e8..5753008ab286 100644
--- a/kernel/dma/mapping.c
+++ b/kernel/dma/mapping.c
@@ -357,3 +357,17 @@ void dma_cache_sync(struct device *dev, void *vaddr, size_t size,
ops->cache_sync(dev, vaddr, size, dir);
}
EXPORT_SYMBOL(dma_cache_sync);
+
+size_t dma_max_mapping_size(struct device *dev)
+{
+ const struct dma_map_ops *ops = get_dma_ops(dev);
+ size_t size = SIZE_MAX;
+
+ if (dma_is_direct(ops))
+ size = dma_direct_max_mapping_size(dev);
+ else if (ops && ops->max_mapping_size)
+ size = ops->max_mapping_size(dev);
+
+ return size;
+}
+EXPORT_SYMBOL_GPL(dma_max_mapping_size);