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authorJoerg Roedel2019-02-07 12:59:14 +0100
committerMichael S. Tsirkin2019-03-06 11:19:06 -0500
commit492366f7b4237257ef50ca9c431a6a0d50225aca (patch)
tree7d867810eb10e65b5b5de8d1d569a89351127c7b /kernel/dma
parentabe420bfae528c92bd8cc5ecb62dc95672b1fd6f (diff)
swiotlb: Add is_swiotlb_active() function
This function will be used from dma_direct code to determine the maximum segment size of a dma mapping. 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/dma')
-rw-r--r--kernel/dma/swiotlb.c9
1 files changed, 9 insertions, 0 deletions
diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index 9cb21259cb0b..c873f9cc2146 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -667,3 +667,12 @@ size_t swiotlb_max_mapping_size(struct device *dev)
{
return ((size_t)1 << IO_TLB_SHIFT) * IO_TLB_SEGSIZE;
}
+
+bool is_swiotlb_active(void)
+{
+ /*
+ * When SWIOTLB is initialized, even if io_tlb_start points to physical
+ * address zero, io_tlb_end surely doesn't.
+ */
+ return io_tlb_end != 0;
+}