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| author | Joerg Roedel <jroedel@suse.de> | 2019-02-07 12:59:14 +0100 |
|---|---|---|
| committer | Michael S. Tsirkin <mst@redhat.com> | 2019-03-06 17:19:06 +0100 |
| commit | 492366f7b4237257ef50ca9c431a6a0d50225aca (patch) | |
| tree | 7d867810eb10e65b5b5de8d1d569a89351127c7b /kernel/dma/swiotlb.c | |
| parent | swiotlb: Introduce swiotlb_max_mapping_size() (diff) | |
| download | linux-492366f7b4237257ef50ca9c431a6a0d50225aca.tar.xz linux-492366f7b4237257ef50ca9c431a6a0d50225aca.zip | |
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/swiotlb.c')
| -rw-r--r-- | kernel/dma/swiotlb.c | 9 |
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; +} |