dmaengine: ioat: Allocate correct size for descriptor chunk

dma_alloc_coherent() is called with a fixed SZ_2M size, but frees happen
with IOAT_CHUNK_SIZE. Recently, IOAT_CHUNK_SIZE was reduced to 512M but
the allocation did not change. To fix, change to using the
IOAT_CHUNK_SIZE define.

This was caught with the upcoming patchset for converting Intel platforms to the
dma-iommu implementation. It has a warning when the unmapped size differs from
the mapped size.

Fixes: a02254f ("dmaengine: ioat: Decreasing allocation chunk size 2M->512K")
Suggested-by: Robin Murphy <[email protected]>
Signed-off-by: Logan Gunthorpe <[email protected]>
Acked-by: Dave Jiang <[email protected]>
Cc: Vinod Koul <[email protected]>
Cc: Dave Jiang <[email protected]>
Cc: Dan Williams <[email protected]>
Link: https://lore.kernel.org/intel-gfx/[email protected]/
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Vinod Koul <[email protected]>

Author: lsgunth

drivers/dma/ioat/dma.c

@@ -389,7 +389,7 @@ ioat_alloc_ring(struct dma_chan *c, int order, gfp_t flags)
 		struct ioat_descs *descs = &ioat_chan->descs[i];
 
 		descs->virt = dma_alloc_coherent(to_dev(ioat_chan),
-						 SZ_2M, &descs->hw, flags);
+					IOAT_CHUNK_SIZE, &descs->hw, flags);
 		if (!descs->virt) {
 			int idx;