ioat: cleanup completion status reads

The cleanup path makes an effort to only perform an atomic read of the
64-bit completion address.  However in the 32-bit case it does not
matter if we read the upper-32 and lower-32 non-atomically because the
upper-32 will always be zero.

Signed-off-by: Maciej Sosnowski <maciej.sosnowski@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

1 files changed, 2 insertions, 8 deletions

diff --git a/drivers/dma/ioat/dma.h b/drivers/dma/ioat/dma.h
index 9f9edc2cd07..5fd6e2de84d 100644
--- a/drivers/dma/ioat/dma.h
+++ b/drivers/dma/ioat/dma.h
@@ -96,14 +96,8 @@ struct ioat_chan_common {
         struct ioatdma_device *device;
         struct dma_chan common;
 
-        dma_addr_t completion_addr;
-        union {
-                u64 full; /* HW completion writeback */
-                struct {
-                        u32 low;
-                        u32 high;
-                };
-        } *completion_virt;
+        dma_addr_t completion_dma;
+        u64 *completion;
         unsigned long last_compl_desc_addr_hw;
         struct tasklet_struct cleanup_task;
 };