Merge remote-tracking branch 'asoc/topic/max98090' into asoc-next

[firefly-linux-kernel-4.4.55.git] / lib / dma-debug.c

diff --git a/lib/dma-debug.c b/lib/dma-debug.c
index d3e06a5e981e91eb3b7800c598a79c17dfb44190..d87a17a819d07a58bc8f1dd40f2d41ae499935c8 100644 (file)
--- a/lib/dma-debug.c
+++ b/lib/dma-debug.c
@@ -1085,13 +1085,27 @@ void debug_dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
        ref.dev = dev;
        ref.dev_addr = dma_addr;
        bucket = get_hash_bucket(&ref, &flags);
-       entry = bucket_find_exact(bucket, &ref);
 
-       if (!entry)
-               goto out;
+       list_for_each_entry(entry, &bucket->list, list) {
+               if (!exact_match(&ref, entry))
+                       continue;
+
+               /*
+                * The same physical address can be mapped multiple
+                * times. Without a hardware IOMMU this results in the
+                * same device addresses being put into the dma-debug
+                * hash multiple times too. This can result in false
+                * positives being reported. Therefore we implement a
+                * best-fit algorithm here which updates the first entry
+                * from the hash which fits the reference value and is
+                * not currently listed as being checked.
+                */
+               if (entry->map_err_type == MAP_ERR_NOT_CHECKED) {
+                       entry->map_err_type = MAP_ERR_CHECKED;
+                       break;
+               }
+       }
 
-       entry->map_err_type = MAP_ERR_CHECKED;
-out:
        put_hash_bucket(bucket, &flags);
 }
 EXPORT_SYMBOL(debug_dma_mapping_error);