[PATCH] lib/dma-debug.c: fix __hash_bucket_find

From: Ming Lei
Date: Thu Oct 18 2012 - 11:38:37 EST

If there is only one match, the unique matched entry should be returned.

Without the fix, the commit f62566214fe31c9f9b3218a42f1b19e6a9e6844a

dma-debug: new interfaces to debug dma mapping errors

can't work reliably because only device and dma_addr are passed to

Cc: Joerg Roedel <joerg.roedel@xxxxxxx>
Cc: Shuah Khan <shuah.khan@xxxxxx>
Cc: Paul Gortmaker <paul.gortmaker@xxxxxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Jakub Kicinski <kubakici@xxxxx>
Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxxxxx>
lib/dma-debug.c | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/lib/dma-debug.c b/lib/dma-debug.c
index 94aa94e..be132f3 100644
--- a/lib/dma-debug.c
+++ b/lib/dma-debug.c
@@ -283,6 +283,10 @@ static struct dma_debug_entry *__hash_bucket_find(struct hash_bucket *bucket,
if (!match(ref, entry))

+ /* record the first match */
+ if (!ret)
+ ret = entry;
* Some drivers map the same physical address multiple
* times. Without a hardware IOMMU this results in the

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