[patch 06/71] async_tx: fix the bug in async_tx_run_dependencies

[Greg KH]

2.6.26-stable review patch.  If anyone has any objections, please let us
know.

------------------
From: Yuri Tikhonov <yur@xxxxxxxxxxx>

commit de24125dd0a452bfd4502fc448e3534c5d2e87aa upstream

Should clear the next pointer of the TX if we are sure that the
next TX (say NXT) will be submitted to the channel too. Overwise,
we break the chain of descriptors, because we lose the information
about the next descriptor to run. So next time, when invoke
async_tx_run_dependencies() with TX, it's TX->next will be NULL, and
NXT will be never submitted.

Signed-off-by: Yuri Tikhonov <yur@xxxxxxxxxxx>
Signed-off-by: Ilya Yanok <yanok@xxxxxxxxxxx>
Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

---
 crypto/async_tx/async_tx.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/crypto/async_tx/async_tx.c
+++ b/crypto/async_tx/async_tx.c
@@ -136,7 +136,8 @@ async_tx_run_dependencies(struct dma_asy
 		spin_lock_bh(&next->lock);
 		next->parent = NULL;
 		_next = next->next;
-		next->next = NULL;
+		if (_next && _next->chan == chan)
+			next->next = NULL;
 		spin_unlock_bh(&next->lock);
 
 		next->tx_submit(next);

-- 
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