async_tx: fix the bug in async_tx_run_dependencies

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@emcraft.com>
Signed-off-by: Ilya Yanok <yanok@emcraft.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/crypto/async_tx/async_tx.c b/crypto/async_tx/async_tx.c
index c6e772fc5ccd93cd5caa9b3f63df5142b8002924..bfffb3d219630c07750717a9a728d4ed063e3761 100644 (file)
--- a/crypto/async_tx/async_tx.c
+++ b/crypto/async_tx/async_tx.c
@@ -136,7 +136,8 @@ async_tx_run_dependencies(struct dma_async_tx_descriptor *tx)
                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);