Roland Dreier a19aa5c5fd IB/mthca: Fix potential AB-BA deadlock with CQ locks ... When destroying a QP, mthca locks both the QP's send CQ and receive CQ. However, the following scenario is perfectly valid: QP_a: send_cq == CQ_x, recv_cq == CQ_y QP_b: send_cq == CQ_y, recv_cq == CQ_x The old mthca code simply locked send_cq and then recv_cq, which in this case could lead to an AB-BA deadlock if QP_a and QP_b were destroyed simultaneously. We can fix this by changing the locking code to lock the CQ with the lower CQ number first, which will create a consistent lock ordering. Also, the second CQ is locked with spin_lock_nested() to tell lockdep that we know what we're doing with the lock nesting. This bug was found by lockdep. Signed-off-by: Roland Dreier <rolandd@cisco.com>		2006-08-11 08:56:57 -07:00
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ipath	IB/ipath: ipath_skip_sge() can break if num_sge > 1	2006-07-24 09:18:07 -07:00
mthca	IB/mthca: Fix potential AB-BA deadlock with CQ locks	2006-08-11 08:56:57 -07:00