forked from luck/tmp_suning_uos_patched
a19aa5c5fd
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>
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| .. | ||
| Kconfig | ||
| Makefile | ||
| mthca_allocator.c | ||
| mthca_av.c | ||
| mthca_catas.c | ||
| mthca_cmd.c | ||
| mthca_cmd.h | ||
| mthca_config_reg.h | ||
| mthca_cq.c | ||
| mthca_dev.h | ||
| mthca_doorbell.h | ||
| mthca_eq.c | ||
| mthca_mad.c | ||
| mthca_main.c | ||
| mthca_mcg.c | ||
| mthca_memfree.c | ||
| mthca_memfree.h | ||
| mthca_mr.c | ||
| mthca_pd.c | ||
| mthca_profile.c | ||
| mthca_profile.h | ||
| mthca_provider.c | ||
| mthca_provider.h | ||
| mthca_qp.c | ||
| mthca_reset.c | ||
| mthca_srq.c | ||
| mthca_uar.c | ||
| mthca_user.h | ||
| mthca_wqe.h | ||