diff options
| author | Krishna Kumar <krkumar2@in.ibm.com> | 2006-11-24 16:03:48 +0530 |
|---|---|---|
| committer | Roland Dreier <rolandd@cisco.com> | 2006-11-29 15:33:08 -0800 |
| commit | c9edea298e52faeb0d4ae875cb712a5d69ba1966 (patch) | |
| tree | 9f89af31110b7ad8acce86fabb10c98005dedb75 | |
| parent | 7013696a5f5ccd0d847d5e8b841d0b0b312277c8 (diff) | |
RDMA/amso1100: Prevent deadlock in destroy QP
It is possible to swap the CQs used for send_cq and recv_cq when
creating two different QPs. If these two QPs are then destroyed at
the same time, an AB-BA deadlock can occur because the CQ locks are
taken our of order. Fix this by always taking CQ locks in a fixed
order.
Signed-off-by: Krishna Kumar <krkumar2@in.ibm.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>
| -rw-r--r-- | drivers/infiniband/hw/amso1100/c2_qp.c | 36 |
1 files changed, 28 insertions, 8 deletions
diff --git a/drivers/infiniband/hw/amso1100/c2_qp.c b/drivers/infiniband/hw/amso1100/c2_qp.c index 5bcf697aa33..179d005ed4a 100644 --- a/drivers/infiniband/hw/amso1100/c2_qp.c +++ b/drivers/infiniband/hw/amso1100/c2_qp.c @@ -564,6 +564,32 @@ int c2_alloc_qp(struct c2_dev *c2dev, return err; } +static inline void c2_lock_cqs(struct c2_cq *send_cq, struct c2_cq *recv_cq) +{ + if (send_cq == recv_cq) + spin_lock_irq(&send_cq->lock); + else if (send_cq > recv_cq) { + spin_lock_irq(&send_cq->lock); + spin_lock_nested(&recv_cq->lock, SINGLE_DEPTH_NESTING); + } else { + spin_lock_irq(&recv_cq->lock); + spin_lock_nested(&send_cq->lock, SINGLE_DEPTH_NESTING); + } +} + +static inline void c2_unlock_cqs(struct c2_cq *send_cq, struct c2_cq *recv_cq) +{ + if (send_cq == recv_cq) + spin_unlock_irq(&send_cq->lock); + else if (send_cq > recv_cq) { + spin_unlock(&recv_cq->lock); + spin_unlock_irq(&send_cq->lock); + } else { + spin_unlock(&send_cq->lock); + spin_unlock_irq(&recv_cq->lock); + } +} + void c2_free_qp(struct c2_dev *c2dev, struct c2_qp *qp) { struct c2_cq *send_cq; @@ -576,15 +602,9 @@ void c2_free_qp(struct c2_dev *c2dev, struct c2_qp *qp) * Lock CQs here, so that CQ polling code can do QP lookup * without taking a lock. */ - spin_lock_irq(&send_cq->lock); - if (send_cq != recv_cq) - spin_lock(&recv_cq->lock); - + c2_lock_cqs(send_cq, recv_cq); c2_free_qpn(c2dev, qp->qpn); - - if (send_cq != recv_cq) - spin_unlock(&recv_cq->lock); - spin_unlock_irq(&send_cq->lock); + c2_unlock_cqs(send_cq, recv_cq); /* * Destory qp in the rnic... |