IB/mthca: Make all device methods truly reentrant

Documentation/infiniband/core_locking.txt says:

  All of the methods in struct ib_device exported by a low-level
  driver must be fully reentrant.  The low-level driver is required to
  perform all synchronization necessary to maintain consistency, even
  if multiple function calls using the same object are run
  simultaneously.

However, mthca's modify_qp, modify_srq and resize_cq methods are
currently not reentrant.  Add a mutex to the QP, SRQ and CQ structures
so that these calls can be properly serialized.

Signed-off-by: Roland Dreier <rolandd@cisco.com>

1 files changed, 5 insertions, 0 deletions

diff --git a/drivers/infiniband/hw/mthca/mthca_srq.c b/drivers/infiniband/hw/mthca/mthca_srq.c
index b292fefa3b41..fab417c5cf43 100644
--- a/drivers/infiniband/hw/mthca/mthca_srq.c
+++ b/drivers/infiniband/hw/mthca/mthca_srq.c
@@ -243,6 +243,7 @@ int mthca_alloc_srq(struct mthca_dev *dev, struct mthca_pd *pd,
         spin_lock_init(&srq->lock);
         srq->refcount = 1;
         init_waitqueue_head(&srq->wait);
+        mutex_init(&srq->mutex);
 
         if (mthca_is_memfree(dev))
                 mthca_arbel_init_srq_context(dev, pd, srq, mailbox->buf);
@@ -371,7 +372,11 @@ int mthca_modify_srq(struct ib_srq *ibsrq, struct ib_srq_attr *attr,
         if (attr_mask & IB_SRQ_LIMIT) {
                 if (attr->srq_limit > srq->max)
                         return -EINVAL;
+
+                mutex_lock(&srq->mutex);
                 ret = mthca_ARM_SRQ(dev, srq->srqn, attr->srq_limit, &status);
+                mutex_unlock(&srq->mutex);
+
                 if (ret)
                         return ret;
                 if (status)