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>

5 files changed, 48 insertions, 22 deletions

diff --git a/drivers/infiniband/hw/mthca/mthca_cq.c b/drivers/infiniband/hw/mthca/mthca_cq.c
index 87a8f1166a3b..3e27a084257e 100644
--- a/drivers/infiniband/hw/mthca/mthca_cq.c
+++ b/drivers/infiniband/hw/mthca/mthca_cq.c
@@ -822,6 +822,7 @@ int mthca_init_cq(struct mthca_dev *dev, int nent,
         spin_lock_init(&cq->lock);
         cq->refcount = 1;
         init_waitqueue_head(&cq->wait);
+        mutex_init(&cq->mutex);
 
         memset(cq_context, 0, sizeof *cq_context);
         cq_context->flags           = cpu_to_be32(MTHCA_CQ_STATUS_OK      |
diff --git a/drivers/infiniband/hw/mthca/mthca_provider.c b/drivers/infiniband/hw/mthca/mthca_provider.c
index 8f89ba7c9147..230ae21db8fd 100644
--- a/drivers/infiniband/hw/mthca/mthca_provider.c
+++ b/drivers/infiniband/hw/mthca/mthca_provider.c
@@ -793,18 +793,24 @@ static int mthca_resize_cq(struct ib_cq *ibcq, int entries, struct ib_udata *uda
         if (entries < 1 || entries > dev->limits.max_cqes)
                 return -EINVAL;
 
+        mutex_lock(&cq->mutex);
+
         entries = roundup_pow_of_two(entries + 1);
-        if (entries == ibcq->cqe + 1)
-                return 0;
+        if (entries == ibcq->cqe + 1) {
+                ret = 0;
+                goto out;
+        }
 
         if (cq->is_kernel) {
                 ret = mthca_alloc_resize_buf(dev, cq, entries);
                 if (ret)
-                        return ret;
+                        goto out;
                 lkey = cq->resize_buf->buf.mr.ibmr.lkey;
         } else {
-                if (ib_copy_from_udata(&ucmd, udata, sizeof ucmd))
-                        return -EFAULT;
+                if (ib_copy_from_udata(&ucmd, udata, sizeof ucmd)) {
+                        ret = -EFAULT;
+                        goto out;
+                }
                 lkey = ucmd.lkey;
         }
 
@@ -821,7 +827,7 @@ static int mthca_resize_cq(struct ib_cq *ibcq, int entries, struct ib_udata *uda
                         cq->resize_buf = NULL;
                         spin_unlock_irq(&cq->lock);
                 }
-                return ret;
+                goto out;
         }
 
         if (cq->is_kernel) {
@@ -848,7 +854,10 @@ static int mthca_resize_cq(struct ib_cq *ibcq, int entries, struct ib_udata *uda
         } else
                 ibcq->cqe = entries - 1;
 
-        return 0;
+out:
+        mutex_unlock(&cq->mutex);
+
+        return ret;
 }
 
 static int mthca_destroy_cq(struct ib_cq *cq)
diff --git a/drivers/infiniband/hw/mthca/mthca_provider.h b/drivers/infiniband/hw/mthca/mthca_provider.h
index 179a8f610d0f..8de2887ba15c 100644
--- a/drivers/infiniband/hw/mthca/mthca_provider.h
+++ b/drivers/infiniband/hw/mthca/mthca_provider.h
@@ -214,6 +214,7 @@ struct mthca_cq {
         int                     arm_sn;
 
         wait_queue_head_t       wait;
+        struct mutex            mutex;
 };
 
 struct mthca_srq {
@@ -237,6 +238,7 @@ struct mthca_srq {
         struct mthca_mr         mr;
 
         wait_queue_head_t       wait;
+        struct mutex            mutex;
 };
 
 struct mthca_wq {
@@ -278,6 +280,7 @@ struct mthca_qp {
         union mthca_buf        queue;
 
         wait_queue_head_t      wait;
+        struct mutex           mutex;
 };
 
 struct mthca_sqp {
diff --git a/drivers/infiniband/hw/mthca/mthca_qp.c b/drivers/infiniband/hw/mthca/mthca_qp.c
index 322bc32a93f6..16c387d8170c 100644
--- a/drivers/infiniband/hw/mthca/mthca_qp.c
+++ b/drivers/infiniband/hw/mthca/mthca_qp.c
@@ -536,6 +536,8 @@ int mthca_modify_qp(struct ib_qp *ibqp, struct ib_qp_attr *attr, int attr_mask)
         u8 status;
         int err = -EINVAL;
 
+        mutex_lock(&qp->mutex);
+
         if (attr_mask & IB_QP_CUR_STATE) {
                 cur_state = attr->cur_qp_state;
         } else {
@@ -553,39 +555,41 @@ int mthca_modify_qp(struct ib_qp *ibqp, struct ib_qp_attr *attr, int attr_mask)
                           "%d->%d with attr 0x%08x\n",
                           qp->transport, cur_state, new_state,
                           attr_mask);
-                return -EINVAL;
+                goto out;
         }
 
         if ((attr_mask & IB_QP_PKEY_INDEX) &&
              attr->pkey_index >= dev->limits.pkey_table_len) {
                 mthca_dbg(dev, "P_Key index (%u) too large. max is %d\n",
                           attr->pkey_index, dev->limits.pkey_table_len-1);
-                return -EINVAL;
+                goto out;
         }
 
         if ((attr_mask & IB_QP_PORT) &&
             (attr->port_num == 0 || attr->port_num > dev->limits.num_ports)) {
                 mthca_dbg(dev, "Port number (%u) is invalid\n", attr->port_num);
-                return -EINVAL;
+                goto out;
         }
 
         if (attr_mask & IB_QP_MAX_QP_RD_ATOMIC &&
             attr->max_rd_atomic > dev->limits.max_qp_init_rdma) {
                 mthca_dbg(dev, "Max rdma_atomic as initiator %u too large (max is %d)\n",
                           attr->max_rd_atomic, dev->limits.max_qp_init_rdma);
-                return -EINVAL;
+                goto out;
         }
 
         if (attr_mask & IB_QP_MAX_DEST_RD_ATOMIC &&
             attr->max_dest_rd_atomic > 1 << dev->qp_table.rdb_shift) {
                 mthca_dbg(dev, "Max rdma_atomic as responder %u too large (max %d)\n",
                           attr->max_dest_rd_atomic, 1 << dev->qp_table.rdb_shift);
-                return -EINVAL;
+                goto out;
         }
 
         mailbox = mthca_alloc_mailbox(dev, GFP_KERNEL);
-        if (IS_ERR(mailbox))
-                return PTR_ERR(mailbox);
+        if (IS_ERR(mailbox)) {
+                err = PTR_ERR(mailbox);
+                goto out;
+        }
         qp_param = mailbox->buf;
         qp_context = &qp_param->context;
         memset(qp_param, 0, sizeof *qp_param);
@@ -618,7 +622,7 @@ int mthca_modify_qp(struct ib_qp *ibqp, struct ib_qp_attr *attr, int attr_mask)
                 if (attr->path_mtu < IB_MTU_256 || attr->path_mtu > IB_MTU_2048) {
                         mthca_dbg(dev, "path MTU (%u) is invalid\n",
                                   attr->path_mtu);
-                        goto out;
+                        goto out_mailbox;
                 }
                 qp_context->mtu_msgmax = (attr->path_mtu << 5) | 31;
         }
@@ -672,7 +676,7 @@ int mthca_modify_qp(struct ib_qp *ibqp, struct ib_qp_attr *attr, int attr_mask)
         if (attr_mask & IB_QP_AV) {
                 if (mthca_path_set(dev, &attr->ah_attr, &qp_context->pri_path,
                                    attr_mask & IB_QP_PORT ? attr->port_num : qp->port))
-                        goto out;
+                        goto out_mailbox;
 
                 qp_param->opt_param_mask |= cpu_to_be32(MTHCA_QP_OPTPAR_PRIMARY_ADDR_PATH);
         }
@@ -686,18 +690,18 @@ int mthca_modify_qp(struct ib_qp *ibqp, struct ib_qp_attr *attr, int attr_mask)
                 if (attr->alt_pkey_index >= dev->limits.pkey_table_len) {
                         mthca_dbg(dev, "Alternate P_Key index (%u) too large. max is %d\n",
                                   attr->alt_pkey_index, dev->limits.pkey_table_len-1);
-                        goto out;
+                        goto out_mailbox;
                 }
 
                 if (attr->alt_port_num == 0 || attr->alt_port_num > dev->limits.num_ports) {
                         mthca_dbg(dev, "Alternate port number (%u) is invalid\n",
                                 attr->alt_port_num);
-                        goto out;
+                        goto out_mailbox;
                 }
 
                 if (mthca_path_set(dev, &attr->alt_ah_attr, &qp_context->alt_path,
                                    attr->alt_ah_attr.port_num))
-                        goto out;
+                        goto out_mailbox;
 
                 qp_context->alt_path.port_pkey |= cpu_to_be32(attr->alt_pkey_index |
                                                               attr->alt_port_num << 24);
@@ -793,12 +797,12 @@ int mthca_modify_qp(struct ib_qp *ibqp, struct ib_qp_attr *attr, int attr_mask)
         err = mthca_MODIFY_QP(dev, cur_state, new_state, qp->qpn, 0,
                               mailbox, sqd_event, &status);
         if (err)
-                goto out;
+                goto out_mailbox;
         if (status) {
                 mthca_warn(dev, "modify QP %d->%d returned status %02x.\n",
                            cur_state, new_state, status);
                 err = -EINVAL;
-                goto out;
+                goto out_mailbox;
         }
 
         qp->state = new_state;
@@ -853,8 +857,11 @@ int mthca_modify_qp(struct ib_qp *ibqp, struct ib_qp_attr *attr, int attr_mask)
                 }
         }
 
-out:
+out_mailbox:
         mthca_free_mailbox(dev, mailbox);
+
+out:
+        mutex_unlock(&qp->mutex);
         return err;
 }
 
@@ -1100,6 +1107,7 @@ static int mthca_alloc_qp_common(struct mthca_dev *dev,
 
         qp->refcount = 1;
         init_waitqueue_head(&qp->wait);
+        mutex_init(&qp->mutex);
         qp->state        = IB_QPS_RESET;
         qp->atomic_rd_en = 0;
         qp->resp_depth   = 0;
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)