IB/qib: Fix QP RCU sparse warnings

Commit af061a644a0e ("IB/qib: Use RCU for qpn lookup") introduced sparse
warnings.

This patch corrects those issues.

Signed-off-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>

1 files changed, 24 insertions, 11 deletions

diff --git a/drivers/infiniband/hw/qib/qib_qp.c b/drivers/infiniband/hw/qib/qib_qp.c
index 693041b076f0..4850d03870c2 100644
--- a/drivers/infiniband/hw/qib/qib_qp.c
+++ b/drivers/infiniband/hw/qib/qib_qp.c
@@ -1,6 +1,6 @@
 /*
- * Copyright (c) 2006, 2007, 2008, 2009, 2010 QLogic Corporation.
- * All rights reserved.
+ * Copyright (c) 2012 Intel Corporation.  All rights reserved.
+ * Copyright (c) 2006 - 2012 QLogic Corporation.  * All rights reserved.
  * Copyright (c) 2005, 2006 PathScale, Inc. All rights reserved.
  *
  * This software is available to you under a choice of one of two
@@ -250,23 +250,33 @@ static void remove_qp(struct qib_ibdev *dev, struct qib_qp *qp)
 
         spin_lock_irqsave(&dev->qpt_lock, flags);
 
-        if (ibp->qp0 == qp) {
+        if (rcu_dereference_protected(ibp->qp0,
+                        lockdep_is_held(&dev->qpt_lock)) == qp) {
                 atomic_dec(&qp->refcount);
                 rcu_assign_pointer(ibp->qp0, NULL);
-        } else if (ibp->qp1 == qp) {
+        } else if (rcu_dereference_protected(ibp->qp1,
+                        lockdep_is_held(&dev->qpt_lock)) == qp) {
                 atomic_dec(&qp->refcount);
                 rcu_assign_pointer(ibp->qp1, NULL);
         } else {
-                struct qib_qp *q, **qpp;
+                struct qib_qp *q;
+                struct qib_qp __rcu **qpp;
 
                 qpp = &dev->qp_table[n];
-                for (; (q = *qpp) != NULL; qpp = &q->next)
+                q = rcu_dereference_protected(*qpp,
+                        lockdep_is_held(&dev->qpt_lock));
+                for (; q; qpp = &q->next) {
                         if (q == qp) {
                                 atomic_dec(&qp->refcount);
-                                rcu_assign_pointer(*qpp, qp->next);
-                                qp->next = NULL;
+                                *qpp = qp->next;
+                                rcu_assign_pointer(qp->next, NULL);
+                                q = rcu_dereference_protected(*qpp,
+                                        lockdep_is_held(&dev->qpt_lock));
                                 break;
                         }
+                        q = rcu_dereference_protected(*qpp,
+                                lockdep_is_held(&dev->qpt_lock));
+                }
         }
 
         spin_unlock_irqrestore(&dev->qpt_lock, flags);
@@ -302,10 +312,12 @@ unsigned qib_free_all_qps(struct qib_devdata *dd)
 
         spin_lock_irqsave(&dev->qpt_lock, flags);
         for (n = 0; n < dev->qp_table_size; n++) {
-                qp = dev->qp_table[n];
+                qp = rcu_dereference_protected(dev->qp_table[n],
+                        lockdep_is_held(&dev->qpt_lock));
                 rcu_assign_pointer(dev->qp_table[n], NULL);
 
-                for (; qp; qp = qp->next)
+                for (; qp; qp = rcu_dereference_protected(qp->next,
+                                        lockdep_is_held(&dev->qpt_lock)))
                         qp_inuse++;
         }
         spin_unlock_irqrestore(&dev->qpt_lock, flags);
@@ -337,7 +349,8 @@ struct qib_qp *qib_lookup_qpn(struct qib_ibport *ibp, u32 qpn)
                 unsigned n = qpn_hash(dev, qpn);
 
                 rcu_read_lock();
-                for (qp = dev->qp_table[n]; rcu_dereference(qp); qp = qp->next)
+                for (qp = rcu_dereference(dev->qp_table[n]); qp;
+                        qp = rcu_dereference(qp->next))
                         if (qp->ibqp.qp_num == qpn)
                                 break;
         }