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>

5 files changed, 61 insertions, 35 deletions

diff --git a/drivers/infiniband/hw/qib/qib_iba7322.c b/drivers/infiniband/hw/qib/qib_iba7322.c
index c881e744c091..78e85503c509 100644
--- a/drivers/infiniband/hw/qib/qib_iba7322.c
+++ b/drivers/infiniband/hw/qib/qib_iba7322.c
@@ -1,5 +1,6 @@
 /*
- * Copyright (c) 2008, 2009, 2010 QLogic Corporation. All rights reserved.
+ * Copyright (c) 2012 Intel Corporation.  All rights reserved.
+ * Copyright (c) 2008 - 2012 QLogic Corporation. All rights reserved.
  *
  * This software is available to you under a choice of one of two
  * licenses.  You may choose to be licensed under the terms of the GNU
@@ -49,6 +50,7 @@
 #include "qib_qsfp.h"
 
 #include "qib_mad.h"
+#include "qib_verbs.h"
 
 static void qib_setup_7322_setextled(struct qib_pportdata *, u32);
 static void qib_7322_handle_hwerrors(struct qib_devdata *, char *, size_t);
@@ -5151,15 +5153,11 @@ static void try_7322_ipg(struct qib_pportdata *ppd)
                 goto retry;
 
         if (!ibp->smi_ah) {
-                struct ib_ah_attr attr;
                 struct ib_ah *ah;
 
-                memset(&attr, 0, sizeof attr);
-                attr.dlid = be16_to_cpu(IB_LID_PERMISSIVE);
-                attr.port_num = ppd->port;
-                ah = ib_create_ah(ibp->qp0->ibqp.pd, &attr);
+                ah = qib_create_qp0_ah(ibp, be16_to_cpu(IB_LID_PERMISSIVE));
                 if (IS_ERR(ah))
-                        ret = -EINVAL;
+                        ret = PTR_ERR(ah);
                 else {
                         send_buf->ah = ah;
                         ibp->smi_ah = to_iah(ah);
diff --git a/drivers/infiniband/hw/qib/qib_mad.c b/drivers/infiniband/hw/qib/qib_mad.c
index 43390217a026..6e20b58b90b6 100644
--- a/drivers/infiniband/hw/qib/qib_mad.c
+++ b/drivers/infiniband/hw/qib/qib_mad.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
@@ -90,14 +90,10 @@ static void qib_send_trap(struct qib_ibport *ibp, void *data, unsigned len)
         if (!ibp->sm_ah) {
                 if (ibp->sm_lid != be16_to_cpu(IB_LID_PERMISSIVE)) {
                         struct ib_ah *ah;
-                        struct ib_ah_attr attr;
 
-                        memset(&attr, 0, sizeof attr);
-                        attr.dlid = ibp->sm_lid;
-                        attr.port_num = ppd_from_ibp(ibp)->port;
-                        ah = ib_create_ah(ibp->qp0->ibqp.pd, &attr);
+                        ah = qib_create_qp0_ah(ibp, ibp->sm_lid);
                         if (IS_ERR(ah))
-                                ret = -EINVAL;
+                                ret = PTR_ERR(ah);
                         else {
                                 send_buf->ah = ah;
                                 ibp->sm_ah = to_iah(ah);
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;
         }
diff --git a/drivers/infiniband/hw/qib/qib_verbs.c b/drivers/infiniband/hw/qib/qib_verbs.c
index 59cdea345a82..03ace0650a8f 100644
--- a/drivers/infiniband/hw/qib/qib_verbs.c
+++ b/drivers/infiniband/hw/qib/qib_verbs.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
@@ -1845,6 +1845,23 @@ bail:
         return ret;
 }
 
+struct ib_ah *qib_create_qp0_ah(struct qib_ibport *ibp, u16 dlid)
+{
+        struct ib_ah_attr attr;
+        struct ib_ah *ah = ERR_PTR(-EINVAL);
+        struct qib_qp *qp0;
+
+        memset(&attr, 0, sizeof attr);
+        attr.dlid = dlid;
+        attr.port_num = ppd_from_ibp(ibp)->port;
+        rcu_read_lock();
+        qp0 = rcu_dereference(ibp->qp0);
+        if (qp0)
+                ah = ib_create_ah(qp0->ibqp.pd, &attr);
+        rcu_read_unlock();
+        return ah;
+}
+
 /**
  * qib_destroy_ah - destroy an address handle
  * @ibah: the AH to destroy
@@ -2060,7 +2077,7 @@ int qib_register_ib_device(struct qib_devdata *dd)
         spin_lock_init(&dev->lk_table.lock);
         dev->lk_table.max = 1 << ib_qib_lkey_table_size;
         lk_tab_size = dev->lk_table.max * sizeof(*dev->lk_table.table);
-        dev->lk_table.table = (struct qib_mregion **)
+        dev->lk_table.table = (struct qib_mregion __rcu **)
                 __get_free_pages(GFP_KERNEL, get_order(lk_tab_size));
         if (dev->lk_table.table == NULL) {
                 ret = -ENOMEM;
diff --git a/drivers/infiniband/hw/qib/qib_verbs.h b/drivers/infiniband/hw/qib/qib_verbs.h
index 1293133f28cb..61fad05328ca 100644
--- a/drivers/infiniband/hw/qib/qib_verbs.h
+++ b/drivers/infiniband/hw/qib/qib_verbs.h
@@ -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
@@ -420,7 +420,7 @@ struct qib_qp {
         /* read mostly fields above and below */
         struct ib_ah_attr remote_ah_attr;
         struct ib_ah_attr alt_ah_attr;
-        struct qib_qp *next;            /* link list for QPN hash table */
+        struct qib_qp __rcu *next;            /* link list for QPN hash table */
         struct qib_swqe *s_wq;  /* send work queue */
         struct qib_mmap_info *ip;
         struct qib_ib_header *s_hdr;     /* next packet header to send */
@@ -659,8 +659,8 @@ struct qib_opcode_stats {
 };
 
 struct qib_ibport {
-        struct qib_qp *qp0;
-        struct qib_qp *qp1;
+        struct qib_qp __rcu *qp0;
+        struct qib_qp __rcu *qp1;
         struct ib_mad_agent *send_agent;        /* agent for SMI (traps) */
         struct qib_ah *sm_ah;
         struct qib_ah *smi_ah;
@@ -743,7 +743,7 @@ struct qib_ibdev {
         struct list_head memwait;       /* list for wait kernel memory */
         struct list_head txreq_free;
         struct timer_list mem_timer;
-        struct qib_qp **qp_table;
+        struct qib_qp __rcu **qp_table;
         struct qib_pio_header *pio_hdrs;
         dma_addr_t pio_hdrs_phys;
         /* list of QPs waiting for RNR timer */
@@ -937,6 +937,8 @@ void qib_rc_rcv(struct qib_ctxtdata *rcd, struct qib_ib_header *hdr,
 
 int qib_check_ah(struct ib_device *ibdev, struct ib_ah_attr *ah_attr);
 
+struct ib_ah *qib_create_qp0_ah(struct qib_ibport *ibp, u16 dlid);
+
 void qib_rc_rnr_retry(unsigned long arg);
 
 void qib_rc_send_complete(struct qib_qp *qp, struct qib_ib_header *hdr);