IB/qib: Fix sparse RCU warnings in qib_keys.c

Commit 8aac4cc3 ("IB/qib: RCU locking for MR validation") introduced
new sparse warnings in qib_keys.c.
Acked-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>

drivers/infiniband/hw/qib/qib_keys.c

@@ -349,7 +349,9 @@ int qib_fast_reg_mr(struct qib_qp *qp, struct ib_send_wr *wr)
 	if (pd->user || rkey == 0)
 		goto bail;
 
-	mr = rkt->table[(rkey >> (32 - ib_qib_lkey_table_size))];
+	mr = rcu_dereference_protected(
+		rkt->table[(rkey >> (32 - ib_qib_lkey_table_size))],
+		lockdep_is_held(&rkt->lock));
 	if (unlikely(mr == NULL || qp->ibqp.pd != mr->pd))
 		goto bail;
 

drivers/infiniband/hw/qib/qib_verbs.h

@@ -650,7 +650,7 @@ struct qib_lkey_table {
 	u32 next;               /* next unused index (speeds search) */
 	u32 gen;                /* generation count */
 	u32 max;                /* size of the table */
-	struct qib_mregion **table;
+	struct qib_mregion __rcu **table;
 };
 
 struct qib_opcode_stats {
@@ -732,7 +732,7 @@ struct qib_ibdev {
 	struct list_head pending_mmaps;
 	spinlock_t mmap_offset_lock; /* protect mmap_offset */
 	u32 mmap_offset;
-	struct qib_mregion *dma_mr;
+	struct qib_mregion __rcu *dma_mr;
 
 	/* QP numbers are shared by all IB ports */
 	struct qib_qpn_table qpn_table;