IB/qib: Remove qib_lookup_qpn and use rvt_lookup_qpn instead

Add calls to rcu_read_lock()/rcu_read_unlock() as rvt_lookup_qpn callers
must hold the rcu_read_lock before calling and keep the lock until the
returned qp is no longer in use.

Remove lookaside qp and some qp refcount atomics in the sdma send code
that is redundant with the s_dma_busy refcount, which will also stall
the state processing to the reset state.

Change the qpn hash function to hash_32 which is hash function used
in rvt_lookup_qpn. qpn_hash function would be eliminated in later patches.

Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Reviewed-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Harish Chegondi <harish.chegondi@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

1 files changed, 3 insertions, 39 deletions

diff --git a/drivers/infiniband/hw/qib/qib_qp.c b/drivers/infiniband/hw/qib/qib_qp.c
index ce9002f6e7a2..8508e69f530c 100644
--- a/drivers/infiniband/hw/qib/qib_qp.c
+++ b/drivers/infiniband/hw/qib/qib_qp.c
@@ -34,7 +34,6 @@
 
 #include <linux/err.h>
 #include <linux/vmalloc.h>
-#include <linux/jhash.h>
 #include <rdma/rdma_vt.h>
 #ifdef CONFIG_DEBUG_FS
 #include <linux/seq_file.h>
@@ -221,8 +220,7 @@ static void free_qpn(struct rvt_qpn_table *qpt, u32 qpn)
 
 static inline unsigned qpn_hash(struct qib_ibdev *dev, u32 qpn)
 {
-	return jhash_1word(qpn, dev->qp_rnd) &
-		(dev->rdi.qp_dev->qp_table_size - 1);
+	return hash_32(qpn, dev->rdi.qp_dev->qp_table_bits);
 }
 
 
@@ -293,7 +291,8 @@ static void remove_qp(struct qib_ibdev *dev, struct rvt_qp *qp)
 	spin_unlock_irqrestore(&dev->rdi.qp_dev->qpt_lock, flags);
 	if (removed) {
 		synchronize_rcu();
-		atomic_dec(&qp->refcount);
+		if (atomic_dec_and_test(&qp->refcount))
+			wake_up(&qp->wait);
 	}
 }
 
@@ -320,41 +319,6 @@ unsigned qib_free_all_qps(struct rvt_dev_info *rdi)
 	return qp_inuse;
 }
 
-/**
- * qib_lookup_qpn - return the QP with the given QPN
- * @qpt: the QP table
- * @qpn: the QP number to look up
- *
- * The caller is responsible for decrementing the QP reference count
- * when done.
- */
-struct rvt_qp *qib_lookup_qpn(struct qib_ibport *ibp, u32 qpn)
-{
-	struct rvt_qp *qp = NULL;
-
-	rcu_read_lock();
-	if (unlikely(qpn <= 1)) {
-		if (qpn == 0)
-			qp = rcu_dereference(ibp->rvp.qp[0]);
-		else
-			qp = rcu_dereference(ibp->rvp.qp[1]);
-		if (qp)
-			atomic_inc(&qp->refcount);
-	} else {
-		struct qib_ibdev *dev = &ppd_from_ibp(ibp)->dd->verbs_dev;
-		unsigned n = qpn_hash(dev, qpn);
-
-		for (qp = rcu_dereference(dev->rdi.qp_dev->qp_table[n]); qp;
-			qp = rcu_dereference(qp->next))
-			if (qp->ibqp.qp_num == qpn) {
-				atomic_inc(&qp->refcount);
-				break;
-			}
-	}
-	rcu_read_unlock();
-	return qp;
-}
-
 void notify_qp_reset(struct rvt_qp *qp)
 {
 	struct qib_qp_priv *priv = qp->priv;