1 files changed, 34 insertions, 14 deletions

diff --git a/drivers/infiniband/hw/ipath/ipath_cq.c b/drivers/infiniband/hw/ipath/ipath_cq.c
index 049221bc590..87462e0cb4d 100644
--- a/drivers/infiniband/hw/ipath/ipath_cq.c
+++ b/drivers/infiniband/hw/ipath/ipath_cq.c
@@ -46,7 +46,7 @@
  */
 void ipath_cq_enter(struct ipath_cq *cq, struct ib_wc *entry, int solicited)
 {
-	struct ipath_cq_wc *wc = cq->queue;
+	struct ipath_cq_wc *wc;
 	unsigned long flags;
 	u32 head;
 	u32 next;
@@ -57,6 +57,7 @@ void ipath_cq_enter(struct ipath_cq *cq, struct ib_wc *entry, int solicited)
 	 * Note that the head pointer might be writable by user processes.
 	 * Take care to verify it is a sane value.
 	 */
+	wc = cq->queue;
 	head = wc->head;
 	if (head >= (unsigned) cq->ibcq.cqe) {
 		head = cq->ibcq.cqe;
@@ -109,21 +110,27 @@ void ipath_cq_enter(struct ipath_cq *cq, struct ib_wc *entry, int solicited)
 int ipath_poll_cq(struct ib_cq *ibcq, int num_entries, struct ib_wc *entry)
 {
 	struct ipath_cq *cq = to_icq(ibcq);
-	struct ipath_cq_wc *wc = cq->queue;
+	struct ipath_cq_wc *wc;
 	unsigned long flags;
 	int npolled;
+	u32 tail;
 
 	spin_lock_irqsave(&cq->lock, flags);
 
+	wc = cq->queue;
+	tail = wc->tail;
+	if (tail > (u32) cq->ibcq.cqe)
+		tail = (u32) cq->ibcq.cqe;
 	for (npolled = 0; npolled < num_entries; ++npolled, ++entry) {
-		if (wc->tail == wc->head)
+		if (tail == wc->head)
 			break;
-		*entry = wc->queue[wc->tail];
-		if (wc->tail >= cq->ibcq.cqe)
-			wc->tail = 0;
+		*entry = wc->queue[tail];
+		if (tail >= cq->ibcq.cqe)
+			tail = 0;
 		else
-			wc->tail++;
+			tail++;
 	}
+	wc->tail = tail;
 
 	spin_unlock_irqrestore(&cq->lock, flags);
 
@@ -177,11 +184,6 @@ struct ib_cq *ipath_create_cq(struct ib_device *ibdev, int entries,
 		goto done;
 	}
 
-	if (dev->n_cqs_allocated == ib_ipath_max_cqs) {
-		ret = ERR_PTR(-ENOMEM);
-		goto done;
-	}
-
 	/* Allocate the completion queue structure. */
 	cq = kmalloc(sizeof(*cq), GFP_KERNEL);
 	if (!cq) {
@@ -237,6 +239,16 @@ struct ib_cq *ipath_create_cq(struct ib_device *ibdev, int entries,
 	} else
 		cq->ip = NULL;
 
+	spin_lock(&dev->n_cqs_lock);
+	if (dev->n_cqs_allocated == ib_ipath_max_cqs) {
+		spin_unlock(&dev->n_cqs_lock);
+		ret = ERR_PTR(-ENOMEM);
+		goto bail_wc;
+	}
+
+	dev->n_cqs_allocated++;
+	spin_unlock(&dev->n_cqs_lock);
+
 	/*
 	 * ib_create_cq() will initialize cq->ibcq except for cq->ibcq.cqe.
 	 * The number of entries should be >= the number requested or return
@@ -253,7 +265,6 @@ struct ib_cq *ipath_create_cq(struct ib_device *ibdev, int entries,
 
 	ret = &cq->ibcq;
 
-	dev->n_cqs_allocated++;
 	goto done;
 
 bail_wc:
@@ -280,7 +291,9 @@ int ipath_destroy_cq(struct ib_cq *ibcq)
 	struct ipath_cq *cq = to_icq(ibcq);
 
 	tasklet_kill(&cq->comptask);
+	spin_lock(&dev->n_cqs_lock);
 	dev->n_cqs_allocated--;
+	spin_unlock(&dev->n_cqs_lock);
 	if (cq->ip)
 		kref_put(&cq->ip->ref, ipath_release_mmap_info);
 	else
@@ -316,10 +329,16 @@ int ipath_req_notify_cq(struct ib_cq *ibcq, enum ib_cq_notify notify)
 	return 0;
 }
 
+/**
+ * ipath_resize_cq - change the size of the CQ
+ * @ibcq: the completion queue
+ *
+ * Returns 0 for success.
+ */
 int ipath_resize_cq(struct ib_cq *ibcq, int cqe, struct ib_udata *udata)
 {
 	struct ipath_cq *cq = to_icq(ibcq);
-	struct ipath_cq_wc *old_wc = cq->queue;
+	struct ipath_cq_wc *old_wc;
 	struct ipath_cq_wc *wc;
 	u32 head, tail, n;
 	int ret;
@@ -355,6 +374,7 @@ int ipath_resize_cq(struct ib_cq *ibcq, int cqe, struct ib_udata *udata)
 	 * Make sure head and tail are sane since they
 	 * might be user writable.
 	 */
+	old_wc = cq->queue;
 	head = old_wc->head;
 	if (head > (u32) cq->ibcq.cqe)
 		head = (u32) cq->ibcq.cqe;