1 files changed, 34 insertions, 12 deletions

diff --git a/drivers/infiniband/hw/hfi1/user_sdma.c b/drivers/infiniband/hw/hfi1/user_sdma.c
index fd754a16475a..a92346e88628 100644
--- a/drivers/infiniband/hw/hfi1/user_sdma.c
+++ b/drivers/infiniband/hw/hfi1/user_sdma.c
@@ -141,6 +141,7 @@ static int defer_packet_queue(
 	 */
 	xchg(&pq->state, SDMA_PKT_Q_DEFERRED);
 	if (list_empty(&pq->busy.list)) {
+		pq->busy.lock = &sde->waitlock;
 		iowait_get_priority(&pq->busy);
 		iowait_queue(pkts_sent, &pq->busy, &sde->dmawait);
 	}
@@ -155,6 +156,7 @@ static void activate_packet_queue(struct iowait *wait, int reason)
 {
 	struct hfi1_user_sdma_pkt_q *pq =
 		container_of(wait, struct hfi1_user_sdma_pkt_q, busy);
+	pq->busy.lock = NULL;
 	xchg(&pq->state, SDMA_PKT_Q_ACTIVE);
 	wake_up(&wait->wait_dma);
 };
@@ -179,7 +181,6 @@ int hfi1_user_sdma_alloc_queues(struct hfi1_ctxtdata *uctxt,
 	pq = kzalloc(sizeof(*pq), GFP_KERNEL);
 	if (!pq)
 		return -ENOMEM;
-
 	pq->dd = dd;
 	pq->ctxt = uctxt->ctxt;
 	pq->subctxt = fd->subctxt;
@@ -236,7 +237,7 @@ int hfi1_user_sdma_alloc_queues(struct hfi1_ctxtdata *uctxt,
 		goto pq_mmu_fail;
 	}
 
-	fd->pq = pq;
+	rcu_assign_pointer(fd->pq, pq);
 	fd->cq = cq;
 
 	return 0;
@@ -257,6 +258,21 @@ pq_reqs_nomem:
 	return ret;
 }
 
+static void flush_pq_iowait(struct hfi1_user_sdma_pkt_q *pq)
+{
+	unsigned long flags;
+	seqlock_t *lock = pq->busy.lock;
+
+	if (!lock)
+		return;
+	write_seqlock_irqsave(lock, flags);
+	if (!list_empty(&pq->busy.list)) {
+		list_del_init(&pq->busy.list);
+		pq->busy.lock = NULL;
+	}
+	write_sequnlock_irqrestore(lock, flags);
+}
+
 int hfi1_user_sdma_free_queues(struct hfi1_filedata *fd,
 			       struct hfi1_ctxtdata *uctxt)
 {
@@ -264,8 +280,14 @@ int hfi1_user_sdma_free_queues(struct hfi1_filedata *fd,
 
 	trace_hfi1_sdma_user_free_queues(uctxt->dd, uctxt->ctxt, fd->subctxt);
 
-	pq = fd->pq;
+	spin_lock(&fd->pq_rcu_lock);
+	pq = srcu_dereference_check(fd->pq, &fd->pq_srcu,
+				    lockdep_is_held(&fd->pq_rcu_lock));
 	if (pq) {
+		rcu_assign_pointer(fd->pq, NULL);
+		spin_unlock(&fd->pq_rcu_lock);
+		synchronize_srcu(&fd->pq_srcu);
+		/* at this point there can be no more new requests */
 		if (pq->handler)
 			hfi1_mmu_rb_unregister(pq->handler);
 		iowait_sdma_drain(&pq->busy);
@@ -276,8 +298,10 @@ int hfi1_user_sdma_free_queues(struct hfi1_filedata *fd,
 		kfree(pq->reqs);
 		kfree(pq->req_in_use);
 		kmem_cache_destroy(pq->txreq_cache);
+		flush_pq_iowait(pq);
 		kfree(pq);
-		fd->pq = NULL;
+	} else {
+		spin_unlock(&fd->pq_rcu_lock);
 	}
 	if (fd->cq) {
 		vfree(fd->cq->comps);
@@ -321,7 +345,8 @@ int hfi1_user_sdma_process_request(struct hfi1_filedata *fd,
 {
 	int ret = 0, i;
 	struct hfi1_ctxtdata *uctxt = fd->uctxt;
-	struct hfi1_user_sdma_pkt_q *pq = fd->pq;
+	struct hfi1_user_sdma_pkt_q *pq =
+		srcu_dereference(fd->pq, &fd->pq_srcu);
 	struct hfi1_user_sdma_comp_q *cq = fd->cq;
 	struct hfi1_devdata *dd = pq->dd;
 	unsigned long idx = 0;
@@ -564,10 +589,6 @@ int hfi1_user_sdma_process_request(struct hfi1_filedata *fd,
 
 	set_comp_state(pq, cq, info.comp_idx, QUEUED, 0);
 	pq->state = SDMA_PKT_Q_ACTIVE;
-	/* Send the first N packets in the request to buy us some time */
-	ret = user_sdma_send_pkts(req, pcount);
-	if (unlikely(ret < 0 && ret != -EBUSY))
-		goto free_req;
 
 	/*
 	 * This is a somewhat blocking send implementation.
@@ -580,11 +601,12 @@ int hfi1_user_sdma_process_request(struct hfi1_filedata *fd,
 		if (ret < 0) {
 			if (ret != -EBUSY)
 				goto free_req;
-			wait_event_interruptible_timeout(
+			if (wait_event_interruptible_timeout(
 				pq->busy.wait_dma,
-				(pq->state == SDMA_PKT_Q_ACTIVE),
+				pq->state == SDMA_PKT_Q_ACTIVE,
 				msecs_to_jiffies(
-					SDMA_IOWAIT_TIMEOUT));
+					SDMA_IOWAIT_TIMEOUT)) <= 0)
+				flush_pq_iowait(pq);
 		}
 	}
 	*count += idx;