4 files changed, 48 insertions, 29 deletions

diff --git a/drivers/infiniband/hw/hfi1/file_ops.c b/drivers/infiniband/hw/hfi1/file_ops.c
index bef6946861b2..259115886d35 100644
--- a/drivers/infiniband/hw/hfi1/file_ops.c
+++ b/drivers/infiniband/hw/hfi1/file_ops.c
@@ -200,23 +200,24 @@ static int hfi1_file_open(struct inode *inode, struct file *fp)
 
 	fd = kzalloc(sizeof(*fd), GFP_KERNEL);
 
-	if (fd) {
-		fd->rec_cpu_num = -1; /* no cpu affinity by default */
-		fd->mm = current->mm;
-		mmgrab(fd->mm);
-		fd->dd = dd;
-		kobject_get(&fd->dd->kobj);
-		fp->private_data = fd;
-	} else {
-		fp->private_data = NULL;
-
-		if (atomic_dec_and_test(&dd->user_refcount))
-			complete(&dd->user_comp);
-
-		return -ENOMEM;
-	}
-
+	if (!fd || init_srcu_struct(&fd->pq_srcu))
+		goto nomem;
+	spin_lock_init(&fd->pq_rcu_lock);
+	spin_lock_init(&fd->tid_lock);
+	spin_lock_init(&fd->invalid_lock);
+	fd->rec_cpu_num = -1; /* no cpu affinity by default */
+	fd->mm = current->mm;
+	mmgrab(fd->mm);
+	fd->dd = dd;
+	kobject_get(&fd->dd->kobj);
+	fp->private_data = fd;
 	return 0;
+nomem:
+	kfree(fd);
+	fp->private_data = NULL;
+	if (atomic_dec_and_test(&dd->user_refcount))
+		complete(&dd->user_comp);
+	return -ENOMEM;
 }
 
 static long hfi1_file_ioctl(struct file *fp, unsigned int cmd,
@@ -301,21 +302,30 @@ static long hfi1_file_ioctl(struct file *fp, unsigned int cmd,
 static ssize_t hfi1_write_iter(struct kiocb *kiocb, struct iov_iter *from)
 {
 	struct hfi1_filedata *fd = kiocb->ki_filp->private_data;
-	struct hfi1_user_sdma_pkt_q *pq = fd->pq;
+	struct hfi1_user_sdma_pkt_q *pq;
 	struct hfi1_user_sdma_comp_q *cq = fd->cq;
 	int done = 0, reqs = 0;
 	unsigned long dim = from->nr_segs;
+	int idx;
 
-	if (!cq || !pq)
+	idx = srcu_read_lock(&fd->pq_srcu);
+	pq = srcu_dereference(fd->pq, &fd->pq_srcu);
+	if (!cq || !pq) {
+		srcu_read_unlock(&fd->pq_srcu, idx);
 		return -EIO;
+	}
 
-	if (!iter_is_iovec(from) || !dim)
+	if (!iter_is_iovec(from) || !dim) {
+		srcu_read_unlock(&fd->pq_srcu, idx);
 		return -EINVAL;
+	}
 
 	trace_hfi1_sdma_request(fd->dd, fd->uctxt->ctxt, fd->subctxt, dim);
 
-	if (atomic_read(&pq->n_reqs) == pq->n_max_reqs)
+	if (atomic_read(&pq->n_reqs) == pq->n_max_reqs) {
+		srcu_read_unlock(&fd->pq_srcu, idx);
 		return -ENOSPC;
+	}
 
 	while (dim) {
 		int ret;
@@ -333,6 +343,7 @@ static ssize_t hfi1_write_iter(struct kiocb *kiocb, struct iov_iter *from)
 		reqs++;
 	}
 
+	srcu_read_unlock(&fd->pq_srcu, idx);
 	return reqs;
 }
 
@@ -707,6 +718,7 @@ done:
 	if (atomic_dec_and_test(&dd->user_refcount))
 		complete(&dd->user_comp);
 
+	cleanup_srcu_struct(&fdata->pq_srcu);
 	kfree(fdata);
 	return 0;
 }
diff --git a/drivers/infiniband/hw/hfi1/hfi.h b/drivers/infiniband/hw/hfi1/hfi.h
index 6365e8ffed9d..cae12f416ca0 100644
--- a/drivers/infiniband/hw/hfi1/hfi.h
+++ b/drivers/infiniband/hw/hfi1/hfi.h
@@ -1444,10 +1444,13 @@ struct mmu_rb_handler;
 
 /* Private data for file operations */
 struct hfi1_filedata {
+	struct srcu_struct pq_srcu;
 	struct hfi1_devdata *dd;
 	struct hfi1_ctxtdata *uctxt;
 	struct hfi1_user_sdma_comp_q *cq;
-	struct hfi1_user_sdma_pkt_q *pq;
+	/* update side lock for SRCU */
+	spinlock_t pq_rcu_lock;
+	struct hfi1_user_sdma_pkt_q __rcu *pq;
 	u16 subctxt;
 	/* for cpu affinity; -1 if none */
 	int rec_cpu_num;
diff --git a/drivers/infiniband/hw/hfi1/user_exp_rcv.c b/drivers/infiniband/hw/hfi1/user_exp_rcv.c
index 2443423585b3..4da03f823474 100644
--- a/drivers/infiniband/hw/hfi1/user_exp_rcv.c
+++ b/drivers/infiniband/hw/hfi1/user_exp_rcv.c
@@ -87,9 +87,6 @@ int hfi1_user_exp_rcv_init(struct hfi1_filedata *fd,
 {
 	int ret = 0;
 
-	spin_lock_init(&fd->tid_lock);
-	spin_lock_init(&fd->invalid_lock);
-
 	fd->entry_to_rb = kcalloc(uctxt->expected_count,
 				  sizeof(struct rb_node *),
 				  GFP_KERNEL);
diff --git a/drivers/infiniband/hw/hfi1/user_sdma.c b/drivers/infiniband/hw/hfi1/user_sdma.c
index fd754a16475a..c2f0d9ba93de 100644
--- a/drivers/infiniband/hw/hfi1/user_sdma.c
+++ b/drivers/infiniband/hw/hfi1/user_sdma.c
@@ -179,7 +179,6 @@ 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 +235,7 @@ 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;
@@ -264,8 +263,14 @@ 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);
@@ -277,7 +282,8 @@ int hfi1_user_sdma_free_queues(struct hfi1_filedata *fd,
 		kfree(pq->req_in_use);
 		kmem_cache_destroy(pq->txreq_cache);
 		kfree(pq);
-		fd->pq = NULL;
+	} else {
+		spin_unlock(&fd->pq_rcu_lock);
 	}
 	if (fd->cq) {
 		vfree(fd->cq->comps);
@@ -321,7 +327,8 @@ 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;