2 files changed, 62 insertions, 2 deletions

diff --git a/drivers/staging/rdma/hfi1/user_sdma.c b/drivers/staging/rdma/hfi1/user_sdma.c
index bf55a41d151a..46e254d52dad 100644
--- a/drivers/staging/rdma/hfi1/user_sdma.c
+++ b/drivers/staging/rdma/hfi1/user_sdma.c
@@ -183,6 +183,8 @@ struct user_sdma_iovec {
 
 struct sdma_mmu_node {
 	struct mmu_rb_node rb;
+	struct list_head list;
+	struct hfi1_user_sdma_pkt_q *pq;
 	atomic_t refcount;
 	struct page **pages;
 	unsigned npages;
@@ -397,6 +399,8 @@ int hfi1_user_sdma_alloc_queues(struct hfi1_ctxtdata *uctxt, struct file *fp)
 	atomic_set(&pq->n_reqs, 0);
 	init_waitqueue_head(&pq->wait);
 	pq->sdma_rb_root = RB_ROOT;
+	INIT_LIST_HEAD(&pq->evict);
+	spin_lock_init(&pq->evict_lock);
 
 	iowait_init(&pq->busy, 0, NULL, defer_packet_queue,
 		    activate_packet_queue, NULL);
@@ -1027,9 +1031,33 @@ static inline int num_user_pages(const struct iovec *iov)
 	return 1 + ((epage - spage) >> PAGE_SHIFT);
 }
 
+/* Caller must hold pq->evict_lock */
+static u32 sdma_cache_evict(struct hfi1_user_sdma_pkt_q *pq, u32 npages)
+{
+	u32 cleared = 0;
+	struct sdma_mmu_node *node, *ptr;
+
+	list_for_each_entry_safe_reverse(node, ptr, &pq->evict, list) {
+		/* Make sure that no one is still using the node. */
+		if (!atomic_read(&node->refcount)) {
+			/*
+			 * Need to use the page count now as the remove callback
+			 * will free the node.
+			 */
+			cleared += node->npages;
+			spin_unlock(&pq->evict_lock);
+			hfi1_mmu_rb_remove(&pq->sdma_rb_root, &node->rb);
+			spin_lock(&pq->evict_lock);
+			if (cleared >= npages)
+				break;
+		}
+	}
+	return cleared;
+}
+
 static int pin_vector_pages(struct user_sdma_request *req,
 			    struct user_sdma_iovec *iovec) {
-	int ret = 0, pinned, npages;
+	int ret = 0, pinned, npages, cleared;
 	struct page **pages;
 	struct hfi1_user_sdma_pkt_q *pq = req->pq;
 	struct sdma_mmu_node *node = NULL;
@@ -1048,7 +1076,9 @@ static int pin_vector_pages(struct user_sdma_request *req,
 
 		node->rb.addr = (unsigned long)iovec->iov.iov_base;
 		node->rb.len = iovec->iov.iov_len;
+		node->pq = pq;
 		atomic_set(&node->refcount, 0);
+		INIT_LIST_HEAD(&node->list);
 	}
 
 	npages = num_user_pages(&iovec->iov);
@@ -1062,6 +1092,14 @@ static int pin_vector_pages(struct user_sdma_request *req,
 		memcpy(pages, node->pages, node->npages * sizeof(*pages));
 
 		npages -= node->npages;
+retry:
+		if (!hfi1_can_pin_pages(pq->dd, pq->n_locked, npages)) {
+			spin_lock(&pq->evict_lock);
+			cleared = sdma_cache_evict(pq, npages);
+			spin_unlock(&pq->evict_lock);
+			if (cleared >= npages)
+				goto retry;
+		}
 		pinned = hfi1_acquire_user_pages(
 			((unsigned long)iovec->iov.iov_base +
 			 (node->npages * PAGE_SIZE)), npages, 0,
@@ -1080,13 +1118,27 @@ static int pin_vector_pages(struct user_sdma_request *req,
 		node->pages = pages;
 		node->npages += pinned;
 		npages = node->npages;
+		spin_lock(&pq->evict_lock);
+		if (!rb_node)
+			list_add(&node->list, &pq->evict);
+		else
+			list_move(&node->list, &pq->evict);
+		pq->n_locked += pinned;
+		spin_unlock(&pq->evict_lock);
 	}
 	iovec->pages = node->pages;
 	iovec->npages = npages;
 
 	if (!rb_node) {
-		if (hfi1_mmu_rb_insert(&req->pq->sdma_rb_root, &node->rb))
+		ret = hfi1_mmu_rb_insert(&req->pq->sdma_rb_root, &node->rb);
+		if (ret) {
+			spin_lock(&pq->evict_lock);
+			list_del(&node->list);
+			pq->n_locked -= node->npages;
+			spin_unlock(&pq->evict_lock);
+			ret = 0;
 			goto bail;
+		}
 	} else {
 		atomic_inc(&node->refcount);
 	}
@@ -1503,6 +1555,11 @@ static void sdma_rb_remove(struct rb_root *root, struct mmu_rb_node *mnode,
 	struct sdma_mmu_node *node =
 		container_of(mnode, struct sdma_mmu_node, rb);
 
+	spin_lock(&node->pq->evict_lock);
+	list_del(&node->list);
+	node->pq->n_locked -= node->npages;
+	spin_unlock(&node->pq->evict_lock);
+
 	unpin_vector_pages(notifier ? NULL : current->mm, node->pages,
 			   node->npages);
 	/*
diff --git a/drivers/staging/rdma/hfi1/user_sdma.h b/drivers/staging/rdma/hfi1/user_sdma.h
index 39866b546523..b9240e351161 100644
--- a/drivers/staging/rdma/hfi1/user_sdma.h
+++ b/drivers/staging/rdma/hfi1/user_sdma.h
@@ -68,6 +68,9 @@ struct hfi1_user_sdma_pkt_q {
 	wait_queue_head_t wait;
 	unsigned long unpinned;
 	struct rb_root sdma_rb_root;
+	u32 n_locked;
+	struct list_head evict;
+	spinlock_t evict_lock; /* protect evict and n_locked */
 };
 
 struct hfi1_user_sdma_comp_q {