3 files changed, 37 insertions, 22 deletions

diff --git a/drivers/infiniband/hw/mlx5/main.c b/drivers/infiniband/hw/mlx5/main.c
index d9474b95d8e5..bd565af30d66 100644
--- a/drivers/infiniband/hw/mlx5/main.c
+++ b/drivers/infiniband/hw/mlx5/main.c
@@ -92,6 +92,12 @@ static LIST_HEAD(mlx5_ib_dev_list);
  */
 static DEFINE_MUTEX(mlx5_ib_multiport_mutex);
 
+/* We can't use an array for xlt_emergency_page because dma_map_single
+ * doesn't work on kernel modules memory
+ */
+static unsigned long xlt_emergency_page;
+static struct mutex xlt_emergency_page_mutex;
+
 struct mlx5_ib_dev *mlx5_ib_get_ibdev_from_mpi(struct mlx5_ib_multiport_info *mpi)
 {
 	struct mlx5_ib_dev *dev;
@@ -1698,17 +1704,10 @@ static struct ib_ucontext *mlx5_ib_alloc_ucontext(struct ib_device *ibdev,
 	context->ibucontext.invalidate_range = &mlx5_ib_invalidate_range;
 #endif
 
-	context->upd_xlt_page = __get_free_page(GFP_KERNEL);
-	if (!context->upd_xlt_page) {
-		err = -ENOMEM;
-		goto out_uars;
-	}
-	mutex_init(&context->upd_xlt_page_mutex);
-
 	if (MLX5_CAP_GEN(dev->mdev, log_max_transport_domain)) {
 		err = mlx5_ib_alloc_transport_domain(dev, &context->tdn);
 		if (err)
-			goto out_page;
+			goto out_uars;
 	}
 
 	INIT_LIST_HEAD(&context->vma_private_list);
@@ -1785,9 +1784,6 @@ out_td:
 	if (MLX5_CAP_GEN(dev->mdev, log_max_transport_domain))
 		mlx5_ib_dealloc_transport_domain(dev, context->tdn);
 
-out_page:
-	free_page(context->upd_xlt_page);
-
 out_uars:
 	deallocate_uars(dev, context);
 
@@ -1813,7 +1809,6 @@ static int mlx5_ib_dealloc_ucontext(struct ib_ucontext *ibcontext)
 	if (MLX5_CAP_GEN(dev->mdev, log_max_transport_domain))
 		mlx5_ib_dealloc_transport_domain(dev, context->tdn);
 
-	free_page(context->upd_xlt_page);
 	deallocate_uars(dev, context);
 	kfree(bfregi->sys_pages);
 	kfree(bfregi->count);
@@ -5292,13 +5287,32 @@ static struct mlx5_interface mlx5_ib_interface = {
 	.protocol	= MLX5_INTERFACE_PROTOCOL_IB,
 };
 
+unsigned long mlx5_ib_get_xlt_emergency_page(void)
+{
+	mutex_lock(&xlt_emergency_page_mutex);
+	return xlt_emergency_page;
+}
+
+void mlx5_ib_put_xlt_emergency_page(void)
+{
+	mutex_unlock(&xlt_emergency_page_mutex);
+}
+
 static int __init mlx5_ib_init(void)
 {
 	int err;
 
+	xlt_emergency_page = __get_free_page(GFP_KERNEL);
+	if (!xlt_emergency_page)
+		return -ENOMEM;
+
+	mutex_init(&xlt_emergency_page_mutex);
+
 	mlx5_ib_event_wq = alloc_ordered_workqueue("mlx5_ib_event_wq", 0);
-	if (!mlx5_ib_event_wq)
+	if (!mlx5_ib_event_wq) {
+		free_page(xlt_emergency_page);
 		return -ENOMEM;
+	}
 
 	mlx5_ib_odp_init();
 
@@ -5311,6 +5325,8 @@ static void __exit mlx5_ib_cleanup(void)
 {
 	mlx5_unregister_interface(&mlx5_ib_interface);
 	destroy_workqueue(mlx5_ib_event_wq);
+	mutex_destroy(&xlt_emergency_page_mutex);
+	free_page(xlt_emergency_page);
 }
 
 module_init(mlx5_ib_init);
diff --git a/drivers/infiniband/hw/mlx5/mlx5_ib.h b/drivers/infiniband/hw/mlx5/mlx5_ib.h
index e0bad28e0f09..d88c240c52ce 100644
--- a/drivers/infiniband/hw/mlx5/mlx5_ib.h
+++ b/drivers/infiniband/hw/mlx5/mlx5_ib.h
@@ -130,9 +130,6 @@ struct mlx5_ib_ucontext {
 	/* protect vma_private_list add/del */
 	struct mutex		vma_private_list_mutex;
 
-	unsigned long		upd_xlt_page;
-	/* protect ODP/KSM */
-	struct mutex		upd_xlt_page_mutex;
 	u64			lib_caps;
 };
 
@@ -1220,4 +1217,7 @@ static inline int get_num_static_uars(struct mlx5_ib_dev *dev,
 	return get_uars_per_sys_page(dev, bfregi->lib_uar_4k) * bfregi->num_static_sys_pages;
 }
 
+unsigned long mlx5_ib_get_xlt_emergency_page(void);
+void mlx5_ib_put_xlt_emergency_page(void);
+
 #endif /* MLX5_IB_H */
diff --git a/drivers/infiniband/hw/mlx5/mr.c b/drivers/infiniband/hw/mlx5/mr.c
index 820f93439b0c..87e8b3339ddd 100644
--- a/drivers/infiniband/hw/mlx5/mr.c
+++ b/drivers/infiniband/hw/mlx5/mr.c
@@ -985,7 +985,6 @@ int mlx5_ib_update_xlt(struct mlx5_ib_mr *mr, u64 idx, int npages,
 {
 	struct mlx5_ib_dev *dev = mr->dev;
 	struct device *ddev = dev->ib_dev.dev.parent;
-	struct mlx5_ib_ucontext *uctx = NULL;
 	int size;
 	void *xlt;
 	dma_addr_t dma;
@@ -1001,6 +1000,7 @@ int mlx5_ib_update_xlt(struct mlx5_ib_mr *mr, u64 idx, int npages,
 	size_t pages_to_map = 0;
 	size_t pages_iter = 0;
 	gfp_t gfp;
+	bool use_emergency_page = false;
 
 	/* UMR copies MTTs in units of MLX5_UMR_MTT_ALIGNMENT bytes,
 	 * so we need to align the offset and length accordingly
@@ -1027,12 +1027,11 @@ int mlx5_ib_update_xlt(struct mlx5_ib_mr *mr, u64 idx, int npages,
 	}
 
 	if (!xlt) {
-		uctx = to_mucontext(mr->ibmr.pd->uobject->context);
 		mlx5_ib_warn(dev, "Using XLT emergency buffer\n");
+		xlt = (void *)mlx5_ib_get_xlt_emergency_page();
 		size = PAGE_SIZE;
-		xlt = (void *)uctx->upd_xlt_page;
-		mutex_lock(&uctx->upd_xlt_page_mutex);
 		memset(xlt, 0, size);
+		use_emergency_page = true;
 	}
 	pages_iter = size / desc_size;
 	dma = dma_map_single(ddev, xlt, size, DMA_TO_DEVICE);
@@ -1096,8 +1095,8 @@ int mlx5_ib_update_xlt(struct mlx5_ib_mr *mr, u64 idx, int npages,
 	dma_unmap_single(ddev, dma, size, DMA_TO_DEVICE);
 
 free_xlt:
-	if (uctx)
-		mutex_unlock(&uctx->upd_xlt_page_mutex);
+	if (use_emergency_page)
+		mlx5_ib_put_xlt_emergency_page();
 	else
 		free_pages((unsigned long)xlt, get_order(size));