net/mlx4: Avoid wrong virtual mappings

The dma_alloc_coherent() function returns a virtual address which can
be used for coherent access to the underlying memory.  On some
architectures, like arm64, undefined behavior results if this memory is
also accessed via virtual mappings that are not coherent.  Because of
their undefined nature, operations like virt_to_page() return garbage
when passed virtual addresses obtained from dma_alloc_coherent().  Any
subsequent mappings via vmap() of the garbage page values are unusable
and result in bad things like bus errors (synchronous aborts in ARM64
speak).

The mlx4 driver contains code that does the equivalent of:
vmap(virt_to_page(dma_alloc_coherent)), this results in an OOPs when the
device is opened.

Prevent Ethernet driver to run this problematic code by forcing it to
allocate contiguous memory. As for the Infiniband driver, at first we
are trying to allocate contiguous memory, but in case of failure roll
back to work with fragmented memory.

Signed-off-by: Haggai Abramovsky <hagaya@mellanox.com>
Signed-off-by: Yishai Hadas <yishaih@mellanox.com>
Reported-by: David Daney <david.daney@cavium.com>
Tested-by: Sinan Kaya <okaya@codeaurora.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

7 files changed, 45 insertions, 117 deletions

diff --git a/drivers/net/ethernet/mellanox/mlx4/alloc.c b/drivers/net/ethernet/mellanox/mlx4/alloc.c
index 0c51c69f802f..249a4584401a 100644
--- a/drivers/net/ethernet/mellanox/mlx4/alloc.c
+++ b/drivers/net/ethernet/mellanox/mlx4/alloc.c
@@ -576,41 +576,48 @@ out:
 
 	return res;
 }
-/*
- * Handling for queue buffers -- we allocate a bunch of memory and
- * register it in a memory region at HCA virtual address 0.  If the
- * requested size is > max_direct, we split the allocation into
- * multiple pages, so we don't require too much contiguous memory.
- */
 
-int mlx4_buf_alloc(struct mlx4_dev *dev, int size, int max_direct,
-		   struct mlx4_buf *buf, gfp_t gfp)
+static int mlx4_buf_direct_alloc(struct mlx4_dev *dev, int size,
+				 struct mlx4_buf *buf, gfp_t gfp)
 {
 	dma_addr_t t;
 
-	if (size <= max_direct) {
-		buf->nbufs        = 1;
-		buf->npages       = 1;
-		buf->page_shift   = get_order(size) + PAGE_SHIFT;
-		buf->direct.buf   = dma_alloc_coherent(&dev->persist->pdev->dev,
-						       size, &t, gfp);
-		if (!buf->direct.buf)
-			return -ENOMEM;
+	buf->nbufs        = 1;
+	buf->npages       = 1;
+	buf->page_shift   = get_order(size) + PAGE_SHIFT;
+	buf->direct.buf   =
+		dma_zalloc_coherent(&dev->persist->pdev->dev,
+				    size, &t, gfp);
+	if (!buf->direct.buf)
+		return -ENOMEM;
 
-		buf->direct.map = t;
+	buf->direct.map = t;
 
-		while (t & ((1 << buf->page_shift) - 1)) {
-			--buf->page_shift;
-			buf->npages *= 2;
-		}
+	while (t & ((1 << buf->page_shift) - 1)) {
+		--buf->page_shift;
+		buf->npages *= 2;
+	}
 
-		memset(buf->direct.buf, 0, size);
+	return 0;
+}
+
+/* Handling for queue buffers -- we allocate a bunch of memory and
+ * register it in a memory region at HCA virtual address 0. If the
+ *  requested size is > max_direct, we split the allocation into
+ *  multiple pages, so we don't require too much contiguous memory.
+ */
+int mlx4_buf_alloc(struct mlx4_dev *dev, int size, int max_direct,
+		   struct mlx4_buf *buf, gfp_t gfp)
+{
+	if (size <= max_direct) {
+		return mlx4_buf_direct_alloc(dev, size, buf, gfp);
 	} else {
+		dma_addr_t t;
 		int i;
 
-		buf->direct.buf  = NULL;
-		buf->nbufs       = (size + PAGE_SIZE - 1) / PAGE_SIZE;
-		buf->npages      = buf->nbufs;
+		buf->direct.buf = NULL;
+		buf->nbufs	= (size + PAGE_SIZE - 1) / PAGE_SIZE;
+		buf->npages	= buf->nbufs;
 		buf->page_shift  = PAGE_SHIFT;
 		buf->page_list   = kcalloc(buf->nbufs, sizeof(*buf->page_list),
 					   gfp);
@@ -619,28 +626,12 @@ int mlx4_buf_alloc(struct mlx4_dev *dev, int size, int max_direct,
 
 		for (i = 0; i < buf->nbufs; ++i) {
 			buf->page_list[i].buf =
-				dma_alloc_coherent(&dev->persist->pdev->dev,
-						   PAGE_SIZE,
-						   &t, gfp);
+				dma_zalloc_coherent(&dev->persist->pdev->dev,
+						    PAGE_SIZE, &t, gfp);
 			if (!buf->page_list[i].buf)
 				goto err_free;
 
 			buf->page_list[i].map = t;
-
-			memset(buf->page_list[i].buf, 0, PAGE_SIZE);
-		}
-
-		if (BITS_PER_LONG == 64) {
-			struct page **pages;
-			pages = kmalloc(sizeof *pages * buf->nbufs, gfp);
-			if (!pages)
-				goto err_free;
-			for (i = 0; i < buf->nbufs; ++i)
-				pages[i] = virt_to_page(buf->page_list[i].buf);
-			buf->direct.buf = vmap(pages, buf->nbufs, VM_MAP, PAGE_KERNEL);
-			kfree(pages);
-			if (!buf->direct.buf)
-				goto err_free;
 		}
 	}
 
@@ -655,15 +646,11 @@ EXPORT_SYMBOL_GPL(mlx4_buf_alloc);
 
 void mlx4_buf_free(struct mlx4_dev *dev, int size, struct mlx4_buf *buf)
 {
-	int i;
-
-	if (buf->nbufs == 1)
+	if (buf->nbufs == 1) {
 		dma_free_coherent(&dev->persist->pdev->dev, size,
-				  buf->direct.buf,
-				  buf->direct.map);
-	else {
-		if (BITS_PER_LONG == 64)
-			vunmap(buf->direct.buf);
+				  buf->direct.buf, buf->direct.map);
+	} else {
+		int i;
 
 		for (i = 0; i < buf->nbufs; ++i)
 			if (buf->page_list[i].buf)
@@ -789,7 +776,7 @@ void mlx4_db_free(struct mlx4_dev *dev, struct mlx4_db *db)
 EXPORT_SYMBOL_GPL(mlx4_db_free);
 
 int mlx4_alloc_hwq_res(struct mlx4_dev *dev, struct mlx4_hwq_resources *wqres,
-		       int size, int max_direct)
+		       int size)
 {
 	int err;
 
@@ -799,7 +786,7 @@ int mlx4_alloc_hwq_res(struct mlx4_dev *dev, struct mlx4_hwq_resources *wqres,
 
 	*wqres->db.db = 0;
 
-	err = mlx4_buf_alloc(dev, size, max_direct, &wqres->buf, GFP_KERNEL);
+	err = mlx4_buf_direct_alloc(dev, size, &wqres->buf, GFP_KERNEL);
 	if (err)
 		goto err_db;
 
diff --git a/drivers/net/ethernet/mellanox/mlx4/en_cq.c b/drivers/net/ethernet/mellanox/mlx4/en_cq.c
index af975a2b74c6..132cea655920 100644
--- a/drivers/net/ethernet/mellanox/mlx4/en_cq.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_cq.c
@@ -73,22 +73,16 @@ int mlx4_en_create_cq(struct mlx4_en_priv *priv,
 	 */
 	set_dev_node(&mdev->dev->persist->pdev->dev, node);
 	err = mlx4_alloc_hwq_res(mdev->dev, &cq->wqres,
-				cq->buf_size, 2 * PAGE_SIZE);
+				cq->buf_size);
 	set_dev_node(&mdev->dev->persist->pdev->dev, mdev->dev->numa_node);
 	if (err)
 		goto err_cq;
 
-	err = mlx4_en_map_buffer(&cq->wqres.buf);
-	if (err)
-		goto err_res;
-
 	cq->buf = (struct mlx4_cqe *)cq->wqres.buf.direct.buf;
 	*pcq = cq;
 
 	return 0;
 
-err_res:
-	mlx4_free_hwq_res(mdev->dev, &cq->wqres, cq->buf_size);
 err_cq:
 	kfree(cq);
 	*pcq = NULL;
@@ -177,7 +171,6 @@ void mlx4_en_destroy_cq(struct mlx4_en_priv *priv, struct mlx4_en_cq **pcq)
 	struct mlx4_en_dev *mdev = priv->mdev;
 	struct mlx4_en_cq *cq = *pcq;
 
-	mlx4_en_unmap_buffer(&cq->wqres.buf);
 	mlx4_free_hwq_res(mdev->dev, &cq->wqres, cq->buf_size);
 	if (mlx4_is_eq_vector_valid(mdev->dev, priv->port, cq->vector) &&
 	    cq->is_tx == RX)
diff --git a/drivers/net/ethernet/mellanox/mlx4/en_netdev.c b/drivers/net/ethernet/mellanox/mlx4/en_netdev.c
index 6f28ac58251c..92e0624f4cf0 100644
--- a/drivers/net/ethernet/mellanox/mlx4/en_netdev.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_netdev.c
@@ -2928,7 +2928,7 @@ int mlx4_en_init_netdev(struct mlx4_en_dev *mdev, int port,
 
 	/* Allocate page for receive rings */
 	err = mlx4_alloc_hwq_res(mdev->dev, &priv->res,
-				MLX4_EN_PAGE_SIZE, MLX4_EN_PAGE_SIZE);
+				MLX4_EN_PAGE_SIZE);
 	if (err) {
 		en_err(priv, "Failed to allocate page for rx qps\n");
 		goto out;
diff --git a/drivers/net/ethernet/mellanox/mlx4/en_resources.c b/drivers/net/ethernet/mellanox/mlx4/en_resources.c
index 02e925d6f734..a6b0db0e0383 100644
--- a/drivers/net/ethernet/mellanox/mlx4/en_resources.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_resources.c
@@ -107,37 +107,6 @@ int mlx4_en_change_mcast_lb(struct mlx4_en_priv *priv, struct mlx4_qp *qp,
 	return ret;
 }
 
-int mlx4_en_map_buffer(struct mlx4_buf *buf)
-{
-	struct page **pages;
-	int i;
-
-	if (BITS_PER_LONG == 64 || buf->nbufs == 1)
-		return 0;
-
-	pages = kmalloc(sizeof *pages * buf->nbufs, GFP_KERNEL);
-	if (!pages)
-		return -ENOMEM;
-
-	for (i = 0; i < buf->nbufs; ++i)
-		pages[i] = virt_to_page(buf->page_list[i].buf);
-
-	buf->direct.buf = vmap(pages, buf->nbufs, VM_MAP, PAGE_KERNEL);
-	kfree(pages);
-	if (!buf->direct.buf)
-		return -ENOMEM;
-
-	return 0;
-}
-
-void mlx4_en_unmap_buffer(struct mlx4_buf *buf)
-{
-	if (BITS_PER_LONG == 64 || buf->nbufs == 1)
-		return;
-
-	vunmap(buf->direct.buf);
-}
-
 void mlx4_en_sqp_event(struct mlx4_qp *qp, enum mlx4_event event)
 {
     return;
diff --git a/drivers/net/ethernet/mellanox/mlx4/en_rx.c b/drivers/net/ethernet/mellanox/mlx4/en_rx.c
index b723e3bcab39..8ef6875b6cf9 100644
--- a/drivers/net/ethernet/mellanox/mlx4/en_rx.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_rx.c
@@ -394,17 +394,11 @@ int mlx4_en_create_rx_ring(struct mlx4_en_priv *priv,
 
 	/* Allocate HW buffers on provided NUMA node */
 	set_dev_node(&mdev->dev->persist->pdev->dev, node);
-	err = mlx4_alloc_hwq_res(mdev->dev, &ring->wqres,
-				 ring->buf_size, 2 * PAGE_SIZE);
+	err = mlx4_alloc_hwq_res(mdev->dev, &ring->wqres, ring->buf_size);
 	set_dev_node(&mdev->dev->persist->pdev->dev, mdev->dev->numa_node);
 	if (err)
 		goto err_info;
 
-	err = mlx4_en_map_buffer(&ring->wqres.buf);
-	if (err) {
-		en_err(priv, "Failed to map RX buffer\n");
-		goto err_hwq;
-	}
 	ring->buf = ring->wqres.buf.direct.buf;
 
 	ring->hwtstamp_rx_filter = priv->hwtstamp_config.rx_filter;
@@ -412,8 +406,6 @@ int mlx4_en_create_rx_ring(struct mlx4_en_priv *priv,
 	*pring = ring;
 	return 0;
 
-err_hwq:
-	mlx4_free_hwq_res(mdev->dev, &ring->wqres, ring->buf_size);
 err_info:
 	vfree(ring->rx_info);
 	ring->rx_info = NULL;
@@ -517,7 +509,6 @@ void mlx4_en_destroy_rx_ring(struct mlx4_en_priv *priv,
 	struct mlx4_en_dev *mdev = priv->mdev;
 	struct mlx4_en_rx_ring *ring = *pring;
 
-	mlx4_en_unmap_buffer(&ring->wqres.buf);
 	mlx4_free_hwq_res(mdev->dev, &ring->wqres, size * stride + TXBB_SIZE);
 	vfree(ring->rx_info);
 	ring->rx_info = NULL;
diff --git a/drivers/net/ethernet/mellanox/mlx4/en_tx.c b/drivers/net/ethernet/mellanox/mlx4/en_tx.c
index 0f206a95429c..f6e61570cb2c 100644
--- a/drivers/net/ethernet/mellanox/mlx4/en_tx.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_tx.c
@@ -94,20 +94,13 @@ int mlx4_en_create_tx_ring(struct mlx4_en_priv *priv,
 
 	/* Allocate HW buffers on provided NUMA node */
 	set_dev_node(&mdev->dev->persist->pdev->dev, node);
-	err = mlx4_alloc_hwq_res(mdev->dev, &ring->wqres, ring->buf_size,
-				 2 * PAGE_SIZE);
+	err = mlx4_alloc_hwq_res(mdev->dev, &ring->wqres, ring->buf_size);
 	set_dev_node(&mdev->dev->persist->pdev->dev, mdev->dev->numa_node);
 	if (err) {
 		en_err(priv, "Failed allocating hwq resources\n");
 		goto err_bounce;
 	}
 
-	err = mlx4_en_map_buffer(&ring->wqres.buf);
-	if (err) {
-		en_err(priv, "Failed to map TX buffer\n");
-		goto err_hwq_res;
-	}
-
 	ring->buf = ring->wqres.buf.direct.buf;
 
 	en_dbg(DRV, priv, "Allocated TX ring (addr:%p) - buf:%p size:%d buf_size:%d dma:%llx\n",
@@ -118,7 +111,7 @@ int mlx4_en_create_tx_ring(struct mlx4_en_priv *priv,
 				    MLX4_RESERVE_ETH_BF_QP);
 	if (err) {
 		en_err(priv, "failed reserving qp for TX ring\n");
-		goto err_map;
+		goto err_hwq_res;
 	}
 
 	err = mlx4_qp_alloc(mdev->dev, ring->qpn, &ring->qp, GFP_KERNEL);
@@ -155,8 +148,6 @@ int mlx4_en_create_tx_ring(struct mlx4_en_priv *priv,
 
 err_reserve:
 	mlx4_qp_release_range(mdev->dev, ring->qpn, 1);
-err_map:
-	mlx4_en_unmap_buffer(&ring->wqres.buf);
 err_hwq_res:
 	mlx4_free_hwq_res(mdev->dev, &ring->wqres, ring->buf_size);
 err_bounce:
@@ -183,7 +174,6 @@ void mlx4_en_destroy_tx_ring(struct mlx4_en_priv *priv,
 	mlx4_qp_remove(mdev->dev, &ring->qp);
 	mlx4_qp_free(mdev->dev, &ring->qp);
 	mlx4_qp_release_range(priv->mdev->dev, ring->qpn, 1);
-	mlx4_en_unmap_buffer(&ring->wqres.buf);
 	mlx4_free_hwq_res(mdev->dev, &ring->wqres, ring->buf_size);
 	kfree(ring->bounce_buf);
 	ring->bounce_buf = NULL;
diff --git a/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h b/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h
index 63b1aeae2c03..cc84e09f324a 100644
--- a/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h
+++ b/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h
@@ -672,8 +672,6 @@ void mlx4_en_fill_qp_context(struct mlx4_en_priv *priv, int size, int stride,
 		int is_tx, int rss, int qpn, int cqn, int user_prio,
 		struct mlx4_qp_context *context);
 void mlx4_en_sqp_event(struct mlx4_qp *qp, enum mlx4_event event);
-int mlx4_en_map_buffer(struct mlx4_buf *buf);
-void mlx4_en_unmap_buffer(struct mlx4_buf *buf);
 int mlx4_en_change_mcast_lb(struct mlx4_en_priv *priv, struct mlx4_qp *qp,
 			    int loopback);
 void mlx4_en_calc_rx_buf(struct net_device *dev);