1 files changed, 53 insertions, 22 deletions

diff --git a/drivers/ntb/ntb_transport.c b/drivers/ntb/ntb_transport.c
index e6d1f5b298f3..eb875e3db2e3 100644
--- a/drivers/ntb/ntb_transport.c
+++ b/drivers/ntb/ntb_transport.c
@@ -59,6 +59,7 @@
 #include <linux/slab.h>
 #include <linux/types.h>
 #include <linux/uaccess.h>
+#include <linux/mutex.h>
 #include "linux/ntb.h"
 #include "linux/ntb_transport.h"
 
@@ -241,6 +242,9 @@ struct ntb_transport_ctx {
 	struct work_struct link_cleanup;
 
 	struct dentry *debugfs_node_dir;
+
+	/* Make sure workq of link event be executed serially */
+	struct mutex link_event_lock;
 };
 
 enum {
@@ -284,7 +288,7 @@ static void ntb_memcpy_rx(struct ntb_queue_entry *entry, void *offset);
 
 
 static int ntb_transport_bus_match(struct device *dev,
-				   struct device_driver *drv)
+				   const struct device_driver *drv)
 {
 	return !strncmp(dev_name(dev), drv->name, strlen(drv->name));
 }
@@ -304,7 +308,7 @@ static int ntb_transport_bus_probe(struct device *dev)
 	return rc;
 }
 
-static int ntb_transport_bus_remove(struct device *dev)
+static void ntb_transport_bus_remove(struct device *dev)
 {
 	const struct ntb_transport_client *client;
 
@@ -312,11 +316,9 @@ static int ntb_transport_bus_remove(struct device *dev)
 	client->remove(dev);
 
 	put_device(dev);
-
-	return 0;
 }
 
-static struct bus_type ntb_transport_bus = {
+static const struct bus_type ntb_transport_bus = {
 	.name = "ntb_transport",
 	.match = ntb_transport_bus_match,
 	.probe = ntb_transport_bus_probe,
@@ -379,6 +381,8 @@ EXPORT_SYMBOL_GPL(ntb_transport_unregister_client_dev);
  * @device_name: Name of NTB client device
  *
  * Register an NTB client device with the NTB transport layer
+ *
+ * Returns: %0 on success or -errno code on error
  */
 int ntb_transport_register_client_dev(char *device_name)
 {
@@ -412,7 +416,7 @@ int ntb_transport_register_client_dev(char *device_name)
 
 		rc = device_register(dev);
 		if (rc) {
-			kfree(client_dev);
+			put_device(dev);
 			goto err;
 		}
 
@@ -809,16 +813,29 @@ static void ntb_free_mw(struct ntb_transport_ctx *nt, int num_mw)
 }
 
 static int ntb_alloc_mw_buffer(struct ntb_transport_mw *mw,
-			       struct device *dma_dev, size_t align)
+			       struct device *ntb_dev, size_t align)
 {
 	dma_addr_t dma_addr;
 	void *alloc_addr, *virt_addr;
 	int rc;
 
-	alloc_addr = dma_alloc_coherent(dma_dev, mw->alloc_size,
-					&dma_addr, GFP_KERNEL);
+	/*
+	 * The buffer here is allocated against the NTB device. The reason to
+	 * use dma_alloc_*() call is to allocate a large IOVA contiguous buffer
+	 * backing the NTB BAR for the remote host to write to. During receive
+	 * processing, the data is being copied out of the receive buffer to
+	 * the kernel skbuff. When a DMA device is being used, dma_map_page()
+	 * is called on the kvaddr of the receive buffer (from dma_alloc_*())
+	 * and remapped against the DMA device. It appears to be a double
+	 * DMA mapping of buffers, but first is mapped to the NTB device and
+	 * second is to the DMA device. DMA_ATTR_FORCE_CONTIGUOUS is necessary
+	 * in order for the later dma_map_page() to not fail.
+	 */
+	alloc_addr = dma_alloc_attrs(ntb_dev, mw->alloc_size,
+				     &dma_addr, GFP_KERNEL,
+				     DMA_ATTR_FORCE_CONTIGUOUS);
 	if (!alloc_addr) {
-		dev_err(dma_dev, "Unable to alloc MW buff of size %zu\n",
+		dev_err(ntb_dev, "Unable to alloc MW buff of size %zu\n",
 			mw->alloc_size);
 		return -ENOMEM;
 	}
@@ -847,7 +864,7 @@ static int ntb_alloc_mw_buffer(struct ntb_transport_mw *mw,
 	return 0;
 
 err:
-	dma_free_coherent(dma_dev, mw->alloc_size, alloc_addr, dma_addr);
+	dma_free_coherent(ntb_dev, mw->alloc_size, alloc_addr, dma_addr);
 
 	return rc;
 }
@@ -911,7 +928,7 @@ static int ntb_set_mw(struct ntb_transport_ctx *nt, int num_mw,
 	return 0;
 }
 
-static void ntb_qp_link_down_reset(struct ntb_transport_qp *qp)
+static void ntb_qp_link_context_reset(struct ntb_transport_qp *qp)
 {
 	qp->link_is_up = false;
 	qp->active = false;
@@ -934,6 +951,13 @@ static void ntb_qp_link_down_reset(struct ntb_transport_qp *qp)
 	qp->tx_async = 0;
 }
 
+static void ntb_qp_link_down_reset(struct ntb_transport_qp *qp)
+{
+	ntb_qp_link_context_reset(qp);
+	if (qp->remote_rx_info)
+		qp->remote_rx_info->entry = qp->rx_max_entry - 1;
+}
+
 static void ntb_qp_link_cleanup(struct ntb_transport_qp *qp)
 {
 	struct ntb_transport_ctx *nt = qp->transport;
@@ -1004,6 +1028,7 @@ static void ntb_transport_link_cleanup_work(struct work_struct *work)
 	struct ntb_transport_ctx *nt =
 		container_of(work, struct ntb_transport_ctx, link_cleanup);
 
+	guard(mutex)(&nt->link_event_lock);
 	ntb_transport_link_cleanup(nt);
 }
 
@@ -1027,6 +1052,8 @@ static void ntb_transport_link_work(struct work_struct *work)
 	u32 val;
 	int rc = 0, i, spad;
 
+	guard(mutex)(&nt->link_event_lock);
+
 	/* send the local info, in the opposite order of the way we read it */
 
 	if (nt->use_msi) {
@@ -1176,7 +1203,7 @@ static int ntb_transport_init_queue(struct ntb_transport_ctx *nt,
 	qp->ndev = nt->ndev;
 	qp->client_ready = false;
 	qp->event_handler = NULL;
-	ntb_qp_link_down_reset(qp);
+	ntb_qp_link_context_reset(qp);
 
 	if (mw_num < qp_count % mw_count)
 		num_qps_mw = qp_count / mw_count + 1;
@@ -1333,7 +1360,7 @@ static int ntb_transport_probe(struct ntb_client *self, struct ntb_dev *ndev)
 	qp_count = ilog2(qp_bitmap);
 	if (nt->use_msi) {
 		qp_count -= 1;
-		nt->msi_db_mask = 1 << qp_count;
+		nt->msi_db_mask = BIT_ULL(qp_count);
 		ntb_db_clear_mask(ndev, nt->msi_db_mask);
 	}
 
@@ -1483,7 +1510,7 @@ static void ntb_rx_copy_callback(void *data,
 		case DMA_TRANS_READ_FAILED:
 		case DMA_TRANS_WRITE_FAILED:
 			entry->errors++;
-			/* fall through */
+			fallthrough;
 		case DMA_TRANS_ABORTED:
 		{
 			struct ntb_transport_qp *qp = entry->qp;
@@ -1739,7 +1766,7 @@ static void ntb_tx_copy_callback(void *data,
 		case DMA_TRANS_READ_FAILED:
 		case DMA_TRANS_WRITE_FAILED:
 			entry->errors++;
-			/* fall through */
+			fallthrough;
 		case DMA_TRANS_ABORTED:
 		{
 			void __iomem *offset =
@@ -1896,7 +1923,7 @@ err:
 static int ntb_process_tx(struct ntb_transport_qp *qp,
 			  struct ntb_queue_entry *entry)
 {
-	if (qp->tx_index == qp->remote_rx_info->entry) {
+	if (!ntb_transport_tx_free_entry(qp)) {
 		qp->tx_ring_full++;
 		return -EAGAIN;
 	}
@@ -1961,9 +1988,9 @@ static bool ntb_dma_filter_fn(struct dma_chan *chan, void *node)
 
 /**
  * ntb_transport_create_queue - Create a new NTB transport layer queue
- * @rx_handler: receive callback function
- * @tx_handler: transmit callback function
- * @event_handler: event callback function
+ * @data: pointer for callback data
+ * @client_dev: &struct device pointer
+ * @handlers: pointer to various ntb queue (callback) handlers
  *
  * Create a new NTB transport layer queue and provide the queue with a callback
  * routine for both transmit and receive.  The receive callback routine will be
@@ -2278,9 +2305,13 @@ int ntb_transport_tx_enqueue(struct ntb_transport_qp *qp, void *cb, void *data,
 	struct ntb_queue_entry *entry;
 	int rc;
 
-	if (!qp || !qp->link_is_up || !len)
+	if (!qp || !len)
 		return -EINVAL;
 
+	/* If the qp link is down already, just ignore. */
+	if (!qp->link_is_up)
+		return 0;
+
 	entry = ntb_list_rm(&qp->ntb_tx_free_q_lock, &qp->tx_free_q);
 	if (!entry) {
 		qp->tx_err_no_buf++;
@@ -2420,7 +2451,7 @@ unsigned int ntb_transport_tx_free_entry(struct ntb_transport_qp *qp)
 	unsigned int head = qp->tx_index;
 	unsigned int tail = qp->remote_rx_info->entry;
 
-	return tail > head ? tail - head : qp->tx_max_entry + tail - head;
+	return tail >= head ? tail - head : qp->tx_max_entry + tail - head;
 }
 EXPORT_SYMBOL_GPL(ntb_transport_tx_free_entry);