[PATCH net-next v9 01/14] netdev: add netdev_rx_queue_restart()

Mina Almasry
2024-05-10T23:21:35Z

Add netdev_rx_queue_restart() function to netdev_rx_queue.h

Signed-off-by: David Wei <dw@davidwei.uk>
Signed-off-by: Mina Almasry <almasrymina@google.com>

---

v9: https://lore.kernel.org/all/20240502045410.3524155-4-dw@davidwei.uk/
(submitted by David).
- fixed SPDX license identifier (Simon).
- Rebased on top of merged queue API definition, and changed
implementation to match that.
- Replace rtnl_lock() with rtnl_is_locked() to make it useable from my
netlink code where rtnl is already locked.

---
include/net/netdev_rx_queue.h | 3 ++
net/core/Makefile | 1 +
net/core/netdev_rx_queue.c | 74 +++++++++++++++++++++++++++++++++++
3 files changed, 78 insertions(+)
create mode 100644 net/core/netdev_rx_queue.c

diff --git a/include/net/netdev_rx_queue.h b/include/net/netdev_rx_queue.h
index aa1716fb0e53c..e78ca52d67fbf 100644
--- a/include/net/netdev_rx_queue.h
+++ b/include/net/netdev_rx_queue.h
@@ -54,4 +54,7 @@ get_netdev_rx_queue_index(struct netdev_rx_queue *queue)
return index;
}
#endif
+
+int netdev_rx_queue_restart(struct net_device *dev, unsigned int rxq);
+
#endif
diff --git a/net/core/Makefile b/net/core/Makefile
index 62be9aef25285..f82232b358a2c 100644
--- a/net/core/Makefile
+++ b/net/core/Makefile
@@ -19,6 +19,7 @@ obj-$(CONFIG_NETDEV_ADDR_LIST_TEST) += dev_addr_lists_test.o

obj-y += net-sysfs.o
obj-y += hotdata.o
+obj-y += netdev_rx_queue.o
obj-$(CONFIG_PAGE_POOL) += page_pool.o page_pool_user.o
obj-$(CONFIG_PROC_FS) += net-procfs.o
obj-$(CONFIG_NET_PKTGEN) += pktgen.o
diff --git a/net/core/netdev_rx_queue.c b/net/core/netdev_rx_queue.c
new file mode 100644
index 0000000000000..b3899358e5a9c
--- /dev/null
+++ b/net/core/netdev_rx_queue.c
@@ -0,0 +1,74 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include <linux/netdevice.h>
+#include <net/netdev_queues.h>
+#include <net/netdev_rx_queue.h>
+
+int netdev_rx_queue_restart(struct net_device *dev, unsigned int rxq_idx)
+{
+ void *new_mem, *old_mem;
+ int err;
+
+ if (!dev->queue_mgmt_ops->ndo_queue_stop ||
+ !dev->queue_mgmt_ops->ndo_queue_mem_free ||
+ !dev->queue_mgmt_ops->ndo_queue_mem_alloc ||
+ !dev->queue_mgmt_ops->ndo_queue_start)
+ return -EOPNOTSUPP;
+
+ DEBUG_NET_WARN_ON_ONCE(!rtnl_is_locked());
+
+ new_mem = kvzalloc(dev->queue_mgmt_ops->ndo_queue_mem_size, GFP_KERNEL);
+ if (!new_mem)
+ return -ENOMEM;
+
+ old_mem = kvzalloc(dev->queue_mgmt_ops->ndo_queue_mem_size, GFP_KERNEL);
+ if (!old_mem) {
+ err = -ENOMEM;
+ goto err_free_new_mem;
+ }
+
+ err = dev->queue_mgmt_ops->ndo_queue_mem_alloc(dev, new_mem, rxq_idx);
+ if (err)
+ goto err_free_old_mem;
+
+ err = dev->queue_mgmt_ops->ndo_queue_stop(dev, old_mem, rxq_idx);
+ if (err)
+ goto err_free_new_queue_mem;
+
+ err = dev->queue_mgmt_ops->ndo_queue_start(dev, new_mem, rxq_idx);
+ if (err)
+ goto err_start_queue;
+
+ dev->queue_mgmt_ops->ndo_queue_mem_free(dev, old_mem);
+
+ kvfree(old_mem);
+ kvfree(new_mem);
+
+ return 0;
+
+err_start_queue:
+ /* Restarting the queue with old_mem should be successful as we haven't
+ * changed any of the queue configuration, and there is not much we can
+ * do to recover from a failure here.
+ *
+ * WARN if the we fail to recover the old rx queue, and at least free
+ * old_mem so we don't also leak that.
+ */
+ if (dev->queue_mgmt_ops->ndo_queue_start(dev, old_mem, rxq_idx)) {
+ WARN(1,
+ "Failed to restart old queue in error path. RX queue %d may be unhealthy.",
+ rxq_idx);
+ dev->queue_mgmt_ops->ndo_queue_mem_free(dev, &old_mem);
+ }
+
+err_free_new_queue_mem:
+ dev->queue_mgmt_ops->ndo_queue_mem_free(dev, new_mem);
+
+err_free_old_mem:
+ kvfree(old_mem);
+
+err_free_new_mem:
+ kvfree(new_mem);
+
+ return err;
+}
--
2.45.0.118.g7fe29c98d7-goog