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Message-ID: <20240502045410.3524155-4-dw@davidwei.uk>
Date: Wed, 1 May 2024 21:54:04 -0700
From: David Wei <dw@...idwei.uk>
To: netdev@...r.kernel.org,
Michael Chan <michael.chan@...adcom.com>,
Pavan Chebbi <pavan.chebbi@...adcom.com>,
Andy Gospodarek <andrew.gospodarek@...adcom.com>,
Adrian Alvarado <adrian.alvarado@...adcom.com>,
Mina Almasry <almasrymina@...gle.com>,
Shailend Chand <shailend@...gle.com>
Cc: Jakub Kicinski <kuba@...nel.org>,
"David S. Miller" <davem@...emloft.net>,
Eric Dumazet <edumazet@...gle.com>,
Paolo Abeni <pabeni@...hat.com>
Subject: [RFC PATCH net-next v2 3/9] netdev: add netdev_rx_queue_restart()
From: Mina Almasry <almasrymina@...gle.com>
Add netdev_rx_queue_restart() function to netdev_rx_queue.h. This is
taken from Mina's work in [1] with a slight modification of taking
rtnl_lock() during the queue stop and start ops.
For bnxt specifically, if the firmware doesn't support
BNXT_RST_RING_SP_EVENT, then ndo_queue_stop() returns -EOPNOTSUPP and
the whole restart fails. Unlike bnxt_rx_ring_reset(), there is no
attempt to reset the whole device.
[1]: https://lore.kernel.org/linux-kernel/20240403002053.2376017-6-almasrymina@google.com/#t
Signed-off-by: David Wei <dw@...idwei.uk>
---
include/net/netdev_rx_queue.h | 3 ++
net/core/Makefile | 1 +
net/core/netdev_rx_queue.c | 58 +++++++++++++++++++++++++++++++++++
3 files changed, 62 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 aa1716fb0e53..e78ca52d67fb 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 21d6fbc7e884..f2aa63c167a3 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 000000000000..9633fb36f6d1
--- /dev/null
+++ b/net/core/netdev_rx_queue.c
@@ -0,0 +1,58 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#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)
+{
+ void *new_mem;
+ void *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;
+
+ new_mem = dev->queue_mgmt_ops->ndo_queue_mem_alloc(dev, rxq);
+ if (!new_mem)
+ return -ENOMEM;
+
+ rtnl_lock();
+ err = dev->queue_mgmt_ops->ndo_queue_stop(dev, rxq, &old_mem);
+ if (err)
+ goto err_free_new_mem;
+
+ err = dev->queue_mgmt_ops->ndo_queue_start(dev, rxq, new_mem);
+ if (err)
+ goto err_start_queue;
+ rtnl_unlock();
+
+ dev->queue_mgmt_ops->ndo_queue_mem_free(dev, old_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, rxq, old_mem)) {
+ WARN(1,
+ "Failed to restart old queue in error path. RX queue %d may be unhealthy.",
+ rxq);
+ dev->queue_mgmt_ops->ndo_queue_mem_free(dev, &old_mem);
+ }
+
+err_free_new_mem:
+ dev->queue_mgmt_ops->ndo_queue_mem_free(dev, new_mem);
+ rtnl_unlock();
+
+ return err;
+}
+EXPORT_SYMBOL_GPL(netdev_rx_queue_restart);
--
2.43.0
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