On 03/20, Loktionov, Aleksandr wrote:
quoted
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From: Intel-wired-lan <redacted> On Behalf
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Subject: [Intel-wired-lan] [PATCH net-next v3 03/13] net: introduce
ndo_set_rx_mode_async and dev_rx_mode_work
Add ndo_set_rx_mode_async callback that drivers can implement instead
of the legacy ndo_set_rx_mode. The legacy callback runs under the
netif_addr_lock spinlock with BHs disabled, preventing drivers from
sleeping. The async variant runs from a work queue with rtnl_lock and
netdev_lock_ops held, in fully sleepable context.
When __dev_set_rx_mode() sees ndo_set_rx_mode_async, it schedules
dev_rx_mode_work instead of calling the driver inline. The work
function takes two snapshots of each address list (uc/mc) under the
addr_lock, then drops the lock and calls the driver with the work
copies. After the driver returns, it reconciles the snapshots back to
the real lists under the lock.
Reviewed-by: Aleksandr Loktionov <redacted>
Signed-off-by: Stanislav Fomichev <sdf@fomichev.me>
---
Documentation/networking/netdevices.rst | 8 +++
include/linux/netdevice.h | 20 ++++++
net/core/dev.c | 95 +++++++++++++++++++++++-
-
3 files changed, 116 insertions(+), 7 deletions(-)
diff --git a/Documentation/networking/netdevices.rst
b/Documentation/networking/netdevices.rst
index 35704d115312..dc83d78d3b27 100644
--- a/Documentation/networking/netdevices.rst
+++ b/Documentation/networking/netdevices.rst
@@ -289,6 +289,14 @@ struct net_device synchronization rules
ndo_set_rx_mode:
Synchronization: netif_addr_lock spinlock.
Context: BHs disabled
...
quoted
to
+device
+ * and configure RX filtering.
+ * @dev: device
+ *
+ * When the device doesn't support unicast filtering it is put in
+promiscuous
+ * mode while unicast addresses are present.
*/
void __dev_set_rx_mode(struct net_device *dev) {
const struct net_device_ops *ops = dev->netdev_ops;
/* dev_open will call this function so the list will stay sane.
*/
- if (!(dev->flags&IFF_UP))
+ if (!netif_up_and_present(dev))
return;
- if (!netif_device_present(dev))
+ if (ops->ndo_set_rx_mode_async) {
+ queue_work(rx_mode_wq, &dev->rx_mode_work);
return;
This early return skips the legacy core fallback below.
Before this patch, __dev_set_rx_mode() continued into the
existing unicast-filter handling when the device did not
advertise IFF_UNICAST_FLT.
After this patch, any driver that implements
ndo_set_rx_mode_async but does not set IFF_UNICAST_FLT
will never hit that fallback path.
I believe this is addressed later in "net: move promiscuity handling into
dev_rx_mode_work"? That should take care of doing __dev_set_promiscuity
for !IFF_UNICAST_FLT+ndo_set_rx_mode_async. Not sure if there is a
better way to rearrange the chunks in the patches.
if (ops->ndo_set_rx_mode_async) {
...
+ promisc_inc = dev_uc_promisc_update(dev);
+
+ netif_addr_unlock_bh(dev);
+ } else {
+ netif_addr_lock_bh(dev);
+ promisc_inc = dev_uc_promisc_update(dev);
+ netif_addr_unlock_bh(dev);
+ }
+
+ if (promisc_inc)
+ __dev_set_promiscuity(dev, promisc_inc, false);
+