[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <20260121073517.3323332-2-kiran.kella@broadcom.com>
Date: Tue, 20 Jan 2026 23:35:16 -0800
From: Kiran Kella <kiran.kella@...adcom.com>
To: davem@...emloft.net,
edumazet@...gle.com,
kuba@...nel.org,
pabeni@...hat.com,
andrew+netdev@...n.ch,
horms@...nel.org
Cc: netdev@...r.kernel.org,
linux-kernel@...r.kernel.org,
jayakrishnan.udayavarma@...adcom.com,
ajit.khaparde@...adcom.com,
akhilesh.samineni@...adcom.com,
Kiran Kella <kiran.kella@...adcom.com>
Subject: [net-next 1/2] psp: Support for transmit on logical device when the underlying transport device supports PSP.
This is achieved by propagating the psp_dev from the lower device
to the upper devices in the device stack via a netdevice notifier.
The lowest device owns the psp_dev pointer while the upper devices
just borrow the pointer. When the lower device is unlinked, the
borrowed pointer is cleared in the upper device.
Assumption being that psp_dev is set on the lowest device before
any upper devices stack are linked on that lowest device at a
later point of time.
In case of bond devices:
- If an upper device has multiple lower devices, the psp_dev is
not propogated as it would be ambiguous which slave will be used
for transmission.
- If a bond device transitions from having one slave device to
multiple slaves, any previously borrowed psp_dev pointer is
cleared to avoid ambiguity.
Signed-off-by: Kiran Kella <kiran.kella@...adcom.com>
Reviewed-by: Ajit Kumar Khaparde <ajit.khaparde@...adcom.com>
Reviewed-by: Akhilesh Samineni <akhilesh.samineni@...adcom.com>
---
net/psp/psp_main.c | 114 +++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 114 insertions(+)
diff --git a/net/psp/psp_main.c b/net/psp/psp_main.c
index a8534124f626..0bff50c9314d 100644
--- a/net/psp/psp_main.c
+++ b/net/psp/psp_main.c
@@ -313,10 +313,124 @@ int psp_dev_rcv(struct sk_buff *skb, u16 dev_id, u8 generation, bool strip_icv)
}
EXPORT_SYMBOL(psp_dev_rcv);
+/**
+ * psp_netdevice_event() - Handle netdevice events for PSP device propagation
+ * @nb: notifier block
+ * @event: netdevice event
+ * @ptr: netdevice notifier info
+ *
+ * Propagates psp_dev pointer from lower devices to upper devices when
+ * upper devices are created (e.g., VLAN subinterfaces).
+ */
+static int psp_netdevice_event(struct notifier_block *nb,
+ unsigned long event, void *ptr)
+{
+ struct netdev_notifier_changeupper_info *info;
+ struct net_device *dev, *upper_dev;
+ struct psp_dev *psd;
+
+ if (event != NETDEV_CHANGEUPPER)
+ return NOTIFY_DONE;
+
+ info = ptr;
+ dev = netdev_notifier_info_to_dev(ptr);
+ upper_dev = info->upper_dev;
+
+ if (info->linking) {
+ bool has_multiple_lowers = false;
+ struct list_head *iter;
+
+ /* Lower device is being linked to an upper device.
+ * Propagate psp_dev from the immediate lower device to the
+ * upper device. The immediate lower device would have already
+ * got the psp_dev pointer set in a previous notification (or
+ * owns it if it's the lowest device),
+ * Upper devices just borrow the pointer.
+ *
+ * However, if the upper device has multiple lower devices,
+ * don't propagate psp_dev as it would be ambiguous
+ * which slave will be used for transmission (eg., bond device).
+ * If the upper device already has psp_dev set and is getting
+ * a second lower device, clear the psp_dev.
+ */
+
+ rcu_read_lock();
+ iter = &upper_dev->adj_list.lower;
+ /* Check if there's a second lower device */
+ if (netdev_next_lower_dev_rcu(upper_dev, &iter))
+ if (netdev_next_lower_dev_rcu(upper_dev, &iter))
+ has_multiple_lowers = true;
+
+ /* If upper device now has multiple lower devices, clear psp_dev
+ * if it was previously set (from when it had only one slave).
+ */
+ if (has_multiple_lowers) {
+ psd = rcu_dereference(upper_dev->psp_dev);
+ rcu_read_unlock();
+ if (psd)
+ rcu_assign_pointer(upper_dev->psp_dev, NULL);
+
+ return NOTIFY_DONE;
+ }
+
+ /* Get psp_dev from the immediate lower device */
+ psd = rcu_dereference(dev->psp_dev);
+ rcu_read_unlock();
+
+ /* Propagate psp_dev to upper device if found */
+ if (psd)
+ rcu_assign_pointer(upper_dev->psp_dev, psd);
+ } else {
+ struct net_device *remaining_lower = NULL;
+ bool has_single_lower = false;
+ struct list_head *iter;
+
+ /* Lower device is being unlinked from an upper device.
+ * After unlinking, check if the upper device now has exactly
+ * one lower device remaining. If so, propagate psp_dev from
+ * that remaining lower device to the upper device.
+ */
+
+ rcu_read_lock();
+ iter = &upper_dev->adj_list.lower;
+ remaining_lower = netdev_next_lower_dev_rcu(upper_dev, &iter);
+ /* Check if there's a second lower device */
+ if (remaining_lower)
+ if (!netdev_next_lower_dev_rcu(upper_dev, &iter))
+ has_single_lower = true;
+
+ if (has_single_lower) {
+ /* Upper device now has exactly one lower device.
+ * Propagate psp_dev from the remaining lower device.
+ */
+ psd = rcu_dereference(remaining_lower->psp_dev);
+ rcu_read_unlock();
+ if (psd)
+ rcu_assign_pointer(upper_dev->psp_dev, psd);
+ } else {
+ /* Upper device has zero or multiple lower devices.
+ * Clear psp_dev if it was previously set.
+ */
+ psd = rcu_dereference(upper_dev->psp_dev);
+ rcu_read_unlock();
+ if (psd)
+ rcu_assign_pointer(upper_dev->psp_dev, NULL);
+ }
+ }
+
+ return NOTIFY_DONE;
+}
+
+static struct notifier_block psp_netdevice_notifier = {
+ .notifier_call = psp_netdevice_event,
+};
+
static int __init psp_init(void)
{
mutex_init(&psp_devs_lock);
+ register_netdevice_notifier(&psp_netdevice_notifier);
+
return genl_register_family(&psp_nl_family);
}
--
2.45.4
Powered by blists - more mailing lists