linux-stable.git/include/linux/netpoll.h, branch v6.12.91

netconsole: allow selection of egress interface via MAC address

2026-05-23T11:04:54+00:00

[ Upstream commit f8a10bed32f5fbede13a5f22fdc4ab8740ea213a ]

Currently, netconsole has two methods of configuration - module
parameter and configfs. The former interface allows for netconsole
activation earlier during boot (by specifying the module parameter on
the kernel command line), so it is preferred for debugging issues which
arise before userspace is up/the configfs interface can be used. The
module parameter syntax requires specifying the egress interface name.
This requirement makes it hard to use for a couple reasons:
- The egress interface name can be hard or impossible to predict. For
  example, installing a new network card in a system can change the
  interface names assigned by the kernel.
- When constructing the module parameter, one may have trouble
  determining the original (kernel-assigned) name of the interface
  (which is the name that should be given to netconsole) if some stable
  interface naming scheme is in effect. A human can usually look at
  kernel logs to determine the original name, but this is very painful
  if automation is constructing the parameter.

For these reasons, allow selection of the egress interface via MAC
address when configuring netconsole using the module parameter. Update
the netconsole documentation with an example of the new syntax.
Selection of egress interface by MAC address via configfs is far less
interesting (since when this interface can be used, one should be able
to easily convert between MAC address and interface name), so it is left
unimplemented.

Signed-off-by: Uday Shankar 
Reviewed-by: Breno Leitao 
Tested-by: Breno Leitao 
Reviewed-by: Simon Horman 
Link: https://patch.msgid.link/20250312-netconsole-v6-2-3437933e79b8@purestorage.com
Signed-off-by: Paolo Abeni 
Stable-dep-of: 3bc179bc7146 ("netpoll: fix IPv6 local-address corruption")
Signed-off-by: Sasha Levin

net: netpoll: Individualize the skb pool

2025-11-24T09:36:06+00:00

[ Upstream commit 221a9c1df790fa711d65daf5ba05d0addc279153 ]

The current implementation of the netpoll system uses a global skb
pool, which can lead to inefficient memory usage and
waste when targets are disabled or no longer in use.

This can result in a significant amount of memory being unnecessarily
allocated and retained, potentially causing performance issues and
limiting the availability of resources for other system components.

Modify the netpoll system to assign a skb pool to each target instead of
using a global one.

This approach allows for more fine-grained control over memory
allocation and deallocation, ensuring that resources are only allocated
and retained as needed.

Signed-off-by: Breno Leitao 
Link: https://patch.msgid.link/20241114-skb_buffers_v2-v3-1-9be9f52a8b69@debian.org
Signed-off-by: Jakub Kicinski 
Stable-dep-of: 49c8d2c1f94c ("net: netpoll: fix incorrect refcount handling causing incorrect cleanup")
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

netpoll: Use rcu_access_pointer() in netpoll_poll_lock

2024-12-05T13:02:01+00:00

[ Upstream commit a57d5a72f8dec7db8a79d0016fb0a3bdecc82b56 ]

The ndev->npinfo pointer in netpoll_poll_lock() is RCU-protected but is
being accessed directly for a NULL check. While no RCU read lock is held
in this context, we should still use proper RCU primitives for
consistency and correctness.

Replace the direct NULL check with rcu_access_pointer(), which is the
appropriate primitive when only checking for NULL without dereferencing
the pointer. This function provides the necessary ordering guarantees
without requiring RCU read-side protection.

Fixes: bea3348eef27 ("[NET]: Make NAPI polling independent of struct net_device objects.")
Signed-off-by: Breno Leitao 
Reviewed-by: Michal Kubiak 
Link: https://patch.msgid.link/20241118-netpoll_rcu-v1-2-a1888dcb4a02@debian.org
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin

net: netpoll: extract core of netpoll_cleanup

2024-08-13T08:58:58+00:00

Extract the core part of netpoll_cleanup(), so, it could be called from
a caller that has the rtnl lock already.

Netconsole uses this in a weird way right now:

	__netpoll_cleanup(&nt->np);
	spin_lock_irqsave(&target_list_lock, flags);
	netdev_put(nt->np.dev, &nt->np.dev_tracker);
	nt->np.dev = NULL;
	nt->enabled = false;

This will be replaced by do_netpoll_cleanup() as the locking situation
is overhauled.

Signed-off-by: Breno Leitao 
Reviewed-by: Rik van Riel 
Signed-off-by: Paolo Abeni

netpoll: add net device refcount tracker to struct netpoll

2021-12-07T00:06:02+00:00

Signed-off-by: Eric Dumazet 
Signed-off-by: Jakub Kicinski

netpoll: Remove unused inline function netpoll_netdev_init()

2020-07-15T14:45:25+00:00

commit d565b0a1a9b6 ("net: Add Generic Receive Offload infrastructure")
left behind this, remove it.

Signed-off-by: YueHaibing 
Signed-off-by: David S. Miller

netpoll: netpoll_send_skb() returns transmit status

2020-05-08T01:11:07+00:00

Some callers want to know if the packet has been sent or
dropped, to inform upper stacks.

Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller

netpoll: move netpoll_send_skb() out of line

2020-05-08T01:11:07+00:00

There is no need to inline this helper, as we intend to add more
code in this function.

Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller

netpoll: remove dev argument from netpoll_send_skb_on_dev()

2020-05-08T01:11:07+00:00

netpoll_send_skb_on_dev() can get the device pointer directly from np->dev

Rename it to __netpoll_send_skb()

Following patch will move netpoll_send_skb() out-of-line.

Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller

netpoll: allow cleanup to be synchronous

2018-10-20T00:01:43+00:00

This fixes a problem introduced by:
commit 2cde6acd49da ("netpoll: Fix __netpoll_rcu_free so that it can hold the rtnl lock")

When using netconsole on a bond, __netpoll_cleanup can asynchronously
recurse multiple times, each __netpoll_free_async call can result in
more __netpoll_free_async's. This means there is now a race between
cleanup_work queues on multiple netpoll_info's on multiple devices and
the configuration of a new netpoll. For example if a netconsole is set
to enable 0, reconfigured, and enable 1 immediately, this netconsole
will likely not work.

Given the reason for __netpoll_free_async is it can be called when rtnl
is not locked, if it is locked, we should be able to execute
synchronously. It appears to be locked everywhere it's called from.

Generalize the design pattern from the teaming driver for current
callers of __netpoll_free_async.

CC: Neil Horman 
CC: "David S. Miller" 
Signed-off-by: Debabrata Banerjee 
Signed-off-by: David S. Miller