netdev_queue_get_dma_dev() uses "compat" locking assert which wants
either the rtnl_lock or netdev instance lock. This is not right,
the callers are taking the instance lock unconditionally. All entry
points for queue config are purely instance locked.
In other words the callers use netdev_get_by_index_lock(), not
netdev_get_by_index_lock_ops_compat(). All the state we will
access is effectively instance lock protected (it's const for
devices which are not ops-locked).
Update the assert to avoid false positive warnings.
Cc: [email protected]
Fixes: b6c5f9454e ("io_uring/zcrx: call netdev_queue_get_dma_dev() under instance lock")
Reported-by: [email protected]
Reviewed-by: Simon Horman <[email protected]>
Acked-by: Daniel Borkmann <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>
Jakub suggests renaming the existing assert to match
the netdev_lock_ops_compat() semantics.
We want netdev_assert_locked_ops() to mean - if the driver
is ops locked - check that it's holding the device lock.
The existing helper check for either ops lock or rtnl_lock,
which is the locking behavior of netdev_lock_ops_compat().
The reason for naming divergence is likely that
netdev_ops_assert_locked() predated the _compat() helpers.
Suggested-by: Jakub Sitnicki <[email protected]>
Reviewed-by: Nicolai Buchwitz <[email protected]>
Reviewed-by: Jakub Sitnicki <[email protected]>
Acked-by: Stanislav Fomichev <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>
The netif_get_rx_queue_lease_locked() API hides the locking
and the descend onto the leased queue. Making the code
harder to follow (at least to me). Remove the API and open
code the descend a bit. Most of the code now looks like:
if (!leased)
return __helper(x);
hw_rxq = ..
netdev_lock(hw_rxq->dev);
ret = __helper(x);
netdev_unlock(hw_rxq->dev);
return ret;
Of course if we have more code paths that need the wrapping
we may need to revisit. For now, IMHO, having to know what
netif_get_rx_queue_lease_locked() does is not worth the 20LoC
it saves.
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>
Extend netdev_queue_get_dma_dev to return the physical device of the
real rxq for DMA in case the queue was leased. This allows memory
providers like io_uring zero-copy or devmem to bind to the physically
leased rxq via virtual devices such as netkit.
Signed-off-by: David Wei <[email protected]>
Co-developed-by: Daniel Borkmann <[email protected]>
Signed-off-by: Daniel Borkmann <[email protected]>
Reviewed-by: Nikolay Aleksandrov <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>
Implement netdev_nl_queue_create_doit which creates a new rx queue in a
virtual netdev and then leases it to a rx queue in a physical netdev.
Example with ynl client:
# ynl --family netdev --output-json --do queue-create \
--json '{"ifindex": 8, "type": "rx", "lease": {"ifindex": 4, "queue": {"type": "rx", "id": 15}}}'
{'id': 1}
Note that the netdevice locking order is always from the virtual to
the physical device.
Signed-off-by: Daniel Borkmann <[email protected]>
Co-developed-by: David Wei <[email protected]>
Signed-off-by: David Wei <[email protected]>
Reviewed-by: Nikolay Aleksandrov <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>
For zerocopy (io_uring, devmem), there is an assumption that the
parent device can do DMA. However that is not always the case:
- Scalable Function netdevs [1] have the DMA device in the grandparent.
- For Multi-PF netdevs [2] queues can be associated to different DMA
devices.
This patch introduces the a queue based interface for allowing drivers
to expose a different DMA device for zerocopy.
[1] Documentation/networking/device_drivers/ethernet/mellanox/mlx5/switchdev.rst
[2] Documentation/networking/multi-pf-netdev.rst
Signed-off-by: Dragos Tatulea <[email protected]>
Reviewed-by: Pavel Begunkov <[email protected]>
Reviewed-by: Mina Almasry <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>
Jakub Kicinski