devlink: introduce a helper for netlink multicast send

Introduce a helper devlink_nl_notify_send() so each object notification
function does not have to call genlmsg_multicast_netns() with the same
arguments.

Signed-off-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

devlink: send notifications only if there are listeners

Introduce devlink_nl_notify_need() helper and using it to check at the
beginning of notification functions to avoid overhead of composing
notification messages in case nobody listens.

Signed-off-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

devlink: introduce __devl_is_registered() helper and use it instead of xa_get_mark()

Introduce __devl_is_registered() which does not assert on devlink
instance lock and use it in notifications which may be called
without devlink instance lock held.

Signed-off-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

devlink: Allow taking device lock in pre_doit operations

Introduce a new private flag ('DEVLINK_NL_FLAG_NEED_DEV_LOCK') to allow
netlink commands to specify that they need to acquire the device lock in
their pre_doit operation and release it in their post_doit operation.

The reload command will use this flag in the subsequent patch.

No functional changes intended.

Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: Petr Machata <petrm@nvidia.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

devlink: rename netlink callback to be aligned with the generated ones

All remaining doit and dumpit netlink callback functions are going to be
used by generated split ops. They expect certain name format. Rename the
callback to be aligned with generated names.

Signed-off-by: Jiri Pirko <jiri@nvidia.com>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Link: https://lore.kernel.org/r/20231021112711.660606-8-jiri@resnulli.us
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

devlink: push region related code into separate file

Cut out another chunk from leftover.c and put region related code
into a separate file.

Signed-off-by: Jiri Pirko <jiri@nvidia.com>
Link: https://lore.kernel.org/r/20230828061657.300667-9-jiri@resnulli.us
Signed-off-by: Jakub Kicinski <kuba@kernel.org>