74edfd483d
Add br_multicast_pg_to_port_ctx() which returns the proper port multicast context from either port or vlan based on bridge option and vlan flags. As the comment inside explains the locking is a bit tricky, we rely on the fact that BR_VLFLAG_MCAST_ENABLED requires multicast_lock to change and we also require it to be held to call that helper. If we find the vlan under rcu and it still has the flag then we can be sure it will be alive until we unlock multicast_lock which should be enough. Note that the context might change from vlan to bridge between different calls to this helper as the mcast vlan knob requires only rtnl so it should be used carefully and for read-only/check purposes. Signed-off-by: Nikolay Aleksandrov <nikolay@nvidia.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.