Vladimir Oltean d78637a8a0 net: dsa: felix: remove dead code in felix_setup_mmio_filtering()
There has been some controversy related to the sanity check that a CPU
port exists, and commit e8b1d76980 ("net: dsa: felix: Fix memory leak
in felix_setup_mmio_filtering") even "corrected" an apparent memory leak
as static analysis tools see it.

However, the check is completely dead code, since the earliest point at
which felix_setup_mmio_filtering() can be called is:

felix_pci_probe
-> dsa_register_switch
   -> dsa_switch_probe
      -> dsa_tree_setup
         -> dsa_tree_setup_cpu_ports
            -> dsa_tree_setup_default_cpu
               -> contains the "DSA: tree %d has no CPU port\n" check
         -> dsa_tree_setup_master
            -> dsa_master_setup
               -> sysfs_create_group(&dev->dev.kobj, &dsa_group);
                  -> makes tagging_store() callable
                     -> dsa_tree_change_tag_proto
                        -> dsa_tree_notify
                           -> dsa_switch_event
                              -> dsa_switch_change_tag_proto
                                 -> ds->ops->change_tag_protocol
                                    -> felix_change_tag_protocol
                                       -> felix_set_tag_protocol
                                          -> felix_setup_tag_8021q
                                             -> felix_setup_mmio_filtering
                                                -> breaks at first CPU port

So probing would have failed earlier if there wasn't any CPU port
defined.

To avoid all confusion, delete the dead code and replace it with a
comment.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2022-02-17 14:06:51 +00:00
2022-02-06 12:20:50 -08:00
…

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.
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