Request for backport 4.19 for the IPMI driver

[Corey Minyard <minyard@acm.org>]

Please backport the following changes to the 4.18 stable kernel:

  e1891cffd4c4 "ipmi: Make the smi watcher be disabled immediately when not needed"
  383035211c79 "ipmi: move message error checking to avoid deadlock"

e1891cffd4c4 doesn't apply completely cleanly because of other changes,
but you just need to leave in the free_user_work() function and delete
the other function in the conflict.  I can also supply a patch if
necessary.

Change

  b4a34aa6d "ipmi: Fix how the lower layers are told to watch for messages"

was backported to fullfill a dependency for another backport, but there
was another change:

  e1891cffd4c4 "ipmi: Make the smi watcher be disabled immediately when not needed"

That is needed to avoid calling a lower layer function with
xmit_msgs_lock held.  In addition to that, you will also need:

  383035211c79 "ipmi: move message error checking to avoid deadlock"

to fix a bug in that change.

e1891cffd4c4 came in 5.1 and 383035211c79 came in 5.4 (and I believe was
backported) so everything should be good for 5.4 and later.  b4a34aa6d
was not backported to 4.14, so it is also ok.  So 4.19 is the only
kernel that needs the change.

Thanks to Janne Huttunen for quick work on this.

-corey