linux-yocto-rt/4.19: fix merge conflict in lru_drain
Paul Gortmaker sent along the following fixup for 4.19-rt:
[
Author: Paul Gortmaker <paul.gortmaker@windriver.com>
Date: Mon Apr 15 12:01:31 2019 -0400
Revert "mm: handle lru_add_drain_all for UP properly"
This reverts commit
e6e9d6e290028b0a6b83b563fad9fafa7f1d515e.
It was a 4.19.31 backport of commit
6ea183d60c46 ("mm: handle
lru_add_drain_all for UP properly"). In summary, what that did
was to fix a possible harmless WARN_ON on non-SMP, introduced at
commit
4d43d395fed1 ("workqueue: Try to catch flush_work() without
INIT_WORK().") by adding non-SMP variants of lru functions.
The combination of that, with the -rt commit
473f14a9f234 ("mm:
perform lru_add_drain_all() remotely") at the merge of the two
results in the following build failure:
mm/swap.c:736:2: error: #endif without #if
since the -rt change wants RT specific lru and the stable backport
wants non-SMP specific lru, and a chunk of the backport with
an #ifdef CONFIG_SMP is missing.
However, before we add a four way cluster of ifdeffery to handle all
cases, we note
4d43d395fed1 was added to the v5.1 release, and it
was not (currently) backported to any 4.19.x stable release - so it is
unclear to me why this commit was ever backported to 4.19.31 at all.
Further, we note this change was to mm/swap.c -- and by definition,
any preempt-rt deployment that uses swap for anything other than a
failure contingency mitigation is broken by design.
Given all that, I decided that the best path forward was to revert
the two of the three chunks of the backport that remain in the -rt
branch, and return us to the pre-4.19.31 merge behaviour for -rt.
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
]
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Bruce Ashfield <bruce.ashfield@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
Signed-off-by: Armin Kuster <akuster808@gmail.com>
