sched: Snapshot thread flags

mainline inclusion
from mainline-v5.17-rc1
commit 0569b245
category: performance
bugzilla: https://gitee.com/openeuler/kernel/issues/IA5WFA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=0569b245132c40015281610353935a50e282eb94



----------------------------------------------------------------------

Some thread flags can be set remotely, and so even when IRQs are disabled,
the flags can change under our feet. Generally this is unlikely to cause a
problem in practice, but it is somewhat unsound, and KCSAN will
legitimately warn that there is a data race.

To avoid such issues, a snapshot of the flags has to be taken prior to
using them. Some places already use READ_ONCE() for that, others do not.

Convert them all to the new flag accessor helpers.

The READ_ONCE(ti->flags) .. cmpxchg(ti->flags) loop in
set_nr_if_polling() is left as-is for clarity.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Paul E. McKenney <paulmck@kernel.org>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Link: https://lore.kernel.org/r/20211129130653.2037928-4-mark.rutland@arm.com



Conflict:
	kernel/sched/core.c

Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>