mm, memcg: Prevent memory.soft_limit_in_bytes load/store tearing

The knob for cgroup v1 memory controller: memory.soft_limit_in_bytes is
not protected by any locking so it can be modified while it is used.  This
is not an actual problem because races are unlikely.  But it is better to
use [READ|WRITE]_ONCE to prevent compiler from doing anything funky.

The access of memcg->soft_limit is lockless, so it can be concurrently set
at the same time as we are trying to read it.  All occurrences of
memcg->soft_limit are updated with [READ|WRITE]_ONCE.

[[email protected]: v3]
  Link: https://lkml.kernel.org/r/[email protected]
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Yue Zhao <[email protected]>
Acked-by: Shakeel Butt <[email protected]>
Acked-by: Roman Gushchin <[email protected]>
Acked-by: Michal Hocko <[email protected]>
Cc: Johannes Weiner <[email protected]>
Cc: Matthew Wilcox (Oracle) <[email protected]>
Cc: Muchun Song <[email protected]>
Cc: Tang Yizhou <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

0 files changed, 0 insertions, 0 deletions