mainline inclusion
from mainline-a9659476 undefined
commit a9659476
category: bugfix
bugzilla: 18481
CVE: NA

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

When failslab was originally written, the intention of the
"ignore-gfp-wait" flag default value ("N") was to fail GFP_ATOMIC
allocations.  Those were defined as (__GFP_HIGH), and the code would test
for __GFP_WAIT (0x10u).

However, since then, __GFP_WAIT was replaced by __GFP_RECLAIM
(___GFP_DIRECT_RECLAIM|___GFP_KSWAPD_RECLAIM), and GFP_ATOMIC is now
defined as (__GFP_HIGH|__GFP_ATOMIC|__GFP_KSWAPD_RECLAIM).

This means that when the flag is false, almost no allocation ever fails
(as even GFP_ATOMIC allocations contain ___GFP_KSWAPD_RECLAIM).

Restore the original intent of the code, by ignoring calls that directly
reclaim only (__GFP_DIRECT_RECLAIM), and thus, failing GFP_ATOMIC calls
again by default.

Link: http://lkml.kernel.org/r/20190520214514.81360-1-drinkcat@chromium.org
Fixes: 71baba4b ("mm, page_alloc: rename __GFP_WAIT to __GFP_RECLAIM")
Signed-off-by: NNicolas Boichat <drinkcat@chromium.org>
Reviewed-by: NAkinobu Mita <akinobu.mita@gmail.com>
Acked-by: NDavid Rientjes <rientjes@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NChenwandun <chenwandun@huawei.com>
Reviewed-by: NKefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>