mm/vmpressure.c: fix race in vmpressure_work_fn()
mm/vmpressure.c: fix race in vmpressure_work_fn()

In some android devices, there will be a "divide by zero" exception.
vmpr->scanned could be zero before spin_lock(&vmpr->sr_lock).

Addresses https://bugzilla.kernel.org/show_bug.cgi?id=88051

[5c1e68b099950c134891f0b6e179498a8ebe9cf9@linux-foundation.org: neaten]
Reported-by: ji_ang <a6ce59e9760494e639a59e2601fb1f60fa8b7be9@163.com>
Cc: Anton Vorontsov <1aae5ab9541d66245293c8fc1b9880f5df073631@linaro.org>
Cc: <4fbacc2fa0ffdbb11bf1ad6925b886ebd08dd15f@vger.kernel.org>
Signed-off-by: Andrew Morton <5c1e68b099950c134891f0b6e179498a8ebe9cf9@linux-foundation.org>
Signed-off-by: Linus Torvalds <69652caca27c8b940640ad396ab71f93cacec34f@linux-foundation.org>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs