提交 4c925a45 编写于 作者: N Nathan Lynch 提交者: Xie XiuQi

powerpc/pseries/hibernation: drop pseries_suspend_begin() from suspend ops

stable inclusion
from stable-5.10.4
commit b155175979e165803b8ab8d2c476f6a005166e5f
bugzilla: 46903

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

[ Upstream commit 52719fce ]

There are three ways pseries_suspend_begin() can be reached:

1. When "mem" is written to /sys/power/state:

kobj_attr_store()
-> state_store()
  -> pm_suspend()
    -> suspend_devices_and_enter()
      -> pseries_suspend_begin()

This never works because there is no way to supply a valid stream id
using this interface, and H_VASI_STATE is called with a stream id of
zero. So this call path is useless at best.

2. When a stream id is written to /sys/devices/system/power/hibernate.
pseries_suspend_begin() is polled directly from store_hibernate()
until the stream is in the "Suspending" state (i.e. the platform is
ready for the OS to suspend execution):

dev_attr_store()
-> store_hibernate()
  -> pseries_suspend_begin()

3. When a stream id is written to /sys/devices/system/power/hibernate
(continued). After #2, pseries_suspend_begin() is called once again
from the pm core:

dev_attr_store()
-> store_hibernate()
  -> pm_suspend()
    -> suspend_devices_and_enter()
      -> pseries_suspend_begin()

This is redundant because the VASI suspend state is already known to
be Suspending.

The begin() callback of platform_suspend_ops is optional, so we can
simply remove that assignment with no loss of function.

Fixes: 32d8ad4e ("powerpc/pseries: Partition hibernation support")
Signed-off-by: NNathan Lynch <nathanl@linux.ibm.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201207215200.1785968-18-nathanl@linux.ibm.comSigned-off-by: NSasha Levin <sashal@kernel.org>
Signed-off-by: NChen Jun <chenjun102@huawei.com>
Acked-by: NXie XiuQi <xiexiuqi@huawei.com>
上级 7e818fd0
......@@ -187,7 +187,6 @@ static struct bus_type suspend_subsys = {
static const struct platform_suspend_ops pseries_suspend_ops = {
.valid = suspend_valid_only_mem,
.begin = pseries_suspend_begin,
.prepare_late = pseries_prepare_late,
.enter = pseries_suspend_enter,
};
......
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