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    Subject[tip:smp/hotplug] ACPI/processor: Avoid STARTING/DYING actions in a more logical way
    Commit-ID:  e1272f541c6ad476426ef24b56b4e1d3403db513
    Gitweb: http://git.kernel.org/tip/e1272f541c6ad476426ef24b56b4e1d3403db513
    Author: Richard Cochran <rcochran@linutronix.de>
    AuthorDate: Wed, 13 Jul 2016 17:16:38 +0000
    Committer: Ingo Molnar <mingo@kernel.org>
    CommitDate: Fri, 15 Jul 2016 10:40:24 +0200

    ACPI/processor: Avoid STARTING/DYING actions in a more logical way

    As part of the hotplug cleanup, the CPU_STARTING/DYING actions are going
    away soon. This driver needlessly uses those two macro, and so this patch
    replaces that code with something more sensible.

    Commit:

    8da8373447d6a57a5a9f55233d35beb15d92d0d2 ("ACPI / processor: Fix STARTING/DYING action in acpi_cpu_soft_notify()")

    added checks for those two actions, because the notification callback can
    sleep, causing a hung CPU. This patch instead checks for the ONLINE/DEAD
    actions, which are the ones that are handled by the driver in the first
    place.

    Signed-off-by: Richard Cochran <rcochran@linutronix.de>
    Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de>
    Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
    Cc: Len Brown <lenb@kernel.org>
    Cc: Linus Torvalds <torvalds@linux-foundation.org>
    Cc: Peter Zijlstra <peterz@infradead.org>
    Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
    Cc: Thomas Gleixner <tglx@linutronix.de>
    Cc: linux-acpi@vger.kernel.org
    Cc: rt@linutronix.de
    Link: http://lkml.kernel.org/r/20160713153335.964962885@linutronix.de
    Signed-off-by: Ingo Molnar <mingo@kernel.org>
    ---
    drivers/acpi/processor_driver.c | 11 ++++++-----
    1 file changed, 6 insertions(+), 5 deletions(-)

    diff --git a/drivers/acpi/processor_driver.c b/drivers/acpi/processor_driver.c
    index d2fa8cb..eecdb19 100644
    --- a/drivers/acpi/processor_driver.c
    +++ b/drivers/acpi/processor_driver.c
    @@ -118,12 +118,13 @@ static int acpi_cpu_soft_notify(struct notifier_block *nfb,
    struct acpi_device *device;
    action &= ~CPU_TASKS_FROZEN;

    - /*
    - * CPU_STARTING and CPU_DYING must not sleep. Return here since
    - * acpi_bus_get_device() may sleep.
    - */
    - if (action == CPU_STARTING || action == CPU_DYING)
    + switch (action) {
    + case CPU_ONLINE:
    + case CPU_DEAD:
    + break;
    + default:
    return NOTIFY_DONE;
    + }

    if (!pr || acpi_bus_get_device(pr->handle, &device))
    return NOTIFY_DONE;
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