The raid456_cpu_notify() hotplug callback lacks handling of the
CPU_UP_CANCELED case. That means if CPU_UP_PREPARE fails, the scratch
buffer is leaked.
Add handling for CPU_UP_CANCELED[_FROZEN] hotplug notifier transitions
to free the scratch buffer.
CC: Shaohua Li <shli@kernel.org> CC: linux-raid@vger.kernel.org Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de> Signed-off-by: Shaohua Li <shli@fb.com>