From: Michael Ellerman Date: Mon, 4 Apr 2011 20:57:27 +0000 (+0000) Subject: powerpc/nohash: Allocate stale_map[cpu] on CPU_UP_PREPARE not CPU_ONLINE X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=f5be2dc0bd8d27a39d84a89e4ff90ba38cd2b285;p=GitHub%2FLineageOS%2FG12%2Fandroid_kernel_amlogic_linux-4.9.git powerpc/nohash: Allocate stale_map[cpu] on CPU_UP_PREPARE not CPU_ONLINE Currently we allocate the stale_map for a cpu when it comes online, this leaves open a small window where a process can be scheduled on the cpu before the stale_map is allocated. Instead allocate the stale_map at CPU_UP_PREPARE time, that way it will be always available before tasks start running. It is possible the cpu fails to come up, in which case we should free the stale_map, so add a CPU_UP_CANCELED case to do that. Signed-off-by: Michael Ellerman Signed-off-by: Benjamin Herrenschmidt --- diff --git a/arch/powerpc/mm/mmu_context_nohash.c b/arch/powerpc/mm/mmu_context_nohash.c index c0aab52da3a5..4d8fa911c73d 100644 --- a/arch/powerpc/mm/mmu_context_nohash.c +++ b/arch/powerpc/mm/mmu_context_nohash.c @@ -338,12 +338,14 @@ static int __cpuinit mmu_context_cpu_notify(struct notifier_block *self, return NOTIFY_OK; switch (action) { - case CPU_ONLINE: - case CPU_ONLINE_FROZEN: + case CPU_UP_PREPARE: + case CPU_UP_PREPARE_FROZEN: pr_devel("MMU: Allocating stale context map for CPU %d\n", cpu); stale_map[cpu] = kzalloc(CTX_MAP_SIZE, GFP_KERNEL); break; #ifdef CONFIG_HOTPLUG_CPU + case CPU_UP_CANCELED: + case CPU_UP_CANCELED_FROZEN: case CPU_DEAD: case CPU_DEAD_FROZEN: pr_devel("MMU: Freeing stale context map for CPU %d\n", cpu);