From cc1b20049cd8d2f3bc2fb9d736281410b6f96fc3 Mon Sep 17 00:00:00 2001 From: Nicolas Pitre Date: Mon, 26 Nov 2012 22:48:55 -0500 Subject: ARM: bL_switcher: veto CPU hotplug requests when the switcher is active Trying to support both the switcher and CPU hotplug at the same time is quickly becoming very complex for little gain. So let's simply veto any hotplug requests when the switcher is active. This restriction might be loosened a bit eventually. Signed-off-by: Nicolas Pitre --- arch/arm/common/bL_switcher.c | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) diff --git a/arch/arm/common/bL_switcher.c b/arch/arm/common/bL_switcher.c index 00a4ce23d91..fe13ce456af 100644 --- a/arch/arm/common/bL_switcher.c +++ b/arch/arm/common/bL_switcher.c @@ -530,6 +530,25 @@ static int __init bL_switcher_sysfs_init(void) #endif /* CONFIG_SYSFS */ +/* + * Veto any CPU hotplug operation while the switcher is active. + * We're just not ready to deal with that given the trickery involved. + */ +static int bL_switcher_hotplug_callback(struct notifier_block *nfb, + unsigned long action, void *hcpu) +{ + switch (action) { + case CPU_UP_PREPARE: + case CPU_DOWN_PREPARE: + if (bL_switcher_active) + return NOTIFY_BAD; + } + return NOTIFY_DONE; +} + +static struct notifier_block bL_switcher_hotplug_notifier = + { &bL_switcher_hotplug_callback, NULL, 0 }; + static bool no_bL_switcher; core_param(no_bL_switcher, no_bL_switcher, bool, 0644); @@ -542,6 +561,8 @@ static int __init bL_switcher_init(void) return -EINVAL; } + register_cpu_notifier(&bL_switcher_hotplug_notifier); + if (!no_bL_switcher) { ret = bL_switcher_enable(); if (ret) -- cgit v1.2.3