From: Vitaly Kuznetsov Date: Wed, 5 Aug 2015 07:52:46 +0000 (-0700) Subject: cpu-hotplug: convert cpu_hotplug_disabled to a counter X-Git-Tag: omap-for-v4.3/fixes-merge-window~46^2~49 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=89af7ba5740b5937d10c8de93e79e71e5a933041;p=pandora-kernel.git cpu-hotplug: convert cpu_hotplug_disabled to a counter As a prerequisite to exporting cpu_hotplug_enable/cpu_hotplug_disable functions to modules we need to convert cpu_hotplug_disabled to a counter to properly support disable -> disable -> enable call sequences. E.g. after Hyper-V vmbus module (which is supposed to be the first user of exported cpu_hotplug_enable/cpu_hotplug_disable) did cpu_hotplug_disable() hibernate path calls disable_nonboot_cpus() and if we hit an error in _cpu_down() enable_nonboot_cpus() will be called on the failure path (thus making cpu_hotplug_disabled = 0 and leaving cpu hotplug in 'enabled' state). Same problem is possible if more than 1 module use cpu_hotplug_disable/cpu_hotplug_enable on their load/unload paths. When one of these modules is been unloaded it is logical to leave cpu hotplug in 'disabled' state. To support the change we need to increse cpu_hotplug_disabled counter in disable_nonboot_cpus() unconditionally as all users of disable_nonboot_cpus() are supposed to do enable_nonboot_cpus() in case an error was returned. Signed-off-by: Vitaly Kuznetsov Reviewed-by: Thomas Gleixner Signed-off-by: K. Y. Srinivasan Signed-off-by: Greg Kroah-Hartman --- Reading git-diff-tree failed