• A
    [PATCH] cpu hotplug: fix locking in cpufreq drivers · 90d45d17
    Ashok Raj 提交于
    When calling target drivers to set frequency, we take cpucontrol lock.
    When we modified the code to accomodate CPU hotplug, there was an attempt
    to take a double lock of cpucontrol leading to a deadlock.  Since the
    current thread context is already holding the cpucontrol lock, we dont need
    to make another attempt to acquire it.
    
    Now we leave a trace in current->flags indicating current thread already is
    under cpucontrol lock held, so we dont attempt to do this another time.
    
    Thanks to Andrew Morton for the beating:-)
    
    From: Brice Goglin <Brice.Goglin@ens-lyon.org>
    
      Build fix
    
    (akpm: this patch is still unpleasant.  Ashok continues to look for a cleaner
    solution, doesn't he?  ;))
    Signed-off-by: NAshok Raj <ashok.raj@intel.com>
    Signed-off-by: NBrice Goglin <Brice.Goglin@ens-lyon.org>
    Signed-off-by: NAndrew Morton <akpm@osdl.org>
    Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
    90d45d17
sched.h 44.7 KB