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author | David S. Miller <davem@davemloft.net> | 2014-11-01 18:53:27 (GMT) |
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committer | David S. Miller <davem@davemloft.net> | 2014-11-01 18:53:27 (GMT) |
commit | 55b42b5ca2dcf143465968697fe6c6503b05fca1 (patch) | |
tree | 91878cd53efc44ba67244d4d3897020828c87c01 /kernel/cpu.c | |
parent | 10738eeaf4ab3de092586cefcc082e7d43ca0044 (diff) | |
parent | ec1f1276022e4e3ca40871810217d513e39ff250 (diff) | |
download | linux-55b42b5ca2dcf143465968697fe6c6503b05fca1.tar.xz |
Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
Conflicts:
drivers/net/phy/marvell.c
Simple overlapping changes in drivers/net/phy/marvell.c
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'kernel/cpu.c')
-rw-r--r-- | kernel/cpu.c | 14 |
1 files changed, 13 insertions, 1 deletions
diff --git a/kernel/cpu.c b/kernel/cpu.c index 356450f..90a3d01 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -64,6 +64,8 @@ static struct { * an ongoing cpu hotplug operation. */ int refcount; + /* And allows lockless put_online_cpus(). */ + atomic_t puts_pending; #ifdef CONFIG_DEBUG_LOCK_ALLOC struct lockdep_map dep_map; @@ -113,7 +115,11 @@ void put_online_cpus(void) { if (cpu_hotplug.active_writer == current) return; - mutex_lock(&cpu_hotplug.lock); + if (!mutex_trylock(&cpu_hotplug.lock)) { + atomic_inc(&cpu_hotplug.puts_pending); + cpuhp_lock_release(); + return; + } if (WARN_ON(!cpu_hotplug.refcount)) cpu_hotplug.refcount++; /* try to fix things up */ @@ -155,6 +161,12 @@ void cpu_hotplug_begin(void) cpuhp_lock_acquire(); for (;;) { mutex_lock(&cpu_hotplug.lock); + if (atomic_read(&cpu_hotplug.puts_pending)) { + int delta; + + delta = atomic_xchg(&cpu_hotplug.puts_pending, 0); + cpu_hotplug.refcount -= delta; + } if (likely(!cpu_hotplug.refcount)) break; __set_current_state(TASK_UNINTERRUPTIBLE); |