Re: [patch V4 02/10] rtmutex: Simplify rtmutex_slowtrylock()

[Lai Jiangshan]

On 06/12/2014 02:44 AM, Thomas Gleixner wrote:
> Oleg noticed that rtmutex_slowtrylock() has a pointless check for
> rt_mutex_owner(lock) != current.
> 
> To avoid calling try_to_take_rtmutex() we really want to check whether
> the lock has an owner at all or whether the trylock failed because the
> owner is NULL, but the RT_MUTEX_HAS_WAITERS bit is set. This covers
> the lock is owned by caller situation as well.
> 
> We can actually do this check lockless. trylock is taking a chance
> whether we take lock->wait_lock to do the check or not.
> 
> Add comments to the function while at it.
> 
> Reported-by: Oleg Nesterov <oleg@xxxxxxxxxx>
> Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> ---

Reviewed-by: Lai Jiangshan <laijs@xxxxxxxxxxxxxx>

Thanks,
Lai
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