[RFC PATCH 2/2 with seqcount v3] reservation: add suppport for read-only access using rcu

[Thomas Hellstrom]

On 04/29/2014 04:32 PM, Maarten Lankhorst wrote:
> op 23-04-14 13:15, Maarten Lankhorst schreef:
>> This adds 4 more functions to deal with rcu.
>>
>> reservation_object_get_fences_rcu() will obtain the list of shared
>> and exclusive fences without obtaining the ww_mutex.
>>
>> reservation_object_wait_timeout_rcu() will wait on all fences of the
>> reservation_object, without obtaining the ww_mutex.
>>
>> reservation_object_test_signaled_rcu() will test if all fences of the
>> reservation_object are signaled without using the ww_mutex.
>>
>> reservation_object_get_excl() is added because touching the fence_excl
>> member directly will trigger a sparse warning.
>>
>> Signed-off-by: Maarten Lankhorst <maarten.lankhorst at canonical.com>
>> ---
>> Using seqcount and fixing some lockdep bugs.
>> Changes since v2:
>> - Fix some crashes, remove some unneeded barriers when provided by
>> seqcount writes
>> - Fix code to work correctly with sparse's RCU annotations.
>> - Create a global string for the seqcount lock to make lockdep happy.
>>
>> Can I get this version reviewed? If it looks correct I'll mail the
>> full series
>> because it's intertwined with the TTM conversion to use this code.
> Ping, can anyone review this?

Hi, Maarten.
It's on my todo-list. Been away from office for a while.

/Thomas