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

From: Maarten Lankhorst
Date: Tue Apr 29 2014 - 10:32:48 EST


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@xxxxxxxxxxxxx>
---
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?
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