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    SubjectRe: [PATCH] NFS: Fix RCU warnings in nfs_inode_return_delegation_noreclaim() [ver #2]
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    Le lundi 29 mars 2010 à 21:15 +0100, David Howells a écrit :
    > My objection to using rcu_dereference_check() here is that it's a dynamic
    > check: the compiler emits code to do it, since the lock/unlock status of what
    > the pointer points to cannot be determined easily at compiler time - and then
    > the barrier is interpolated anyway unnecessarily.
    >

    Then in this case, use either a condition ORing all possibilities,
    or just use rcu_dereference_raw() because its just too complex ?

    ptr = rcu_dereference_check(xxx->ptr,
    rcu_read_lock_held() ||
    lockdep_is_held(&some_global_lock) ||
    lockdep_is_held(&xxx->lock));

    OR

    /* This is too complex to check what protects us at this point */
    ptr = rcu_dereference_raw(xxx->ptr);



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