Provided by:
linux-doc-2.6.15_2.6.15-23.39_all 
NAME
hlist_add_head_rcu - adds the specified element to the specified hlist,
SYNOPSIS
void hlist_add_head_rcu (struct hlist_node * n,
struct hlist_head * h);
ARGUMENTS
n the element to add to the hash list.
h the list to add to.
DESCRIPTION
The caller must take whatever precautions are necessary (such as
holding appropriate locks) to avoid racing with another list-mutation
primitive, such as hlist_add_head_rcu or hlist_del_rcu, running on this
same list. However, it is perfectly legal to run concurrently with the
_rcu list-traversal primitives, such as hlist_for_each_entry_rcu, used
to prevent memory-consistency problems on Alpha CPUs. Regardless of the
type of CPU, the list-traversal primitive must be guarded by
rcu_read_lock.
DESCRIPTION
The caller must take whatever precautions are necessary (such as
holding appropriate locks) to avoid racing with another list-mutation
primitive, such as hlist_add_head_rcu or hlist_del_rcu, running on this
same list. However, it is perfectly legal to run concurrently with the
_rcu list-traversal primitives, such as hlist_for_each_entry_rcu, used
to prevent memory-consistency problems on Alpha CPUs. Regardless of the
type of CPU, the list-traversal primitive must be guarded by
rcu_read_lock.