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authorLinus Torvalds <torvalds@linux-foundation.org>2008-12-28 12:49:40 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2008-12-28 12:49:40 -0800
commit0191b625ca5a46206d2fb862bb08f36f2fcb3b31 (patch)
tree454d1842b1833d976da62abcbd5c47521ebe9bd7 /include/linux/rculist_nulls.h
parent54a696bd07c14d3b1192d03ce7269bc59b45209a (diff)
parenteb56092fc168bf5af199d47af50c0d84a96db898 (diff)
Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next-2.6
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next-2.6: (1429 commits) net: Allow dependancies of FDDI & Tokenring to be modular. igb: Fix build warning when DCA is disabled. net: Fix warning fallout from recent NAPI interface changes. gro: Fix potential use after free sfc: If AN is enabled, always read speed/duplex from the AN advertising bits sfc: When disabling the NIC, close the device rather than unregistering it sfc: SFT9001: Add cable diagnostics sfc: Add support for multiple PHY self-tests sfc: Merge top-level functions for self-tests sfc: Clean up PHY mode management in loopback self-test sfc: Fix unreliable link detection in some loopback modes sfc: Generate unique names for per-NIC workqueues 802.3ad: use standard ethhdr instead of ad_header 802.3ad: generalize out mac address initializer 802.3ad: initialize ports LACPDU from const initializer 802.3ad: remove typedef around ad_system 802.3ad: turn ports is_individual into a bool 802.3ad: turn ports is_enabled into a bool 802.3ad: make ntt bool ixgbe: Fix set_ringparam in ixgbe to use the same memory pools. ... Fixed trivial IPv4/6 address printing conflicts in fs/cifs/connect.c due to the conversion to %pI (in this networking merge) and the addition of doing IPv6 addresses (from the earlier merge of CIFS).
Diffstat (limited to 'include/linux/rculist_nulls.h')
-rw-r--r--include/linux/rculist_nulls.h110
1 files changed, 110 insertions, 0 deletions
diff --git a/include/linux/rculist_nulls.h b/include/linux/rculist_nulls.h
new file mode 100644
index 00000000000..f9ddd03961a
--- /dev/null
+++ b/include/linux/rculist_nulls.h
@@ -0,0 +1,110 @@
+#ifndef _LINUX_RCULIST_NULLS_H
+#define _LINUX_RCULIST_NULLS_H
+
+#ifdef __KERNEL__
+
+/*
+ * RCU-protected list version
+ */
+#include <linux/list_nulls.h>
+#include <linux/rcupdate.h>
+
+/**
+ * hlist_nulls_del_init_rcu - deletes entry from hash list with re-initialization
+ * @n: the element to delete from the hash list.
+ *
+ * Note: hlist_nulls_unhashed() on the node return true after this. It is
+ * useful for RCU based read lockfree traversal if the writer side
+ * must know if the list entry is still hashed or already unhashed.
+ *
+ * In particular, it means that we can not poison the forward pointers
+ * that may still be used for walking the hash list and we can only
+ * zero the pprev pointer so list_unhashed() will return true after
+ * this.
+ *
+ * The caller must take whatever precautions are necessary (such as
+ * holding appropriate locks) to avoid racing with another
+ * list-mutation primitive, such as hlist_nulls_add_head_rcu() or
+ * hlist_nulls_del_rcu(), running on this same list. However, it is
+ * perfectly legal to run concurrently with the _rcu list-traversal
+ * primitives, such as hlist_nulls_for_each_entry_rcu().
+ */
+static inline void hlist_nulls_del_init_rcu(struct hlist_nulls_node *n)
+{
+ if (!hlist_nulls_unhashed(n)) {
+ __hlist_nulls_del(n);
+ n->pprev = NULL;
+ }
+}
+
+/**
+ * hlist_nulls_del_rcu - deletes entry from hash list without re-initialization
+ * @n: the element to delete from the hash list.
+ *
+ * Note: hlist_nulls_unhashed() on entry does not return true after this,
+ * the entry is in an undefined state. It is useful for RCU based
+ * lockfree traversal.
+ *
+ * In particular, it means that we can not poison the forward
+ * pointers that may still be used for walking the hash list.
+ *
+ * The caller must take whatever precautions are necessary
+ * (such as holding appropriate locks) to avoid racing
+ * with another list-mutation primitive, such as hlist_nulls_add_head_rcu()
+ * or hlist_nulls_del_rcu(), running on this same list.
+ * However, it is perfectly legal to run concurrently with
+ * the _rcu list-traversal primitives, such as
+ * hlist_nulls_for_each_entry().
+ */
+static inline void hlist_nulls_del_rcu(struct hlist_nulls_node *n)
+{
+ __hlist_nulls_del(n);
+ n->pprev = LIST_POISON2;
+}
+
+/**
+ * hlist_nulls_add_head_rcu
+ * @n: the element to add to the hash list.
+ * @h: the list to add to.
+ *
+ * Description:
+ * Adds the specified element to the specified hlist_nulls,
+ * while permitting racing traversals.
+ *
+ * The caller must take whatever precautions are necessary
+ * (such as holding appropriate locks) to avoid racing
+ * with another list-mutation primitive, such as hlist_nulls_add_head_rcu()
+ * or hlist_nulls_del_rcu(), running on this same list.
+ * However, it is perfectly legal to run concurrently with
+ * the _rcu list-traversal primitives, such as
+ * hlist_nulls_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().
+ */
+static inline void hlist_nulls_add_head_rcu(struct hlist_nulls_node *n,
+ struct hlist_nulls_head *h)
+{
+ struct hlist_nulls_node *first = h->first;
+
+ n->next = first;
+ n->pprev = &h->first;
+ rcu_assign_pointer(h->first, n);
+ if (!is_a_nulls(first))
+ first->pprev = &n->next;
+}
+/**
+ * hlist_nulls_for_each_entry_rcu - iterate over rcu list of given type
+ * @tpos: the type * to use as a loop cursor.
+ * @pos: the &struct hlist_nulls_node to use as a loop cursor.
+ * @head: the head for your list.
+ * @member: the name of the hlist_nulls_node within the struct.
+ *
+ */
+#define hlist_nulls_for_each_entry_rcu(tpos, pos, head, member) \
+ for (pos = rcu_dereference((head)->first); \
+ (!is_a_nulls(pos)) && \
+ ({ tpos = hlist_nulls_entry(pos, typeof(*tpos), member); 1; }); \
+ pos = rcu_dereference(pos->next))
+
+#endif
+#endif