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authorThomas Gleixner <tglx@linutronix.de>2016-07-04 09:50:27 +0000
committerIngo Molnar <mingo@kernel.org>2016-07-07 10:35:07 +0200
commit15dba1e37b5cfd7fab9bc84e0f05f35c918f4eef (patch)
tree9388b6b0c3347e48f4abfa59e35fe4bcde22bcc3 /include
parent2b1ecc3d1a6b10f8fbac7f83d80db30b5a2c2791 (diff)
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hlist: Add hlist_is_singular_node() helper
Required to figure out whether the entry is the only one in the hlist. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Arjan van de Ven <arjan@infradead.org> Cc: Chris Mason <clm@fb.com> Cc: Eric Dumazet <edumazet@google.com> Cc: George Spelvin <linux@sciencehorizons.net> Cc: Josh Triplett <josh@joshtriplett.org> Cc: Len Brown <lenb@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Cc: rt@linutronix.de Link: http://lkml.kernel.org/r/20160704094341.867631372@linutronix.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'include')
-rw-r--r--include/linux/list.h10
1 files changed, 10 insertions, 0 deletions
diff --git a/include/linux/list.h b/include/linux/list.h
index 5356f4d661a7..5183138aa932 100644
--- a/include/linux/list.h
+++ b/include/linux/list.h
@@ -679,6 +679,16 @@ static inline bool hlist_fake(struct hlist_node *h)
}
/*
+ * Check whether the node is the only node of the head without
+ * accessing head:
+ */
+static inline bool
+hlist_is_singular_node(struct hlist_node *n, struct hlist_head *h)
+{
+ return !n->next && n->pprev == &h->first;
+}
+
+/*
* Move a list from one list head to another. Fixup the pprev
* reference of the first entry if it exists.
*/