[patch 3/4] percpu_ida: add an API to return free tags

[Shaohua Li]

add an API to return free tags, blk-mq-tag will use it

Signed-off-by: Shaohua Li <shli@xxxxxxxxxxxx>
---
 include/linux/percpu_ida.h |    1 +
 lib/percpu_ida.c           |   17 +++++++++++++++++
 2 files changed, 18 insertions(+)

Index: master/include/linux/percpu_ida.h
===================================================================
--- master.orig/include/linux/percpu_ida.h	2013-10-11 12:15:06.996416710 +0800
+++ master/include/linux/percpu_ida.h	2013-10-11 12:15:06.992416749 +0800
@@ -76,4 +76,5 @@ static inline int percpu_ida_init(struct
 int percpu_ida_for_each_free(struct percpu_ida *pool,
 	int (*fn)(int id, void *data), void *data);
 
+unsigned percpu_ida_free_tags(struct percpu_ida *pool, int cpu);
 #endif /* __PERCPU_IDA_H__ */
Index: master/lib/percpu_ida.c
===================================================================
--- master.orig/lib/percpu_ida.c	2013-10-11 12:15:06.996416710 +0800
+++ master/lib/percpu_ida.c	2013-10-11 12:15:06.992416749 +0800
@@ -371,3 +371,20 @@ out:
 	return err;
 }
 EXPORT_SYMBOL_GPL(percpu_ida_for_each_free);
+
+/**
+ * percpu_ida_free_tags - return free tags number of a specific cpu or global pool
+ * @pool: pool related
+ * @cpu: specific cpu or global pool if @cpu == nr_cpu_ids
+ *
+ * Note: this just returns a snapshot of free tags number.
+ */
+unsigned percpu_ida_free_tags(struct percpu_ida *pool, int cpu)
+{
+	struct percpu_ida_cpu *remote;
+	if (cpu == nr_cpu_ids)
+		return pool->nr_free;
+	remote = per_cpu_ptr(pool->tag_cpu, cpu);
+	return remote->nr_free;
+}
+EXPORT_SYMBOL_GPL(percpu_ida_free_tags);

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