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authorShaohua Li <shli@kernel.org>2013-10-15 09:05:02 +0800
committerJens Axboe <axboe@kernel.dk>2013-10-25 11:55:59 +0100
commit7fc2ba17e8bf9f218cac10cc2a3de613d9d9086d (patch)
tree464baa951977743dc1da2dd1a0f595c50dc3e0a8
parente26b53d0b287056646a0dffce8bc6b0f053f3823 (diff)
downloadop-kernel-dev-7fc2ba17e8bf9f218cac10cc2a3de613d9d9086d.zip
op-kernel-dev-7fc2ba17e8bf9f218cac10cc2a3de613d9d9086d.tar.gz
percpu_ida: add percpu_ida_for_each_free
Add a new API to iterate free ids. blk-mq-tag will use it. Note, this doesn't guarantee to iterate all free ids restrictly. Caller should be aware of this. blk-mq uses it to do sanity check for request timedout, so can tolerate the limitation. Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Shaohua Li <shli@fusionio.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
-rw-r--r--include/linux/percpu_ida.h4
-rw-r--r--lib/percpu_ida.c44
2 files changed, 48 insertions, 0 deletions
diff --git a/include/linux/percpu_ida.h b/include/linux/percpu_ida.h
index 56c1403..63510ae 100644
--- a/include/linux/percpu_ida.h
+++ b/include/linux/percpu_ida.h
@@ -73,4 +73,8 @@ static inline int percpu_ida_init(struct percpu_ida *pool, unsigned long nr_tags
IDA_DEFAULT_PCPU_BATCH_MOVE);
}
+typedef int (*percpu_ida_cb)(unsigned, void *);
+int percpu_ida_for_each_free(struct percpu_ida *pool, percpu_ida_cb fn,
+ void *data);
+
#endif /* __PERCPU_IDA_H__ */
diff --git a/lib/percpu_ida.c b/lib/percpu_ida.c
index a601d42..0f51c1b 100644
--- a/lib/percpu_ida.c
+++ b/lib/percpu_ida.c
@@ -327,3 +327,47 @@ err:
return -ENOMEM;
}
EXPORT_SYMBOL_GPL(__percpu_ida_init);
+
+/**
+ * percpu_ida_for_each_free - iterate free ids of a pool
+ * @pool: pool to iterate
+ * @fn: interate callback function
+ * @data: parameter for @fn
+ *
+ * Note, this doesn't guarantee to iterate all free ids restrictly. Some free
+ * ids might be missed, some might be iterated duplicated, and some might
+ * be iterated and not free soon.
+ */
+int percpu_ida_for_each_free(struct percpu_ida *pool, percpu_ida_cb fn,
+ void *data)
+{
+ unsigned long flags;
+ struct percpu_ida_cpu *remote;
+ unsigned cpu, i, err = 0;
+
+ local_irq_save(flags);
+ for_each_possible_cpu(cpu) {
+ remote = per_cpu_ptr(pool->tag_cpu, cpu);
+ spin_lock(&remote->lock);
+ for (i = 0; i < remote->nr_free; i++) {
+ err = fn(remote->freelist[i], data);
+ if (err)
+ break;
+ }
+ spin_unlock(&remote->lock);
+ if (err)
+ goto out;
+ }
+
+ spin_lock(&pool->lock);
+ for (i = 0; i < pool->nr_free; i++) {
+ err = fn(pool->freelist[i], data);
+ if (err)
+ break;
+ }
+ spin_unlock(&pool->lock);
+out:
+ local_irq_restore(flags);
+ return err;
+}
+EXPORT_SYMBOL_GPL(percpu_ida_for_each_free);
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