From: Zhi Yong Wu <wu...@linux.vnet.ibm.com>
The patch will introduce one set of rcu interface for seq_list.
Signed-off-by: Chandra Seetharaman <sekha...@us.ibm.com>
Signed-off-by: Zhi Yong Wu <wu...@linux.vnet.ibm.com>
---
fs/seq_file.c | 37 +++++++++++++++++++++++++++++++++++++
include/linux/seq_file.h | 7 +++++++
2 files changed, 44 insertions(+)
diff --git a/fs/seq_file.c b/fs/seq_file.c
index 774c1eb..301caa7 100644
--- a/fs/seq_file.c
+++ b/fs/seq_file.c
@@ -795,6 +795,43 @@ struct list_head *seq_list_next(void *v, struct list_head
*head, loff_t *ppos)
}
EXPORT_SYMBOL(seq_list_next);
+struct list_head *seq_list_start_rcu(struct list_head *head, loff_t pos)
+{
+ struct list_head *lh;
+
+ __list_for_each_rcu(lh, head)
+ if (pos-- == 0)
+ return lh;
+
+ return NULL;
+}
+EXPORT_SYMBOL(seq_list_start_rcu);
+
+struct list_head *seq_list_start_head_rcu(struct list_head *head, loff_t pos)
+{
+ if (!pos)
+ return head;
+
+ return seq_list_start_rcu(head, pos - 1);
+}
+EXPORT_SYMBOL(seq_list_start_head_rcu);
+
+struct list_head *seq_list_next_rcu(void *v, struct list_head *head,
+ loff_t *ppos)
+{
+ struct list_head *lh;
+
+ ++*ppos;
+ rcu_read_lock();
+ lh = rcu_dereference(((struct list_head *)v)->next);
+ if (lh == head)
+ lh = NULL;
+ rcu_read_unlock();
+
+ return lh;
+}
+EXPORT_SYMBOL(seq_list_next_rcu);
+
/**
* seq_hlist_start - start an iteration of a hlist
* @head: the head of the hlist
diff --git a/include/linux/seq_file.h b/include/linux/seq_file.h
index 2da29ac..7e391c9 100644
--- a/include/linux/seq_file.h
+++ b/include/linux/seq_file.h
@@ -155,6 +155,13 @@ extern struct list_head *seq_list_start_head(struct
list_head *head,
extern struct list_head *seq_list_next(void *v, struct list_head *head,
loff_t *ppos);
+extern struct list_head *seq_list_start_rcu(struct list_head *head,
+ loff_t pos);
+extern struct list_head *seq_list_start_head_rcu(struct list_head *head,
+ loff_t pos);
+extern struct list_head *seq_list_next_rcu(void *v, struct list_head *head,
+ loff_t *ppos);
+
/*
* Helpers for iteration over hlist_head-s in seq_files
*/
--
1.7.11.7
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