Commit 66655de6 authored by Li Zefan's avatar Li Zefan Committed by David S. Miller
Browse files

seq_file: Add helpers for iteration over a hlist 



Some places in kernel need to iterate over a hlist in seq_file,
so provide some common helpers.

Signed-off-by: default avatarLi Zefan <lizf@cn.fujitsu.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent b1109bf0

fs/seq_file.c

+56 −3
Original line number Diff line number Diff line
@@ -674,7 +674,6 @@ struct list_head *seq_list_start(struct list_head *head, loff_t pos) 


	return NULL;

}



EXPORT_SYMBOL(seq_list_start);



struct list_head *seq_list_start_head(struct list_head *head, loff_t pos)
@@ -684,7 +683,6 @@ struct list_head *seq_list_start_head(struct list_head *head, loff_t pos) 


	return seq_list_start(head, pos - 1);

}



EXPORT_SYMBOL(seq_list_start_head);



struct list_head *seq_list_next(void *v, struct list_head *head, loff_t *ppos)
@@ -695,5 +693,60 @@ struct list_head *seq_list_next(void *v, struct list_head *head, loff_t *ppos) 
	++*ppos;

	return lh == head ? NULL : lh;

}



EXPORT_SYMBOL(seq_list_next);



/**

 * seq_hlist_start - start an iteration of a hlist

 * @head: the head of the hlist

 * @pos:  the start position of the sequence

 *

 * Called at seq_file->op->start().

 */

struct hlist_node *seq_hlist_start(struct hlist_head *head, loff_t pos)

{

	struct hlist_node *node;



	hlist_for_each(node, head)

		if (pos-- == 0)

			return node;

	return NULL;

}

EXPORT_SYMBOL(seq_hlist_start);



/**

 * seq_hlist_start_head - start an iteration of a hlist

 * @head: the head of the hlist

 * @pos:  the start position of the sequence

 *

 * Called at seq_file->op->start(). Call this function if you want to

 * print a header at the top of the output.

 */

struct hlist_node *seq_hlist_start_head(struct hlist_head *head, loff_t pos)

{

	if (!pos)

		return SEQ_START_TOKEN;



	return seq_hlist_start(head, pos - 1);

}

EXPORT_SYMBOL(seq_hlist_start_head);



/**

 * seq_hlist_next - move to the next position of the hlist

 * @v:    the current iterator

 * @head: the head of the hlist

 * @pos:  the current posision

 *

 * Called at seq_file->op->next().

 */

struct hlist_node *seq_hlist_next(void *v, struct hlist_head *head,

				  loff_t *ppos)

{

	struct hlist_node *node = v;



	++*ppos;

	if (v == SEQ_START_TOKEN)

		return head->first;

	else

		return node->next;

}

EXPORT_SYMBOL(seq_hlist_next);

include/linux/seq_file.h

+11 −0
Original line number Diff line number Diff line
@@ -135,4 +135,15 @@ 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);



/*

 * Helpers for iteration over hlist_head-s in seq_files

 */



extern struct hlist_node *seq_hlist_start(struct hlist_head *head,

		loff_t pos);

extern struct hlist_node *seq_hlist_start_head(struct hlist_head *head,

		loff_t pos);

extern struct hlist_node *seq_hlist_next(void *v, struct hlist_head *head,

		loff_t *ppos);



#endif