Make common helpers for seq_files that work with list_heads

Many places in kernel use seq_file API to iterate over a regular list_head.
The code for such iteration is identical in all the places, so it's worth
introducing a common helpers.

This makes code about 300 lines smaller:

The first version of this patch made the helper functions static inline
in the seq_file.h header. This patch moves them to the fs/seq_file.c as
Andrew proposed. The vmlinux .text section sizes are as follows:

2.6.22-rc1-mm1:              0x001794d5
with the previous version:   0x00179505
with this patch:             0x00179135

The config file used was make allnoconfig with the "y" inclusion of all
the possible options to make the files modified by the patch compile plus
drivers I have on the test node.

This patch:

Many places in kernel use seq_file API to iterate over a regular list_head.
The code for such iteration is identical in all the places, so it's worth
introducing a common helpers.

Signed-off-by: Pavel Emelianov <xemul@openvz.org>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 11 insertions, 0 deletions

diff --git a/include/linux/seq_file.h b/include/linux/seq_file.h
index 3e3cccbb1ca..83783ab0f55 100644
--- a/include/linux/seq_file.h
+++ b/include/linux/seq_file.h
@@ -50,5 +50,16 @@ int seq_release_private(struct inode *, struct file *);
 
 #define SEQ_START_TOKEN ((void *)1)
 
+/*
+ * Helpers for iteration over list_head-s in seq_files
+ */
+
+extern struct list_head *seq_list_start(struct list_head *head,
+		loff_t pos);
+extern struct list_head *seq_list_start_head(struct list_head *head,
+		loff_t pos);
+extern struct list_head *seq_list_next(void *v, struct list_head *head,
+		loff_t *ppos);
+
 #endif
 #endif