From bcf67e16251c42302499499b1c50f7d35622f564 Mon Sep 17 00:00:00 2001 From: Pavel Emelianov Date: Tue, 10 Jul 2007 17:22:26 -0700 Subject: [PATCH] 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 Cc: "David S. Miller" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/seq_file.c | 34 ++++++++++++++++++++++++++++++++++ include/linux/seq_file.h | 11 +++++++++++ 2 files changed, 45 insertions(+) diff --git a/fs/seq_file.c b/fs/seq_file.c index 0ac22af7afe5..49194a4e6b91 100644 --- a/fs/seq_file.c +++ b/fs/seq_file.c @@ -447,3 +447,37 @@ int seq_puts(struct seq_file *m, const char *s) return -1; } EXPORT_SYMBOL(seq_puts); + +struct list_head *seq_list_start(struct list_head *head, loff_t pos) +{ + struct list_head *lh; + + list_for_each(lh, head) + if (pos-- == 0) + return lh; + + return NULL; +} + +EXPORT_SYMBOL(seq_list_start); + +struct list_head *seq_list_start_head(struct list_head *head, loff_t pos) +{ + if (!pos) + return head; + + 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) +{ + struct list_head *lh; + + lh = ((struct list_head *)v)->next; + ++*ppos; + return lh == head ? NULL : lh; +} + +EXPORT_SYMBOL(seq_list_next); diff --git a/include/linux/seq_file.h b/include/linux/seq_file.h index 3e3cccbb1cac..83783ab0f552 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