[PATCH] ring_buffer: use list_replace() in rb_get_reader_page()

From: Xiao Guangrong
Date: Sun May 24 2009 - 23:58:14 EST


Use list_replace() to splice list in rb_get_reader_page()

[ Impact: cleanup ]

Signed-off-by: Xiao Guangrong <xiaoguangrong@xxxxxxxxxxxxxx>
---
kernel/trace/ring_buffer.c | 12 ++----------
1 files changed, 2 insertions(+), 10 deletions(-)

diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index f558b37..f88bfcc 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -2179,22 +2179,14 @@ rb_get_reader_page(struct ring_buffer_per_cpu *cpu_buffer)
if (cpu_buffer->commit_page == cpu_buffer->reader_page)
goto out;

- /*
- * Splice the empty reader page into the list around the head.
- * Reset the reader page to size zero.
- */
-
+ /* Reset the reader page to size zero */
reader = cpu_buffer->head_page;
- cpu_buffer->reader_page->list.next = reader->list.next;
- cpu_buffer->reader_page->list.prev = reader->list.prev;
-
local_set(&cpu_buffer->reader_page->write, 0);
local_set(&cpu_buffer->reader_page->entries, 0);
local_set(&cpu_buffer->reader_page->page->commit, 0);

/* Make the reader page now replace the head */
- reader->list.prev->next = &cpu_buffer->reader_page->list;
- reader->list.next->prev = &cpu_buffer->reader_page->list;
+ list_replace(&reader->list, &cpu_buffer->reader_page->list);

/*
* If the tail is on the reader, then we must set the head
--
1.6.1.2


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