[PATCH 1/7] Introduce delete_from_page_cache

From: Minchan Kim
Date: Wed Dec 22 2010 - 10:33:40 EST


This function works as just wrapper remove_from_page_cache.
The difference is that it decreases page references in itself.
So caller have to make sure it has a page reference before calling.

This patch is ready for removing remove_from_page_cache.

Cc: Christoph Hellwig <hch@xxxxxxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Signed-off-by: Minchan Kim <minchan.kim@xxxxxxxxx>
---
include/linux/pagemap.h | 1 +
mm/filemap.c | 17 +++++++++++++++++
2 files changed, 18 insertions(+), 0 deletions(-)

diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index 9c66e99..7a1cb49 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -457,6 +457,7 @@ int add_to_page_cache_lru(struct page *page, struct address_space *mapping,
pgoff_t index, gfp_t gfp_mask);
extern void remove_from_page_cache(struct page *page);
extern void __remove_from_page_cache(struct page *page);
+extern void delete_from_page_cache(struct page *page);

/*
* Like add_to_page_cache_locked, but used to add newly allocated pages:
diff --git a/mm/filemap.c b/mm/filemap.c
index 095c393..1ca7475 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -166,6 +166,23 @@ void remove_from_page_cache(struct page *page)
}
EXPORT_SYMBOL(remove_from_page_cache);

+/**
+ * delete_from_page_cache - delete page from page cache
+ *
+ * @page: the page which the kernel is trying to remove from page cache
+ *
+ * This must be called only on pages that have
+ * been verified to be in the page cache and locked.
+ * It will never put the page into the free list,
+ * the caller has a reference on the page.
+ */
+void delete_from_page_cache(struct page *page)
+{
+ remove_from_page_cache(page);
+ page_cache_release(page);
+}
+EXPORT_SYMBOL(delete_from_page_cache);
+
static int sync_page(void *word)
{
struct address_space *mapping;
--
1.7.0.4

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