From 03572a49ecc93af1ccd61258f0b0e4ec1874c889 Mon Sep 17 00:00:00 2001
From: Jens Axboe <axboe@suse.de>
Date: Thu, 27 Apr 2006 08:46:01 +0200
Subject: [PATCH] --- yaml --- r: 26222 b: refs/heads/master c:
 ebf43500ef148a380bd132743c3fc530111ac620 h: refs/heads/master v: v3

---
 [refs]                        |  2 +-
 trunk/include/linux/pagemap.h |  2 ++
 trunk/mm/filemap.c            | 32 ++++++++++++++++++++++++++++++++
 3 files changed, 35 insertions(+), 1 deletion(-)

diff --git a/[refs] b/[refs]
index 3970cfba6593..e110010d20a4 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: eb645a24de82496434cc81171d7f350edb327399
+refs/heads/master: ebf43500ef148a380bd132743c3fc530111ac620
diff --git a/trunk/include/linux/pagemap.h b/trunk/include/linux/pagemap.h
index 9539efd4f7e6..7a1af574dedf 100644
--- a/trunk/include/linux/pagemap.h
+++ b/trunk/include/linux/pagemap.h
@@ -78,6 +78,8 @@ extern struct page * find_or_create_page(struct address_space *mapping,
 				unsigned long index, gfp_t gfp_mask);
 unsigned find_get_pages(struct address_space *mapping, pgoff_t start,
 			unsigned int nr_pages, struct page **pages);
+unsigned find_get_pages_contig(struct address_space *mapping, pgoff_t start,
+			       unsigned int nr_pages, struct page **pages);
 unsigned find_get_pages_tag(struct address_space *mapping, pgoff_t *index,
 			int tag, unsigned int nr_pages, struct page **pages);
 
diff --git a/trunk/mm/filemap.c b/trunk/mm/filemap.c
index 3ef20739e725..fd57442186cb 100644
--- a/trunk/mm/filemap.c
+++ b/trunk/mm/filemap.c
@@ -697,6 +697,38 @@ unsigned find_get_pages(struct address_space *mapping, pgoff_t start,
 	return ret;
 }
 
+/**
+ * find_get_pages_contig - gang contiguous pagecache lookup
+ * @mapping:	The address_space to search
+ * @index:	The starting page index
+ * @nr_pages:	The maximum number of pages
+ * @pages:	Where the resulting pages are placed
+ *
+ * find_get_pages_contig() works exactly like find_get_pages(), except
+ * that the returned number of pages are guaranteed to be contiguous.
+ *
+ * find_get_pages_contig() returns the number of pages which were found.
+ */
+unsigned find_get_pages_contig(struct address_space *mapping, pgoff_t index,
+			       unsigned int nr_pages, struct page **pages)
+{
+	unsigned int i;
+	unsigned int ret;
+
+	read_lock_irq(&mapping->tree_lock);
+	ret = radix_tree_gang_lookup(&mapping->page_tree,
+				(void **)pages, index, nr_pages);
+	for (i = 0; i < ret; i++) {
+		if (pages[i]->mapping == NULL || pages[i]->index != index)
+			break;
+
+		page_cache_get(pages[i]);
+		index++;
+	}
+	read_unlock_irq(&mapping->tree_lock);
+	return i;
+}
+
 /*
  * Like find_get_pages, except we only return pages which are tagged with
  * `tag'.   We update *index to index the next page for the traversal.