From: Wu Fengguang <fengguang.wu@intel.com>
Date: Tue, 16 Jun 2009 22:31:21 +0000 (-0700)
Subject: readahead: remove one unnecessary radix tree lookup
X-Git-Tag: v2.6.31-rc1~299^2~174
X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=caca7cb748571a5b39943a9b3e7081feef055e5e;p=linux.git

readahead: remove one unnecessary radix tree lookup

(hit_readahead_marker != 0) means the page at @offset is present, so we
can search for non-present page starting from @offset+1.

Reported-by: Xu Chenfeng <xcf@ustc.edu.cn>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Cc: Ying Han <yinghan@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

diff --git a/mm/readahead.c b/mm/readahead.c
index bd0f0e88b0a1..56731158309b 100644
--- a/mm/readahead.c
+++ b/mm/readahead.c
@@ -395,7 +395,7 @@ ondemand_readahead(struct address_space *mapping,
 		pgoff_t start;
 
 		rcu_read_lock();
-		start = radix_tree_next_hole(&mapping->page_tree, offset,max+1);
+		start = radix_tree_next_hole(&mapping->page_tree, offset+1,max);
 		rcu_read_unlock();
 
 		if (!start || start - offset > max)