From 9d8c5b5284e4a0167c5f7b1193692492358b8700 Mon Sep 17 00:00:00 2001
From: Heesub Shin <heesub.shin@samsung.com>
Date: Wed, 31 Jul 2013 13:53:40 -0700
Subject: mm: zbud: fix condition check on allocation size

zbud_alloc() incorrectly verifies the size of allocation limit.  It
should deny the allocation request greater than (PAGE_SIZE -
ZHDR_SIZE_ALIGNED - CHUNK_SIZE), not (PAGE_SIZE - ZHDR_SIZE_ALIGNED)
which has no remaining spaces for its buddy.  There is no point in
spending the entire zbud page storing only a single page, since we don't
have any benefits.

Signed-off-by: Heesub Shin <heesub.shin@samsung.com>
Acked-by: Seth Jennings <sjenning@linux.vnet.ibm.com>
Cc: Bob Liu <bob.liu@oracle.com>
Cc: Dongjun Shin <d.j.shin@samsung.com>
Cc: Sunae Seo <sunae.seo@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
 mm/zbud.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/zbud.c b/mm/zbud.c
index 9bb4710e3589..ad1e781284fd 100644
--- a/mm/zbud.c
+++ b/mm/zbud.c
@@ -257,7 +257,7 @@ int zbud_alloc(struct zbud_pool *pool, int size, gfp_t gfp,
 
 	if (size <= 0 || gfp & __GFP_HIGHMEM)
 		return -EINVAL;
-	if (size > PAGE_SIZE - ZHDR_SIZE_ALIGNED)
+	if (size > PAGE_SIZE - ZHDR_SIZE_ALIGNED - CHUNK_SIZE)
 		return -ENOSPC;
 	chunks = size_to_chunks(size);
 	spin_lock(&pool->lock);
-- 
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