From: Adam Litke <agl@us.ibm.com>
Date: Tue, 16 Oct 2007 08:26:25 +0000 (-0700)
Subject: hugetlb: fix dynamic pool resize failure case
X-Git-Tag: v2.6.24-rc1~1102
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=af767cbdd78f293485c294113885d95e7f1da123;p=linux-2.6

hugetlb: fix dynamic pool resize failure case

When gather_surplus_pages() fails to allocate enough huge pages to satisfy
the requested reservation, it frees what it did allocate back to the buddy
allocator.  put_page() should be called instead of update_and_free_page()
to ensure that pool counters are updated as appropriate and the page's
refcount is decremented.

Signed-off-by: Adam Litke <agl@us.ibm.com>
Acked-by: Dave Hansen <haveblue@us.ibm.com>
Cc: David Gibson <hermes@gibson.dropbear.id.au>
Cc: William Lee Irwin III <wli@holomorphy.com>
Cc: Badari Pulavarty <pbadari@us.ibm.com>
Cc: Ken Chen <kenchen@google.com>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 82efecbab9..ae2959bb59 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -302,8 +302,17 @@ free:
 		list_del(&page->lru);
 		if ((--needed) >= 0)
 			enqueue_huge_page(page);
-		else
-			update_and_free_page(page);
+		else {
+			/*
+			 * Decrement the refcount and free the page using its
+			 * destructor.  This must be done with hugetlb_lock
+			 * unlocked which is safe because free_huge_page takes
+			 * hugetlb_lock before deciding how to free the page.
+			 */
+			spin_unlock(&hugetlb_lock);
+			put_page(page);
+			spin_lock(&hugetlb_lock);
+		}
 	}
 
 	return ret;