From 8f1d26d0e59b9676587c54578f976709b625d6e9 Mon Sep 17 00:00:00 2001
From: Atsushi Kumagai <kumagai-atsushi@mxc.nes.nec.co.jp>
Date: Wed, 30 Jul 2014 16:08:39 -0700
Subject: kexec: export free_huge_page to VMCOREINFO

PG_head_mask was added into VMCOREINFO to filter huge pages in b3acc56bfe1
("kexec: save PG_head_mask in VMCOREINFO"), but makedumpfile still need
another symbol to filter *hugetlbfs* pages.

If a user hope to filter user pages, makedumpfile tries to exclude them by
checking the condition whether the page is anonymous, but hugetlbfs pages
aren't anonymous while they also be user pages.

We know it's possible to detect them in the same way as PageHuge(),
so we need the start address of free_huge_page():

    int PageHuge(struct page *page)
    {
            if (!PageCompound(page))
                    return 0;

            page = compound_head(page);
            return get_compound_page_dtor(page) == free_huge_page;
    }

For that reason, this patch changes free_huge_page() into public
to export it to VMCOREINFO.

Signed-off-by: Atsushi Kumagai <kumagai-atsushi@mxc.nes.nec.co.jp>
Acked-by: Baoquan He <bhe@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
 kernel/kexec.c | 2 ++
 1 file changed, 2 insertions(+)

(limited to 'kernel/kexec.c')

diff --git a/kernel/kexec.c b/kernel/kexec.c
index 369f41a94124..23a088fec3c0 100644
--- a/kernel/kexec.c
+++ b/kernel/kexec.c
@@ -33,6 +33,7 @@
 #include <linux/swap.h>
 #include <linux/syscore_ops.h>
 #include <linux/compiler.h>
+#include <linux/hugetlb.h>
 
 #include <asm/page.h>
 #include <asm/uaccess.h>
@@ -1619,6 +1620,7 @@ static int __init crash_save_vmcoreinfo_init(void)
 #endif
 	VMCOREINFO_NUMBER(PG_head_mask);
 	VMCOREINFO_NUMBER(PAGE_BUDDY_MAPCOUNT_VALUE);
+	VMCOREINFO_SYMBOL(free_huge_page);
 
 	arch_crash_save_vmcoreinfo();
 	update_vmcoreinfo_note();
-- 
cgit v1.2.3


From 3a1122d26c62d4e8c61ef9a0eaba6e21c0862c77 Mon Sep 17 00:00:00 2001
From: David Rientjes <rientjes@google.com>
Date: Wed, 30 Jul 2014 19:05:55 -0700
Subject: kexec: fix build error when hugetlbfs is disabled

free_huge_page() is undefined without CONFIG_HUGETLBFS and there's no
need to filter PageHuge() page is such a configuration either, so avoid
exporting the symbol to fix a build error:

   In file included from kernel/kexec.c:14:0:
   kernel/kexec.c: In function 'crash_save_vmcoreinfo_init':
   kernel/kexec.c:1623:20: error: 'free_huge_page' undeclared (first use in this function)
     VMCOREINFO_SYMBOL(free_huge_page);
                       ^

Introduced by commit 8f1d26d0e59b ("kexec: export free_huge_page to
VMCOREINFO")

Reported-by: kbuild test robot <fengguang.wu@intel.com>
Acked-by: Olof Johansson <olof@lixom.net>
Cc: Atsushi Kumagai <kumagai-atsushi@mxc.nes.nec.co.jp>
Cc: Baoquan He <bhe@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
 kernel/kexec.c | 2 ++
 1 file changed, 2 insertions(+)

(limited to 'kernel/kexec.c')

diff --git a/kernel/kexec.c b/kernel/kexec.c
index 23a088fec3c0..4b8f0c925884 100644
--- a/kernel/kexec.c
+++ b/kernel/kexec.c
@@ -1620,7 +1620,9 @@ static int __init crash_save_vmcoreinfo_init(void)
 #endif
 	VMCOREINFO_NUMBER(PG_head_mask);
 	VMCOREINFO_NUMBER(PAGE_BUDDY_MAPCOUNT_VALUE);
+#ifdef CONFIG_HUGETLBFS
 	VMCOREINFO_SYMBOL(free_huge_page);
+#endif
 
 	arch_crash_save_vmcoreinfo();
 	update_vmcoreinfo_note();
-- 
cgit v1.2.3