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[PATCH 0/3] fix allmodconfig failure of avr32

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  [PATCH 0/3] fix allmodconfig failure of avr32 Sudip Mukherjee <sudipm.mukherjee@gmail.com> - 2015-09-19 19:20 +0200
    [PATCH 3/3] page-flags: rectify forward declaration Sudip Mukherjee <sudipm.mukherjee@gmail.com> - 2015-09-19 19:20 +0200
      Re: [PATCH 3/3] page-flags: rectify forward declaration Andrew Morton <akpm@linux-foundation.org> - 2015-09-22 00:40 +0200
        Re: [PATCH 3/3] page-flags: rectify forward declaration Sudip Mukherjee <sudipm.mukherjee@gmail.com> - 2015-09-22 11:00 +0200
          Re: [PATCH 3/3] page-flags: rectify forward declaration Sudip Mukherjee <sudipm.mukherjee@gmail.com> - 2015-09-24 17:30 +0200
        [PATCH 14/16] page-flags: define PG_uptodate behavior on compound pages "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2015-09-24 17:00 +0200
        [PATCH 11/16] page-flags: define PG_swapcache behavior on compound pages "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2015-09-24 17:00 +0200
        [PATCH 02/16] page-flags: move code around "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2015-09-24 17:00 +0200
        [PATCH 05/16] page-flags: define behavior of FS/IO-related flags on compound pages "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2015-09-24 17:00 +0200
        [PATCH 01/16] page-flags: trivial cleanup for PageTrans* helpers "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2015-09-24 17:00 +0200
          Re: [PATCH 01/16] page-flags: trivial cleanup for PageTrans*  helpers Christoph Lameter <cl@linux.com> - 2015-09-24 17:50 +0200
        [PATCH 09/16] page-flags: define PG_reserved behavior on compound pages "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2015-09-24 17:00 +0200
        [PATCH 06/16] page-flags: define behavior of LRU-related flags on compound pages "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2015-09-24 17:00 +0200
        [PATCH 13/16] page-flags: define PG_uncached behavior on compound pages "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2015-09-24 17:00 +0200
        [PATCH 10/16] page-flags: define PG_swapbacked behavior on compound pages "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2015-09-24 17:00 +0200
        [PATCH 15/16] page-flags: look at head page if the flag is encoded in page->mapping "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2015-09-24 17:00 +0200
        [PATCH 08/16] page-flags: define behavior of Xen-related flags on compound pages "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2015-09-24 17:00 +0200
        [PATCH 16/16] mm: sanitize page->mapping for tail pages "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2015-09-24 17:00 +0200
          Re: [PATCH 16/16] mm: sanitize page->mapping for tail pages Jerome Glisse <j.glisse@gmail.com> - 2015-09-25 04:30 +0200
        [PATCH 07/16] page-flags: define behavior SL*B-related flags on compound pages "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2015-09-24 17:00 +0200
        [PATCH 00/16] Refreshed page-flags patchset "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2015-09-24 17:00 +0200
          [PATCH 12/16] page-flags: define PG_mlocked behavior on compound pages "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2015-09-24 17:00 +0200
          [PATCH 03/16] page-flags: introduce page flags policies wrt compound pages "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2015-09-24 17:00 +0200
            Re: [PATCH 03/16] page-flags: introduce page flags policies wrt  compound pages Konstantin Khlebnikov <khlebnikov@yandex-team.ru> - 2015-09-25 14:30 +0200
              Re: [PATCH 03/16] page-flags: introduce page flags policies wrt  compound pages "Kirill A. Shutemov" <kirill@shutemov.name> - 2015-09-25 21:20 +0200
                Re: [PATCH 03/16] page-flags: introduce page flags policies wrt  compound pages "Kirill A. Shutemov" <kirill@shutemov.name> - 2015-09-28 13:10 +0200
                  Re: [PATCH 03/16] page-flags: introduce page flags policies wrt  compound pages Konstantin Khlebnikov <khlebnikov@yandex-team.ru> - 2015-09-28 13:50 +0200
                    Re: [PATCH 03/16] page-flags: introduce page flags policies wrt  compound pages "Kirill A. Shutemov" <kirill@shutemov.name> - 2015-09-28 20:00 +0200
          [PATCH 04/16] page-flags: define PG_locked behavior on compound pages "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2015-09-24 17:00 +0200
            Re: [PATCH 04/16] page-flags: define PG_locked behavior on compound  pages Christoph Lameter <cl@linux.com> - 2015-09-24 18:10 +0200
              Re: [PATCH 04/16] page-flags: define PG_locked behavior on compound  pages "Kirill A. Shutemov" <kirill@shutemov.name> - 2015-09-24 22:30 +0200
          Re: [PATCH 00/16] Refreshed page-flags patchset Christoph Lameter <cl@linux.com> - 2015-09-24 18:20 +0200
            Re: [PATCH 00/16] Refreshed page-flags patchset "Kirill A. Shutemov" <kirill@shutemov.name> - 2015-09-24 22:30 +0200

Page 1 of 2  [1] 2  Next page →

#1228479 — [PATCH 0/3] fix allmodconfig failure of avr32

Build of allmodconfig with avr32 used to fail with the errors:
error: implicit declaration of function 'pci_iomap'
error: implicit declaration of function 'pci_iounmap'
and
"at91_pmc_base" [drivers/usb/gadget/udc/atmel_usba_udc.ko] undefined!

First two patches fixes these two problems. Third patch is related to a
build warning:
warning: 'compound_head' declared inline after being called.
warning: previous declaration of 'compound_head' was here.

regards
sudip

Sudip Mukherjee (3):
  avr32: fix build failure
  usb: gadget: at91_udc: mention proper dependency
  page-flags: rectify forward declaration

 arch/avr32/include/asm/io.h    | 13 +++++++++++++
 drivers/usb/gadget/udc/Kconfig |  2 +-
 include/linux/page-flags.h     |  2 +-
 3 files changed, 15 insertions(+), 2 deletions(-)

-- 
1.9.1

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#1228481 — [PATCH 3/3] page-flags: rectify forward declaration

compound_head is defined as inline in page-flags.h but in the forward
declaration of compound_head in the same file missed "inline". As a result
we got plenty of build warnings while building for some architecture
like avr32. The warning showed as:
warning: 'compound_head' declared inline after being called.
warning: previous declaration of 'compound_head' was here

Signed-off-by: Sudip Mukherjee <sudip@vectorindia.org>
---

tested build with avr32 and also with x86_64 allmodconfig to verify that
nothing breaks due to this change.

 include/linux/page-flags.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index ab1a0e9..2a2391c 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -227,7 +227,7 @@ static inline int __TestClearPage##uname(struct page *page) { return 0; }
 struct page;
 static inline int PageCompound(struct page *page);
 static inline int PageTail(struct page *page);
-static struct page *compound_head(struct page *page);
+static inline struct page *compound_head(struct page *page);
 
 __PAGEFLAG(Locked, locked, PF_NO_TAIL)
 PAGEFLAG(Error, error, PF_NO_COMPOUND) TESTCLEARFLAG(Error, error, PF_NO_COMPOUND)
-- 
1.9.1

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#1229798 — Re: [PATCH 3/3] page-flags: rectify forward declaration

On Sat, 19 Sep 2015 22:42:59 +0530 Sudip Mukherjee <sudipm.mukherjee@gmail.com> wrote:

> compound_head is defined as inline in page-flags.h but in the forward
> declaration of compound_head in the same file missed "inline". As a result
> we got plenty of build warnings while building for some architecture
> like avr32. The warning showed as:
> warning: 'compound_head' declared inline after being called.
> warning: previous declaration of 'compound_head' was here
> 
> ...
>
> --- a/include/linux/page-flags.h
> +++ b/include/linux/page-flags.h
> @@ -227,7 +227,7 @@ static inline int __TestClearPage##uname(struct page *page) { return 0; }
>  struct page;
>  static inline int PageCompound(struct page *page);
>  static inline int PageTail(struct page *page);
> -static struct page *compound_head(struct page *page);
> +static inline struct page *compound_head(struct page *page);
>  
>  __PAGEFLAG(Locked, locked, PF_NO_TAIL)
>  PAGEFLAG(Error, error, PF_NO_COMPOUND) TESTCLEARFLAG(Error, error, PF_NO_COMPOUND)

Yes, that's an error, in -mm due to Kirill's page-flags patches.


The code is effectively doing

static inline XXX foo(...);

static inline YYY bar(...)
{
	foo(...);
}

inline XXX foo(...)
{
	...
}

ie: asking gcc to inline a forward-defined function.  That does work,
but it's unusual and unexpected, and it's a bit unwise to expect the
compiler to do unusual and more difficult things.

Is it fixable?  Can we use the traditional define-before-using structure?

Also, I'm finding that the patch series introduces a pretty large
bisection hole:

include/linux/page-flags.h: In function 'PageYoung':
include/linux/page-flags.h:327: error: implicit declaration of function 'PF_ANY'
include/linux/page-flags.h:327: error: invalid type argument of '->' (have 'int')
include/linux/page-flags.h:327: error: invalid type argument of '->' (have 'int')

which later gets fixed up by
page-flags-rectify-forward-declaration.patch.

Maybe it's time to do a wholesale refactoring of the patchset?
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#1229988 — Re: [PATCH 3/3] page-flags: rectify forward declaration

On Mon, Sep 21, 2015 at 03:35:09PM -0700, Andrew Morton wrote:
> On Sat, 19 Sep 2015 22:42:59 +0530 Sudip Mukherjee <sudipm.mukherjee@gmail.com> wrote:
> 
<snip>
> 
> Is it fixable?  Can we use the traditional define-before-using structure?
How about this:

diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index ab1a0e9..d7a1055 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -133,6 +133,19 @@ enum pageflags {
 
 #ifndef __GENERATING_BOUNDS_H
 
+/* Forward declarations */
+struct page;
+static inline int PageCompound(struct page *page);
+static inline int PageTail(struct page *page);
+static inline struct page *compound_head(struct page *page)
+{
+	unsigned long head = READ_ONCE(page->compound_head);
+
+	if (unlikely(head & 1))
+		return (struct page *) (head - 1);
+	return page;
+}
+
 /* Page flags policies wrt compound pages */
 #define PF_ANY(page, enforce)	page
 #define PF_HEAD(page, enforce)	compound_head(page)
@@ -223,12 +236,6 @@ static inline int __TestClearPage##uname(struct page *page) { return 0; }
 #define TESTSCFLAG_FALSE(uname)						\
 	TESTSETFLAG_FALSE(uname) TESTCLEARFLAG_FALSE(uname)
 
-/* Forward declarations */
-struct page;
-static inline int PageCompound(struct page *page);
-static inline int PageTail(struct page *page);
-static struct page *compound_head(struct page *page);
-
 __PAGEFLAG(Locked, locked, PF_NO_TAIL)
 PAGEFLAG(Error, error, PF_NO_COMPOUND) TESTCLEARFLAG(Error, error, PF_NO_COMPOUND)
 PAGEFLAG(Referenced, referenced, PF_HEAD)
@@ -450,15 +457,6 @@ static inline void clear_compound_head(struct page *page)
 	WRITE_ONCE(page->compound_head, 0);
 }
 
-static inline struct page *compound_head(struct page *page)
-{
-	unsigned long head = READ_ONCE(page->compound_head);
-
-	if (unlikely(head & 1))
-		return (struct page *) (head - 1);
-	return page;
-}
-
 static inline int PageCompound(struct page *page)
 {
 	return PageHead(page) || PageTail(page);


---
It builds properly. Tested with allmodconfig of x86_64 and avr32.

> 
> Also, I'm finding that the patch series introduces a pretty large
> bisection hole:
> 
> include/linux/page-flags.h: In function 'PageYoung':
> include/linux/page-flags.h:327: error: implicit declaration of function 'PF_ANY'
> include/linux/page-flags.h:327: error: invalid type argument of '->' (have 'int')
> include/linux/page-flags.h:327: error: invalid type argument of '->' (have 'int')
> 
> which later gets fixed up by
> page-flags-rectify-forward-declaration.patch.
How to test this? Should I apply them on top of v4.2 and bisect? And I
don't see any relation between the first two patches and this patch of
the series, then how does it fail in bisect? Am I missing something?
Confused.. :(
> 
> Maybe it's time to do a wholesale refactoring of the patchset?
If this patch is the first in the series will that help?
And besides I got the auto mail from you that the patch is applied.
Now totally confused.. :(

regards
sudip
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#1232190 — Re: [PATCH 3/3] page-flags: rectify forward declaration

> > 
> > Also, I'm finding that the patch series introduces a pretty large
> > bisection hole:
> > 
> > include/linux/page-flags.h: In function 'PageYoung':
> > include/linux/page-flags.h:327: error: implicit declaration of function 'PF_ANY'
> > include/linux/page-flags.h:327: error: invalid type argument of '->' (have 'int')
> > include/linux/page-flags.h:327: error: invalid type argument of '->' (have 'int')
> > 
> > which later gets fixed up by
> > page-flags-rectify-forward-declaration.patch.
> How to test this? Should I apply them on top of v4.2 and bisect? And I
> don't see any relation between the first two patches and this patch of
> the series, then how does it fail in bisect? Am I missing something?
> Confused.. :(
> > 
> > Maybe it's time to do a wholesale refactoring of the patchset?
> If this patch is the first in the series will that help?
> And besides I got the auto mail from you that the patch is applied.
> Now totally confused.. :(
Ohhh ..all the time you were talking about Kirill's patch set and I kept
thinking you are mentioning about this patchset. :)

regards
sudip
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#1232142 — [PATCH 14/16] page-flags: define PG_uptodate behavior on compound pages

We use PG_uptodate on head pages on transparent huge page.
Let's use PF_NO_TAIL.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
 include/linux/page-flags.h | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index 5e52cc6a27c3..e3ccd95de660 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -392,8 +392,9 @@ u64 stable_page_flags(struct page *page);
 
 static inline int PageUptodate(struct page *page)
 {
-	int ret = test_bit(PG_uptodate, &(page)->flags);
-
+	int ret;
+	page = compound_head(page);
+	ret = test_bit(PG_uptodate, &(page)->flags);
 	/*
 	 * Must ensure that the data we read out of the page is loaded
 	 * _after_ we've loaded page->flags to check for PageUptodate.
@@ -410,12 +411,14 @@ static inline int PageUptodate(struct page *page)
 
 static inline void __SetPageUptodate(struct page *page)
 {
+	VM_BUG_ON_PAGE(PageTail(page), page);
 	smp_wmb();
 	__set_bit(PG_uptodate, &page->flags);
 }
 
 static inline void SetPageUptodate(struct page *page)
 {
+	VM_BUG_ON_PAGE(PageTail(page), page);
 	/*
 	 * Memory barrier must be issued before setting the PG_uptodate bit,
 	 * so that all previous stores issued in order to bring the page
@@ -425,7 +428,7 @@ static inline void SetPageUptodate(struct page *page)
 	set_bit(PG_uptodate, &page->flags);
 }
 
-CLEARPAGEFLAG(Uptodate, uptodate, PF_ANY)
+CLEARPAGEFLAG(Uptodate, uptodate, PF_NO_TAIL)
 
 int test_clear_page_writeback(struct page *page);
 int __test_set_page_writeback(struct page *page, bool keep_write);
-- 
2.5.1

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#1232144 — [PATCH 11/16] page-flags: define PG_swapcache behavior on compound pages

Swap cannot handle compound pages so far. Transparent huge pages are
split on the way to swap.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
 include/linux/page-flags.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index a31d682caeb2..c933416b2f92 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -306,7 +306,7 @@ PAGEFLAG_FALSE(HighMem)
 #endif
 
 #ifdef CONFIG_SWAP
-PAGEFLAG(SwapCache, swapcache, PF_ANY)
+PAGEFLAG(SwapCache, swapcache, PF_NO_COMPOUND)
 #else
 PAGEFLAG_FALSE(SwapCache)
 #endif
-- 
2.5.1

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#1232145 — [PATCH 02/16] page-flags: move code around

The preparation patch: we are going to use compound_head(), PageTail()
and PageCompound() to define page-flags helpers.

Let's define them before macros.

We cannot user PageHead() helper in PageCompound() as it's not yet
defined -- use test_bit(PG_head, &page->flags) instead.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
 include/linux/page-flags.h | 41 +++++++++++++++++++++--------------------
 1 file changed, 21 insertions(+), 20 deletions(-)

diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index 815246a80e2d..713d3f2c2468 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -133,6 +133,27 @@ enum pageflags {
 
 #ifndef __GENERATING_BOUNDS_H
 
+struct page;	/* forward declaration */
+
+static inline struct page *compound_head(struct page *page)
+{
+	unsigned long head = READ_ONCE(page->compound_head);
+
+	if (unlikely(head & 1))
+		return (struct page *) (head - 1);
+	return page;
+}
+
+static inline int PageTail(struct page *page)
+{
+	return READ_ONCE(page->compound_head) & 1;
+}
+
+static inline int PageCompound(struct page *page)
+{
+	return test_bit(PG_head, &page->flags) || PageTail(page);
+}
+
 /*
  * Macros to create function definitions for page flags
  */
@@ -204,7 +225,6 @@ static inline int __TestClearPage##uname(struct page *page) { return 0; }
 #define TESTSCFLAG_FALSE(uname)						\
 	TESTSETFLAG_FALSE(uname) TESTCLEARFLAG_FALSE(uname)
 
-struct page;	/* forward declaration */
 
 TESTPAGEFLAG(Locked, locked)
 PAGEFLAG(Error, error) TESTCLEARFLAG(Error, error)
@@ -395,11 +415,6 @@ static inline void set_page_writeback_keepwrite(struct page *page)
 
 __PAGEFLAG(Head, head) CLEARPAGEFLAG(Head, head)
 
-static inline int PageTail(struct page *page)
-{
-	return READ_ONCE(page->compound_head) & 1;
-}
-
 static inline void set_compound_head(struct page *page, struct page *head)
 {
 	WRITE_ONCE(page->compound_head, (unsigned long)head + 1);
@@ -410,20 +425,6 @@ static inline void clear_compound_head(struct page *page)
 	WRITE_ONCE(page->compound_head, 0);
 }
 
-static inline struct page *compound_head(struct page *page)
-{
-	unsigned long head = READ_ONCE(page->compound_head);
-
-	if (unlikely(head & 1))
-		return (struct page *) (head - 1);
-	return page;
-}
-
-static inline int PageCompound(struct page *page)
-{
-	return PageHead(page) || PageTail(page);
-
-}
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 static inline void ClearPageCompound(struct page *page)
 {
-- 
2.5.1

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#1232146 — [PATCH 05/16] page-flags: define behavior of FS/IO-related flags on compound pages

It seems we don't have compound page on FS/IO path currently.
Use PF_NO_COMPOUND to catch if we have.

The odd exception is PG_dirty: sound uses compound pages and maps them
with PTEs. PF_NO_COMPOUND triggers VM_BUG_ON() in set_page_dirty() on
handling shared fault.  Let's use PF_HEAD for PG_dirty.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
 include/linux/page-flags.h | 23 +++++++++++++----------
 1 file changed, 13 insertions(+), 10 deletions(-)

diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index 26102813f0ac..63db7483c264 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -245,16 +245,16 @@ static inline int __TestClearPage##uname(struct page *page) { return 0; }
 	TESTSETFLAG_FALSE(uname) TESTCLEARFLAG_FALSE(uname)
 
 __PAGEFLAG(Locked, locked, PF_NO_TAIL)
-PAGEFLAG(Error, error, PF_ANY) TESTCLEARFLAG(Error, error, PF_ANY)
+PAGEFLAG(Error, error, PF_NO_COMPOUND) TESTCLEARFLAG(Error, error, PF_NO_COMPOUND)
 PAGEFLAG(Referenced, referenced, PF_ANY) TESTCLEARFLAG(Referenced, referenced, PF_ANY)
 	__SETPAGEFLAG(Referenced, referenced, PF_ANY)
-PAGEFLAG(Dirty, dirty, PF_ANY) TESTSCFLAG(Dirty, dirty, PF_ANY)
-	__CLEARPAGEFLAG(Dirty, dirty, PF_ANY)
+PAGEFLAG(Dirty, dirty, PF_HEAD) TESTSCFLAG(Dirty, dirty, PF_HEAD)
+	__CLEARPAGEFLAG(Dirty, dirty, PF_HEAD)
 PAGEFLAG(LRU, lru, PF_ANY) __CLEARPAGEFLAG(LRU, lru, PF_ANY)
 PAGEFLAG(Active, active, PF_ANY) __CLEARPAGEFLAG(Active, active, PF_ANY)
 	TESTCLEARFLAG(Active, active, PF_ANY)
 __PAGEFLAG(Slab, slab, PF_ANY)
-PAGEFLAG(Checked, checked, PF_ANY)		/* Used by some filesystems */
+PAGEFLAG(Checked, checked, PF_NO_COMPOUND)	   /* Used by some filesystems */
 PAGEFLAG(Pinned, pinned, PF_ANY) TESTSCFLAG(Pinned, pinned, PF_ANY)	/* Xen */
 PAGEFLAG(SavePinned, savepinned, PF_ANY);			/* Xen */
 PAGEFLAG(Foreign, foreign, PF_ANY);				/* Xen */
@@ -280,12 +280,15 @@ PAGEFLAG(OwnerPriv1, owner_priv_1, PF_ANY)
  * Only test-and-set exist for PG_writeback.  The unconditional operators are
  * risky: they bypass page accounting.
  */
-TESTPAGEFLAG(Writeback, writeback, PF_ANY) TESTSCFLAG(Writeback, writeback, PF_ANY)
-PAGEFLAG(MappedToDisk, mappedtodisk, PF_ANY)
+TESTPAGEFLAG(Writeback, writeback, PF_NO_COMPOUND)
+	TESTSCFLAG(Writeback, writeback, PF_NO_COMPOUND)
+PAGEFLAG(MappedToDisk, mappedtodisk, PF_NO_COMPOUND)
 
 /* PG_readahead is only used for reads; PG_reclaim is only for writes */
-PAGEFLAG(Reclaim, reclaim, PF_ANY) TESTCLEARFLAG(Reclaim, reclaim, PF_ANY)
-PAGEFLAG(Readahead, reclaim, PF_ANY) TESTCLEARFLAG(Readahead, reclaim, PF_ANY)
+PAGEFLAG(Reclaim, reclaim, PF_NO_COMPOUND)
+	TESTCLEARFLAG(Reclaim, reclaim, PF_NO_COMPOUND)
+PAGEFLAG(Readahead, reclaim, PF_NO_COMPOUND)
+	TESTCLEARFLAG(Readahead, reclaim, PF_NO_COMPOUND)
 
 #ifdef CONFIG_HIGHMEM
 /*
@@ -401,7 +404,7 @@ static inline int PageUptodate(struct page *page)
 static inline void __SetPageUptodate(struct page *page)
 {
 	smp_wmb();
-	__set_bit(PG_uptodate, &(page)->flags);
+	__set_bit(PG_uptodate, &page->flags);
 }
 
 static inline void SetPageUptodate(struct page *page)
@@ -412,7 +415,7 @@ static inline void SetPageUptodate(struct page *page)
 	 * uptodate are actually visible before PageUptodate becomes true.
 	 */
 	smp_wmb();
-	set_bit(PG_uptodate, &(page)->flags);
+	set_bit(PG_uptodate, &page->flags);
 }
 
 CLEARPAGEFLAG(Uptodate, uptodate, PF_ANY)
-- 
2.5.1

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#1232148 — [PATCH 01/16] page-flags: trivial cleanup for PageTrans* helpers

Use TESTPAGEFLAG_FALSE() to get it a bit cleaner.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
 include/linux/page-flags.h | 18 +++---------------
 1 file changed, 3 insertions(+), 15 deletions(-)

diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index 4fdfb5ed4b43..815246a80e2d 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -485,21 +485,9 @@ static inline int PageTransTail(struct page *page)
 }
 
 #else
-
-static inline int PageTransHuge(struct page *page)
-{
-	return 0;
-}
-
-static inline int PageTransCompound(struct page *page)
-{
-	return 0;
-}
-
-static inline int PageTransTail(struct page *page)
-{
-	return 0;
-}
+TESTPAGEFLAG_FALSE(TransHuge)
+TESTPAGEFLAG_FALSE(TransCompound)
+TESTPAGEFLAG_FALSE(TransTail)
 #endif
 
 /*
-- 
2.5.1

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#1232213 — Re: [PATCH 01/16] page-flags: trivial cleanup for PageTrans* helpers

On Thu, 24 Sep 2015, Kirill A. Shutemov wrote:

> Use TESTPAGEFLAG_FALSE() to get it a bit cleaner.

Acked-by: Christoph Lameter <cl@linux.com>
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#1232153 — [PATCH 09/16] page-flags: define PG_reserved behavior on compound pages

As far as I can see there's no users of PG_reserved on compound pages.
Let's use PF_NO_COMPOUND here.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
 include/linux/page-flags.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index adaa2b39f471..5ba8130fffb5 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -264,7 +264,8 @@ PAGEFLAG(Pinned, pinned, PF_NO_COMPOUND)
 PAGEFLAG(SavePinned, savepinned, PF_NO_COMPOUND);
 PAGEFLAG(Foreign, foreign, PF_NO_COMPOUND);
 
-PAGEFLAG(Reserved, reserved, PF_ANY) __CLEARPAGEFLAG(Reserved, reserved, PF_ANY)
+PAGEFLAG(Reserved, reserved, PF_NO_COMPOUND)
+	__CLEARPAGEFLAG(Reserved, reserved, PF_NO_COMPOUND)
 PAGEFLAG(SwapBacked, swapbacked, PF_ANY)
 	__CLEARPAGEFLAG(SwapBacked, swapbacked, PF_ANY)
 	__SETPAGEFLAG(SwapBacked, swapbacked, PF_ANY)
-- 
2.5.1

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#1232155 — [PATCH 06/16] page-flags: define behavior of LRU-related flags on compound pages

Only head pages are ever on LRU. Let's use PF_HEAD policy to avoid any
confusion for all LRU-related flags.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
 include/linux/page-flags.h | 17 +++++++++--------
 1 file changed, 9 insertions(+), 8 deletions(-)

diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index 63db7483c264..10b75615ddf2 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -246,13 +246,14 @@ static inline int __TestClearPage##uname(struct page *page) { return 0; }
 
 __PAGEFLAG(Locked, locked, PF_NO_TAIL)
 PAGEFLAG(Error, error, PF_NO_COMPOUND) TESTCLEARFLAG(Error, error, PF_NO_COMPOUND)
-PAGEFLAG(Referenced, referenced, PF_ANY) TESTCLEARFLAG(Referenced, referenced, PF_ANY)
-	__SETPAGEFLAG(Referenced, referenced, PF_ANY)
+PAGEFLAG(Referenced, referenced, PF_HEAD)
+	TESTCLEARFLAG(Referenced, referenced, PF_HEAD)
+	__SETPAGEFLAG(Referenced, referenced, PF_HEAD)
 PAGEFLAG(Dirty, dirty, PF_HEAD) TESTSCFLAG(Dirty, dirty, PF_HEAD)
 	__CLEARPAGEFLAG(Dirty, dirty, PF_HEAD)
-PAGEFLAG(LRU, lru, PF_ANY) __CLEARPAGEFLAG(LRU, lru, PF_ANY)
-PAGEFLAG(Active, active, PF_ANY) __CLEARPAGEFLAG(Active, active, PF_ANY)
-	TESTCLEARFLAG(Active, active, PF_ANY)
+PAGEFLAG(LRU, lru, PF_HEAD) __CLEARPAGEFLAG(LRU, lru, PF_HEAD)
+PAGEFLAG(Active, active, PF_HEAD) __CLEARPAGEFLAG(Active, active, PF_HEAD)
+	TESTCLEARFLAG(Active, active, PF_HEAD)
 __PAGEFLAG(Slab, slab, PF_ANY)
 PAGEFLAG(Checked, checked, PF_NO_COMPOUND)	   /* Used by some filesystems */
 PAGEFLAG(Pinned, pinned, PF_ANY) TESTSCFLAG(Pinned, pinned, PF_ANY)	/* Xen */
@@ -306,9 +307,9 @@ PAGEFLAG(SwapCache, swapcache, PF_ANY)
 PAGEFLAG_FALSE(SwapCache)
 #endif
 
-PAGEFLAG(Unevictable, unevictable, PF_ANY)
-	__CLEARPAGEFLAG(Unevictable, unevictable, PF_ANY)
-	TESTCLEARFLAG(Unevictable, unevictable, PF_ANY)
+PAGEFLAG(Unevictable, unevictable, PF_HEAD)
+	__CLEARPAGEFLAG(Unevictable, unevictable, PF_HEAD)
+	TESTCLEARFLAG(Unevictable, unevictable, PF_HEAD)
 
 #ifdef CONFIG_MMU
 PAGEFLAG(Mlocked, mlocked, PF_ANY) __CLEARPAGEFLAG(Mlocked, mlocked, PF_ANY)
-- 
2.5.1

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#1232156 — [PATCH 13/16] page-flags: define PG_uncached behavior on compound pages

So far, only IA64 uses PG_uncached and only on non-compound pages.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
 include/linux/page-flags.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index 31e68a8c2777..5e52cc6a27c3 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -326,7 +326,7 @@ PAGEFLAG_FALSE(Mlocked) __CLEARPAGEFLAG_NOOP(Mlocked)
 #endif
 
 #ifdef CONFIG_ARCH_USES_PG_UNCACHED
-PAGEFLAG(Uncached, uncached, PF_ANY)
+PAGEFLAG(Uncached, uncached, PF_NO_COMPOUND)
 #else
 PAGEFLAG_FALSE(Uncached)
 #endif
-- 
2.5.1

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#1232157 — [PATCH 10/16] page-flags: define PG_swapbacked behavior on compound pages

PG_swapbacked is used for transparent huge pages. For head pages only.
Let's use PF_NO_TAIL policy.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
 include/linux/page-flags.h | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index 5ba8130fffb5..a31d682caeb2 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -266,9 +266,9 @@ PAGEFLAG(Foreign, foreign, PF_NO_COMPOUND);
 
 PAGEFLAG(Reserved, reserved, PF_NO_COMPOUND)
 	__CLEARPAGEFLAG(Reserved, reserved, PF_NO_COMPOUND)
-PAGEFLAG(SwapBacked, swapbacked, PF_ANY)
-	__CLEARPAGEFLAG(SwapBacked, swapbacked, PF_ANY)
-	__SETPAGEFLAG(SwapBacked, swapbacked, PF_ANY)
+PAGEFLAG(SwapBacked, swapbacked, PF_NO_TAIL)
+	__CLEARPAGEFLAG(SwapBacked, swapbacked, PF_NO_TAIL)
+	__SETPAGEFLAG(SwapBacked, swapbacked, PF_NO_TAIL)
 
 /*
  * Private page markings that may be used by the filesystem that owns the page
-- 
2.5.1

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#1232158 — [PATCH 15/16] page-flags: look at head page if the flag is encoded in page->mapping

PageAnon() and PageKsm() look at lower bits of page->mapping to check if
the page is Anon or KSM.  page->mapping can be overloaded in tail pages.

Let's always look at head page to avoid false-positives.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
 include/linux/page-flags.h | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index e3ccd95de660..6f5df65d1038 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -369,6 +369,7 @@ PAGEFLAG(Idle, idle, PF_ANY)
 
 static inline int PageAnon(struct page *page)
 {
+	page = compound_head(page);
 	return ((unsigned long)page->mapping & PAGE_MAPPING_ANON) != 0;
 }
 
@@ -381,6 +382,7 @@ static inline int PageAnon(struct page *page)
  */
 static inline int PageKsm(struct page *page)
 {
+	page = compound_head(page);
 	return ((unsigned long)page->mapping & PAGE_MAPPING_FLAGS) ==
 				(PAGE_MAPPING_ANON | PAGE_MAPPING_KSM);
 }
-- 
2.5.1

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#1232159 — [PATCH 08/16] page-flags: define behavior of Xen-related flags on compound pages

PG_pinned and PG_savepinned are about page table's pages which are never
compound.

I'm not so sure about PG_foreign, but it seems we shouldn't see compound
pages there too.

Let's use PF_NO_COMPOUND for all of them.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
 include/linux/page-flags.h | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index c9cd82310e2d..adaa2b39f471 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -257,9 +257,13 @@ PAGEFLAG(Active, active, PF_HEAD) __CLEARPAGEFLAG(Active, active, PF_HEAD)
 __PAGEFLAG(Slab, slab, PF_NO_TAIL)
 __PAGEFLAG(SlobFree, slob_free, PF_NO_TAIL)
 PAGEFLAG(Checked, checked, PF_NO_COMPOUND)	   /* Used by some filesystems */
-PAGEFLAG(Pinned, pinned, PF_ANY) TESTSCFLAG(Pinned, pinned, PF_ANY)	/* Xen */
-PAGEFLAG(SavePinned, savepinned, PF_ANY);			/* Xen */
-PAGEFLAG(Foreign, foreign, PF_ANY);				/* Xen */
+
+/* Xen */
+PAGEFLAG(Pinned, pinned, PF_NO_COMPOUND)
+	TESTSCFLAG(Pinned, pinned, PF_NO_COMPOUND)
+PAGEFLAG(SavePinned, savepinned, PF_NO_COMPOUND);
+PAGEFLAG(Foreign, foreign, PF_NO_COMPOUND);
+
 PAGEFLAG(Reserved, reserved, PF_ANY) __CLEARPAGEFLAG(Reserved, reserved, PF_ANY)
 PAGEFLAG(SwapBacked, swapbacked, PF_ANY)
 	__CLEARPAGEFLAG(SwapBacked, swapbacked, PF_ANY)
-- 
2.5.1

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#1232160 — [PATCH 16/16] mm: sanitize page->mapping for tail pages

We don't define meaning of page->mapping for tail pages.  Currently it's
always NULL, which can be inconsistent with head page and potentially lead
to problems.

Let's poison the pointer to catch all illigal uses.

page_rmapping(), page_mapping() and page_anon_vma() are changed to look on
head page.

The only illegal use I've caught so far is __GPF_COMP pages from sound
subsystem, mapped with PTEs.  do_shared_fault() is changed to use
page_rmapping() instead of direct access to fault_page->mapping.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
 include/linux/poison.h |  4 ++++
 mm/huge_memory.c       |  2 +-
 mm/memory.c            |  2 +-
 mm/page_alloc.c        |  6 ++++++
 mm/util.c              | 10 ++++++----
 5 files changed, 18 insertions(+), 6 deletions(-)

diff --git a/include/linux/poison.h b/include/linux/poison.h
index 317e16de09e5..76c3b6c38c16 100644
--- a/include/linux/poison.h
+++ b/include/linux/poison.h
@@ -32,6 +32,10 @@
 /********** mm/debug-pagealloc.c **********/
 #define PAGE_POISON 0xaa
 
+/********** mm/page_alloc.c ************/
+
+#define TAIL_MAPPING	((void *) 0x01014A11 + POISON_POINTER_DELTA)
+
 /********** mm/slab.c **********/
 /*
  * Magic nums for obj red zoning.
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 244c852d565c..65ab7858bbcc 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1836,7 +1836,7 @@ static void __split_huge_page_refcount(struct page *page,
 		*/
 		page_tail->_mapcount = page->_mapcount;
 
-		BUG_ON(page_tail->mapping);
+		BUG_ON(page_tail->mapping != TAIL_MAPPING);
 		page_tail->mapping = page->mapping;
 
 		page_tail->index = page->index + i;
diff --git a/mm/memory.c b/mm/memory.c
index caecc64301e9..3bd465a6fa0d 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -3087,7 +3087,7 @@ static int do_shared_fault(struct mm_struct *mm, struct vm_area_struct *vma,
 	 * pinned by vma->vm_file's reference.  We rely on unlock_page()'s
 	 * release semantics to prevent the compiler from undoing this copying.
 	 */
-	mapping = fault_page->mapping;
+	mapping = page_rmapping(fault_page);
 	unlock_page(fault_page);
 	if ((dirtied || vma->vm_ops->page_mkwrite) && mapping) {
 		/*
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 321a91747949..9bcfd70b1eb8 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -473,6 +473,7 @@ void prep_compound_page(struct page *page, unsigned int order)
 	for (i = 1; i < nr_pages; i++) {
 		struct page *p = page + i;
 		set_page_count(p, 0);
+		p->mapping = TAIL_MAPPING;
 		set_compound_head(p, page);
 	}
 }
@@ -864,6 +865,10 @@ static int free_tail_pages_check(struct page *head_page, struct page *page)
 		ret = 0;
 		goto out;
 	}
+	if (page->mapping != TAIL_MAPPING) {
+		bad_page(page, "corrupted mapping in tail page", 0);
+		goto out;
+	}
 	if (unlikely(!PageTail(page))) {
 		bad_page(page, "PageTail not set", 0);
 		goto out;
@@ -874,6 +879,7 @@ static int free_tail_pages_check(struct page *head_page, struct page *page)
 	}
 	ret = 0;
 out:
+	page->mapping = NULL;
 	clear_compound_head(page);
 	return ret;
 }
diff --git a/mm/util.c b/mm/util.c
index 9af1c12b310c..902b65a43899 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -355,7 +355,9 @@ struct anon_vma *page_anon_vma(struct page *page)
 
 struct address_space *page_mapping(struct page *page)
 {
-	unsigned long mapping;
+	struct address_space *mapping;
+
+	page = compound_head(page);
 
 	/* This happens if someone calls flush_dcache_page on slab page */
 	if (unlikely(PageSlab(page)))
@@ -368,10 +370,10 @@ struct address_space *page_mapping(struct page *page)
 		return swap_address_space(entry);
 	}
 
-	mapping = (unsigned long)page->mapping;
-	if (mapping & PAGE_MAPPING_FLAGS)
+	mapping = page->mapping;
+	if ((unsigned long)mapping & PAGE_MAPPING_FLAGS)
 		return NULL;
-	return page->mapping;
+	return mapping;
 }
 
 int overcommit_ratio_handler(struct ctl_table *table, int write,
-- 
2.5.1

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#1232540 — Re: [PATCH 16/16] mm: sanitize page->mapping for tail pages

On Thu, Sep 24, 2015 at 05:51:04PM +0300, Kirill A. Shutemov wrote:
> We don't define meaning of page->mapping for tail pages.  Currently it's
> always NULL, which can be inconsistent with head page and potentially lead
> to problems.
> 
> Let's poison the pointer to catch all illigal uses.
> 
> page_rmapping(), page_mapping() and page_anon_vma() are changed to look on
> head page.
> 
> The only illegal use I've caught so far is __GPF_COMP pages from sound
> subsystem, mapped with PTEs.  do_shared_fault() is changed to use
> page_rmapping() instead of direct access to fault_page->mapping.
> 
> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>


Just a nitpick but page_rmapping() is already using compound_head() and
thus commit message is missleading. I was expecting to see some changes
to page_rmapping(). Anyway:

Reviewed-by: Jérôme Glisse <jglisse@redhat.com>


> ---
>  include/linux/poison.h |  4 ++++
>  mm/huge_memory.c       |  2 +-
>  mm/memory.c            |  2 +-
>  mm/page_alloc.c        |  6 ++++++
>  mm/util.c              | 10 ++++++----
>  5 files changed, 18 insertions(+), 6 deletions(-)
> 
> diff --git a/include/linux/poison.h b/include/linux/poison.h
> index 317e16de09e5..76c3b6c38c16 100644
> --- a/include/linux/poison.h
> +++ b/include/linux/poison.h
> @@ -32,6 +32,10 @@
>  /********** mm/debug-pagealloc.c **********/
>  #define PAGE_POISON 0xaa
>  
> +/********** mm/page_alloc.c ************/
> +
> +#define TAIL_MAPPING	((void *) 0x01014A11 + POISON_POINTER_DELTA)
> +
>  /********** mm/slab.c **********/
>  /*
>   * Magic nums for obj red zoning.
> diff --git a/mm/huge_memory.c b/mm/huge_memory.c
> index 244c852d565c..65ab7858bbcc 100644
> --- a/mm/huge_memory.c
> +++ b/mm/huge_memory.c
> @@ -1836,7 +1836,7 @@ static void __split_huge_page_refcount(struct page *page,
>  		*/
>  		page_tail->_mapcount = page->_mapcount;
>  
> -		BUG_ON(page_tail->mapping);
> +		BUG_ON(page_tail->mapping != TAIL_MAPPING);
>  		page_tail->mapping = page->mapping;
>  
>  		page_tail->index = page->index + i;
> diff --git a/mm/memory.c b/mm/memory.c
> index caecc64301e9..3bd465a6fa0d 100644
> --- a/mm/memory.c
> +++ b/mm/memory.c
> @@ -3087,7 +3087,7 @@ static int do_shared_fault(struct mm_struct *mm, struct vm_area_struct *vma,
>  	 * pinned by vma->vm_file's reference.  We rely on unlock_page()'s
>  	 * release semantics to prevent the compiler from undoing this copying.
>  	 */
> -	mapping = fault_page->mapping;
> +	mapping = page_rmapping(fault_page);
>  	unlock_page(fault_page);
>  	if ((dirtied || vma->vm_ops->page_mkwrite) && mapping) {
>  		/*
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index 321a91747949..9bcfd70b1eb8 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -473,6 +473,7 @@ void prep_compound_page(struct page *page, unsigned int order)
>  	for (i = 1; i < nr_pages; i++) {
>  		struct page *p = page + i;
>  		set_page_count(p, 0);
> +		p->mapping = TAIL_MAPPING;
>  		set_compound_head(p, page);
>  	}
>  }
> @@ -864,6 +865,10 @@ static int free_tail_pages_check(struct page *head_page, struct page *page)
>  		ret = 0;
>  		goto out;
>  	}
> +	if (page->mapping != TAIL_MAPPING) {
> +		bad_page(page, "corrupted mapping in tail page", 0);
> +		goto out;
> +	}
>  	if (unlikely(!PageTail(page))) {
>  		bad_page(page, "PageTail not set", 0);
>  		goto out;
> @@ -874,6 +879,7 @@ static int free_tail_pages_check(struct page *head_page, struct page *page)
>  	}
>  	ret = 0;
>  out:
> +	page->mapping = NULL;
>  	clear_compound_head(page);
>  	return ret;
>  }
> diff --git a/mm/util.c b/mm/util.c
> index 9af1c12b310c..902b65a43899 100644
> --- a/mm/util.c
> +++ b/mm/util.c
> @@ -355,7 +355,9 @@ struct anon_vma *page_anon_vma(struct page *page)
>  
>  struct address_space *page_mapping(struct page *page)
>  {
> -	unsigned long mapping;
> +	struct address_space *mapping;
> +
> +	page = compound_head(page);
>  
>  	/* This happens if someone calls flush_dcache_page on slab page */
>  	if (unlikely(PageSlab(page)))
> @@ -368,10 +370,10 @@ struct address_space *page_mapping(struct page *page)
>  		return swap_address_space(entry);
>  	}
>  
> -	mapping = (unsigned long)page->mapping;
> -	if (mapping & PAGE_MAPPING_FLAGS)
> +	mapping = page->mapping;
> +	if ((unsigned long)mapping & PAGE_MAPPING_FLAGS)
>  		return NULL;
> -	return page->mapping;
> +	return mapping;
>  }
>  
>  int overcommit_ratio_handler(struct ctl_table *table, int write,
> -- 
> 2.5.1
> 
> --
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#1232161 — [PATCH 07/16] page-flags: define behavior SL*B-related flags on compound pages

SL*B uses compound pages and marks head pages with PG_slab.
__SetPageSlab() and __ClearPageSlab() are never called for tail pages.

The same situation with PG_slob_free in SLOB allocator.

PF_NO_TAIL is appropriate for these flags.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
 include/linux/page-flags.h | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index 10b75615ddf2..c9cd82310e2d 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -254,7 +254,8 @@ PAGEFLAG(Dirty, dirty, PF_HEAD) TESTSCFLAG(Dirty, dirty, PF_HEAD)
 PAGEFLAG(LRU, lru, PF_HEAD) __CLEARPAGEFLAG(LRU, lru, PF_HEAD)
 PAGEFLAG(Active, active, PF_HEAD) __CLEARPAGEFLAG(Active, active, PF_HEAD)
 	TESTCLEARFLAG(Active, active, PF_HEAD)
-__PAGEFLAG(Slab, slab, PF_ANY)
+__PAGEFLAG(Slab, slab, PF_NO_TAIL)
+__PAGEFLAG(SlobFree, slob_free, PF_NO_TAIL)
 PAGEFLAG(Checked, checked, PF_NO_COMPOUND)	   /* Used by some filesystems */
 PAGEFLAG(Pinned, pinned, PF_ANY) TESTSCFLAG(Pinned, pinned, PF_ANY)	/* Xen */
 PAGEFLAG(SavePinned, savepinned, PF_ANY);			/* Xen */
@@ -264,8 +265,6 @@ PAGEFLAG(SwapBacked, swapbacked, PF_ANY)
 	__CLEARPAGEFLAG(SwapBacked, swapbacked, PF_ANY)
 	__SETPAGEFLAG(SwapBacked, swapbacked, PF_ANY)
 
-__PAGEFLAG(SlobFree, slob_free, PF_ANY)
-
 /*
  * Private page markings that may be used by the filesystem that owns the page
  * for its own purposes.
-- 
2.5.1

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