<feed xmlns='http://www.w3.org/2005/Atom'>
<title>kernel/linux.git/arch/xtensa/mm/cache.c, branch v6.19.11</title>
<subtitle>Linux kernel stable tree (mirror)</subtitle>
<id>https://git.radix-linux.su/kernel/linux.git/atom?h=v6.19.11</id>
<link rel='self' href='https://git.radix-linux.su/kernel/linux.git/atom?h=v6.19.11'/>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/'/>
<updated>2025-09-13T23:55:07+00:00</updated>
<entry>
<title>mm: introduce memdesc_flags_t</title>
<updated>2025-09-13T23:55:07+00:00</updated>
<author>
<name>Matthew Wilcox (Oracle)</name>
<email>willy@infradead.org</email>
</author>
<published>2025-08-05T17:22:51+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=53fbef56e07df822ea3029109ffca25328c2e5ac'/>
<id>urn:sha1:53fbef56e07df822ea3029109ffca25328c2e5ac</id>
<content type='text'>
Patch series "Add and use memdesc_flags_t".

At some point struct page will be separated from struct slab and struct
folio.  This is a step towards that by introducing a type for the 'flags'
word of all three structures.  This gives us a certain amount of type
safety by establishing that some of these unsigned longs are different
from other unsigned longs in that they contain things like node ID,
section number and zone number in the upper bits.  That lets us have
functions that can be easily called by anyone who has a slab, folio or
page (but not easily by anyone else) to get the node or zone.

There's going to be some unusual merge problems with this as some odd bits
of the kernel decide they want to print out the flags value or something
similar by writing page-&gt;flags and now they'll need to write page-&gt;flags.f
instead.  That's most of the churn here.  Maybe we should be removing
these things from the debug output?


This patch (of 11):

Wrap the unsigned long flags in a typedef.  In upcoming patches, this will
provide a strong hint that you can't just pass a random unsigned long to
functions which take this as an argument.

[willy@infradead.org: s/flags/flags.f/ in several architectures]
  Link: https://lkml.kernel.org/r/aKMgPRLD-WnkPxYm@casper.infradead.org
[nicola.vetrini@gmail.com: mips: fix compilation error]
  Link: https://lore.kernel.org/lkml/CA+G9fYvkpmqGr6wjBNHY=dRp71PLCoi2341JxOudi60yqaeUdg@mail.gmail.com/
  Link: https://lkml.kernel.org/r/20250825214245.1838158-1-nicola.vetrini@gmail.com
Link: https://lkml.kernel.org/r/20250805172307.1302730-1-willy@infradead.org
Link: https://lkml.kernel.org/r/20250805172307.1302730-2-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) &lt;willy@infradead.org&gt;
Signed-off-by: Matthew Wilcox (Oracle) &lt;willy@infradead.org&gt;
Acked-by: Zi Yan &lt;ziy@nvidia.com&gt;
Cc: Shakeel Butt &lt;shakeel.butt@linux.dev&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
</content>
</entry>
<entry>
<title>xtensa: remove uses of PG_arch_1 on individual pages</title>
<updated>2024-04-26T03:56:13+00:00</updated>
<author>
<name>Matthew Wilcox (Oracle)</name>
<email>willy@infradead.org</email>
</author>
<published>2024-03-26T17:10:24+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=fa92722e382b3926a371d7432bbfde5efee2f2be'/>
<id>urn:sha1:fa92722e382b3926a371d7432bbfde5efee2f2be</id>
<content type='text'>
Since switching to the new page table range API, we disregard the
PG_arch_1 (aka dcache dirty) flag on tail pages, and only pay attention to
it on the folio.  Fix these two missed spots where we were setting it on
arbitrary pages.

Link: https://lkml.kernel.org/r/20240326171045.410737-3-willy@infradead.org
Reported-by: Svetly Todorov &lt;svetly.todorov@memverge.com&gt;
Signed-off-by: Matthew Wilcox (Oracle) &lt;willy@infradead.org&gt;
Reviewed-by: Svetly Todorov &lt;svetly.todorov@memverge.com&gt;	[xtensa]
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
</content>
</entry>
<entry>
<title>xtensa: implement the new page table range API</title>
<updated>2023-08-24T23:20:24+00:00</updated>
<author>
<name>Matthew Wilcox (Oracle)</name>
<email>willy@infradead.org</email>
</author>
<published>2023-08-02T15:13:57+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=4fbb7e7f47dbc631a9f5bad3171ccbca171ed1d3'/>
<id>urn:sha1:4fbb7e7f47dbc631a9f5bad3171ccbca171ed1d3</id>
<content type='text'>
Add PFN_PTE_SHIFT, update_mmu_cache_range(), flush_dcache_folio() and
flush_icache_pages().

Link: https://lkml.kernel.org/r/20230802151406.3735276-30-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) &lt;willy@infradead.org&gt;
Acked-by: Mike Rapoport (IBM) &lt;rppt@kernel.org&gt;
Cc: Max Filippov &lt;jcmvbkbc@gmail.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
</content>
</entry>
<entry>
<title>xtensa: simplify coherent_kvaddr logic</title>
<updated>2021-04-04T22:39:03+00:00</updated>
<author>
<name>Max Filippov</name>
<email>jcmvbkbc@gmail.com</email>
</author>
<published>2021-02-17T06:39:41+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=4f22ca7e192ee313a83f8093ba5b5b2ca72d10e4'/>
<id>urn:sha1:4f22ca7e192ee313a83f8093ba5b5b2ca72d10e4</id>
<content type='text'>
Functions coherent_kvaddr, clear_page_alias and copy_page_alias use
physical address 0 as a special value that means 'this page is in the
KSEG mapping and its existing virtual address has the same color as the
virtual address of its future mapping, so don't map it to the
TLBTEMP_BASE area'.

Simplify this logic and drop special handling of low memory pages/pages
with coherent mapping and always use TLBTEMP_BASE area.

Signed-off-by: Max Filippov &lt;jcmvbkbc@gmail.com&gt;
</content>
</entry>
<entry>
<title>xtensa: disable preemption around cache alias management calls</title>
<updated>2020-11-16T10:13:16+00:00</updated>
<author>
<name>Max Filippov</name>
<email>jcmvbkbc@gmail.com</email>
</author>
<published>2020-11-16T09:38:59+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=3a860d165eb5f4d7cf0bf81ef6a5b5c5e1754422'/>
<id>urn:sha1:3a860d165eb5f4d7cf0bf81ef6a5b5c5e1754422</id>
<content type='text'>
Although cache alias management calls set up and tear down TLB entries
and fast_second_level_miss is able to restore TLB entry should it be
evicted they absolutely cannot preempt each other because they use the
same TLBTEMP area for different purposes.
Disable preemption around all cache alias management calls to enforce
that.

Cc: stable@vger.kernel.org
Signed-off-by: Max Filippov &lt;jcmvbkbc@gmail.com&gt;
</content>
</entry>
<entry>
<title>mm: remove unneeded includes of &lt;asm/pgalloc.h&gt;</title>
<updated>2020-08-07T18:33:26+00:00</updated>
<author>
<name>Mike Rapoport</name>
<email>rppt@linux.ibm.com</email>
</author>
<published>2020-08-07T06:22:28+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=ca15ca406f660ad5fab55b851d2b269ce915c88d'/>
<id>urn:sha1:ca15ca406f660ad5fab55b851d2b269ce915c88d</id>
<content type='text'>
Patch series "mm: cleanup usage of &lt;asm/pgalloc.h&gt;"

Most architectures have very similar versions of pXd_alloc_one() and
pXd_free_one() for intermediate levels of page table.  These patches add
generic versions of these functions in &lt;asm-generic/pgalloc.h&gt; and enable
use of the generic functions where appropriate.

In addition, functions declared and defined in &lt;asm/pgalloc.h&gt; headers are
used mostly by core mm and early mm initialization in arch and there is no
actual reason to have the &lt;asm/pgalloc.h&gt; included all over the place.
The first patch in this series removes unneeded includes of
&lt;asm/pgalloc.h&gt;

In the end it didn't work out as neatly as I hoped and moving
pXd_alloc_track() definitions to &lt;asm-generic/pgalloc.h&gt; would require
unnecessary changes to arches that have custom page table allocations, so
I've decided to move lib/ioremap.c to mm/ and make pgalloc-track.h local
to mm/.

This patch (of 8):

In most cases &lt;asm/pgalloc.h&gt; header is required only for allocations of
page table memory.  Most of the .c files that include that header do not
use symbols declared in &lt;asm/pgalloc.h&gt; and do not require that header.

As for the other header files that used to include &lt;asm/pgalloc.h&gt;, it is
possible to move that include into the .c file that actually uses symbols
from &lt;asm/pgalloc.h&gt; and drop the include from the header file.

The process was somewhat automated using

	sed -i -E '/[&lt;"]asm\/pgalloc\.h/d' \
                $(grep -L -w -f /tmp/xx \
                        $(git grep -E -l '[&lt;"]asm/pgalloc\.h'))

where /tmp/xx contains all the symbols defined in
arch/*/include/asm/pgalloc.h.

[rppt@linux.ibm.com: fix powerpc warning]

Signed-off-by: Mike Rapoport &lt;rppt@linux.ibm.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Reviewed-by: Pekka Enberg &lt;penberg@kernel.org&gt;
Acked-by: Geert Uytterhoeven &lt;geert@linux-m68k.org&gt;	[m68k]
Cc: Abdul Haleem &lt;abdhalee@linux.vnet.ibm.com&gt;
Cc: Andy Lutomirski &lt;luto@kernel.org&gt;
Cc: Arnd Bergmann &lt;arnd@arndb.de&gt;
Cc: Christophe Leroy &lt;christophe.leroy@csgroup.eu&gt;
Cc: Joerg Roedel &lt;joro@8bytes.org&gt;
Cc: Max Filippov &lt;jcmvbkbc@gmail.com&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Satheesh Rajendran &lt;sathnaga@linux.vnet.ibm.com&gt;
Cc: Stafford Horne &lt;shorne@gmail.com&gt;
Cc: Stephen Rothwell &lt;sfr@canb.auug.org.au&gt;
Cc: Steven Rostedt &lt;rostedt@goodmis.org&gt;
Cc: Joerg Roedel &lt;jroedel@suse.de&gt;
Cc: Matthew Wilcox &lt;willy@infradead.org&gt;
Link: http://lkml.kernel.org/r/20200627143453.31835-1-rppt@kernel.org
Link: http://lkml.kernel.org/r/20200627143453.31835-2-rppt@kernel.org
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
</entry>
<entry>
<title>mm: reorder includes after introduction of linux/pgtable.h</title>
<updated>2020-06-09T16:39:13+00:00</updated>
<author>
<name>Mike Rapoport</name>
<email>rppt@linux.ibm.com</email>
</author>
<published>2020-06-09T04:32:42+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=65fddcfca8ad14778f71a57672fd01e8112d30fa'/>
<id>urn:sha1:65fddcfca8ad14778f71a57672fd01e8112d30fa</id>
<content type='text'>
The replacement of &lt;asm/pgrable.h&gt; with &lt;linux/pgtable.h&gt; made the include
of the latter in the middle of asm includes.  Fix this up with the aid of
the below script and manual adjustments here and there.

	import sys
	import re

	if len(sys.argv) is not 3:
	    print "USAGE: %s &lt;file&gt; &lt;header&gt;" % (sys.argv[0])
	    sys.exit(1)

	hdr_to_move="#include &lt;linux/%s&gt;" % sys.argv[2]
	moved = False
	in_hdrs = False

	with open(sys.argv[1], "r") as f:
	    lines = f.readlines()
	    for _line in lines:
		line = _line.rstrip('
')
		if line == hdr_to_move:
		    continue
		if line.startswith("#include &lt;linux/"):
		    in_hdrs = True
		elif not moved and in_hdrs:
		    moved = True
		    print hdr_to_move
		print line

Signed-off-by: Mike Rapoport &lt;rppt@linux.ibm.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Cc: Arnd Bergmann &lt;arnd@arndb.de&gt;
Cc: Borislav Petkov &lt;bp@alien8.de&gt;
Cc: Brian Cain &lt;bcain@codeaurora.org&gt;
Cc: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
Cc: Chris Zankel &lt;chris@zankel.net&gt;
Cc: "David S. Miller" &lt;davem@davemloft.net&gt;
Cc: Geert Uytterhoeven &lt;geert@linux-m68k.org&gt;
Cc: Greentime Hu &lt;green.hu@gmail.com&gt;
Cc: Greg Ungerer &lt;gerg@linux-m68k.org&gt;
Cc: Guan Xuetao &lt;gxt@pku.edu.cn&gt;
Cc: Guo Ren &lt;guoren@kernel.org&gt;
Cc: Heiko Carstens &lt;heiko.carstens@de.ibm.com&gt;
Cc: Helge Deller &lt;deller@gmx.de&gt;
Cc: Ingo Molnar &lt;mingo@redhat.com&gt;
Cc: Ley Foon Tan &lt;ley.foon.tan@intel.com&gt;
Cc: Mark Salter &lt;msalter@redhat.com&gt;
Cc: Matthew Wilcox &lt;willy@infradead.org&gt;
Cc: Matt Turner &lt;mattst88@gmail.com&gt;
Cc: Max Filippov &lt;jcmvbkbc@gmail.com&gt;
Cc: Michael Ellerman &lt;mpe@ellerman.id.au&gt;
Cc: Michal Simek &lt;monstr@monstr.eu&gt;
Cc: Nick Hu &lt;nickhu@andestech.com&gt;
Cc: Paul Walmsley &lt;paul.walmsley@sifive.com&gt;
Cc: Richard Weinberger &lt;richard@nod.at&gt;
Cc: Rich Felker &lt;dalias@libc.org&gt;
Cc: Russell King &lt;linux@armlinux.org.uk&gt;
Cc: Stafford Horne &lt;shorne@gmail.com&gt;
Cc: Thomas Bogendoerfer &lt;tsbogend@alpha.franken.de&gt;
Cc: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Cc: Tony Luck &lt;tony.luck@intel.com&gt;
Cc: Vincent Chen &lt;deanbo422@gmail.com&gt;
Cc: Vineet Gupta &lt;vgupta@synopsys.com&gt;
Cc: Will Deacon &lt;will@kernel.org&gt;
Cc: Yoshinori Sato &lt;ysato@users.sourceforge.jp&gt;
Link: http://lkml.kernel.org/r/20200514170327.31389-4-rppt@kernel.org
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
</entry>
<entry>
<title>mm: introduce include/linux/pgtable.h</title>
<updated>2020-06-09T16:39:13+00:00</updated>
<author>
<name>Mike Rapoport</name>
<email>rppt@linux.ibm.com</email>
</author>
<published>2020-06-09T04:32:38+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=ca5999fde0a1761665a38e4c9a72dbcd7d190a81'/>
<id>urn:sha1:ca5999fde0a1761665a38e4c9a72dbcd7d190a81</id>
<content type='text'>
The include/linux/pgtable.h is going to be the home of generic page table
manipulation functions.

Start with moving asm-generic/pgtable.h to include/linux/pgtable.h and
make the latter include asm/pgtable.h.

Signed-off-by: Mike Rapoport &lt;rppt@linux.ibm.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Cc: Arnd Bergmann &lt;arnd@arndb.de&gt;
Cc: Borislav Petkov &lt;bp@alien8.de&gt;
Cc: Brian Cain &lt;bcain@codeaurora.org&gt;
Cc: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
Cc: Chris Zankel &lt;chris@zankel.net&gt;
Cc: "David S. Miller" &lt;davem@davemloft.net&gt;
Cc: Geert Uytterhoeven &lt;geert@linux-m68k.org&gt;
Cc: Greentime Hu &lt;green.hu@gmail.com&gt;
Cc: Greg Ungerer &lt;gerg@linux-m68k.org&gt;
Cc: Guan Xuetao &lt;gxt@pku.edu.cn&gt;
Cc: Guo Ren &lt;guoren@kernel.org&gt;
Cc: Heiko Carstens &lt;heiko.carstens@de.ibm.com&gt;
Cc: Helge Deller &lt;deller@gmx.de&gt;
Cc: Ingo Molnar &lt;mingo@redhat.com&gt;
Cc: Ley Foon Tan &lt;ley.foon.tan@intel.com&gt;
Cc: Mark Salter &lt;msalter@redhat.com&gt;
Cc: Matthew Wilcox &lt;willy@infradead.org&gt;
Cc: Matt Turner &lt;mattst88@gmail.com&gt;
Cc: Max Filippov &lt;jcmvbkbc@gmail.com&gt;
Cc: Michael Ellerman &lt;mpe@ellerman.id.au&gt;
Cc: Michal Simek &lt;monstr@monstr.eu&gt;
Cc: Nick Hu &lt;nickhu@andestech.com&gt;
Cc: Paul Walmsley &lt;paul.walmsley@sifive.com&gt;
Cc: Richard Weinberger &lt;richard@nod.at&gt;
Cc: Rich Felker &lt;dalias@libc.org&gt;
Cc: Russell King &lt;linux@armlinux.org.uk&gt;
Cc: Stafford Horne &lt;shorne@gmail.com&gt;
Cc: Thomas Bogendoerfer &lt;tsbogend@alpha.franken.de&gt;
Cc: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Cc: Tony Luck &lt;tony.luck@intel.com&gt;
Cc: Vincent Chen &lt;deanbo422@gmail.com&gt;
Cc: Vineet Gupta &lt;vgupta@synopsys.com&gt;
Cc: Will Deacon &lt;will@kernel.org&gt;
Cc: Yoshinori Sato &lt;ysato@users.sourceforge.jp&gt;
Link: http://lkml.kernel.org/r/20200514170327.31389-3-rppt@kernel.org
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
</entry>
<entry>
<title>mm: remove include/linux/bootmem.h</title>
<updated>2018-10-31T15:54:16+00:00</updated>
<author>
<name>Mike Rapoport</name>
<email>rppt@linux.vnet.ibm.com</email>
</author>
<published>2018-10-30T22:09:49+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=57c8a661d95dff48dd9c2f2496139082bbaf241a'/>
<id>urn:sha1:57c8a661d95dff48dd9c2f2496139082bbaf241a</id>
<content type='text'>
Move remaining definitions and declarations from include/linux/bootmem.h
into include/linux/memblock.h and remove the redundant header.

The includes were replaced with the semantic patch below and then
semi-automated removal of duplicated '#include &lt;linux/memblock.h&gt;

@@
@@
- #include &lt;linux/bootmem.h&gt;
+ #include &lt;linux/memblock.h&gt;

[sfr@canb.auug.org.au: dma-direct: fix up for the removal of linux/bootmem.h]
  Link: http://lkml.kernel.org/r/20181002185342.133d1680@canb.auug.org.au
[sfr@canb.auug.org.au: powerpc: fix up for removal of linux/bootmem.h]
  Link: http://lkml.kernel.org/r/20181005161406.73ef8727@canb.auug.org.au
[sfr@canb.auug.org.au: x86/kaslr, ACPI/NUMA: fix for linux/bootmem.h removal]
  Link: http://lkml.kernel.org/r/20181008190341.5e396491@canb.auug.org.au
Link: http://lkml.kernel.org/r/1536927045-23536-30-git-send-email-rppt@linux.vnet.ibm.com
Signed-off-by: Mike Rapoport &lt;rppt@linux.vnet.ibm.com&gt;
Signed-off-by: Stephen Rothwell &lt;sfr@canb.auug.org.au&gt;
Acked-by: Michal Hocko &lt;mhocko@suse.com&gt;
Cc: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
Cc: Chris Zankel &lt;chris@zankel.net&gt;
Cc: "David S. Miller" &lt;davem@davemloft.net&gt;
Cc: Geert Uytterhoeven &lt;geert@linux-m68k.org&gt;
Cc: Greentime Hu &lt;green.hu@gmail.com&gt;
Cc: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Cc: Guan Xuetao &lt;gxt@pku.edu.cn&gt;
Cc: Ingo Molnar &lt;mingo@redhat.com&gt;
Cc: "James E.J. Bottomley" &lt;jejb@parisc-linux.org&gt;
Cc: Jonas Bonn &lt;jonas@southpole.se&gt;
Cc: Jonathan Corbet &lt;corbet@lwn.net&gt;
Cc: Ley Foon Tan &lt;lftan@altera.com&gt;
Cc: Mark Salter &lt;msalter@redhat.com&gt;
Cc: Martin Schwidefsky &lt;schwidefsky@de.ibm.com&gt;
Cc: Matt Turner &lt;mattst88@gmail.com&gt;
Cc: Michael Ellerman &lt;mpe@ellerman.id.au&gt;
Cc: Michal Simek &lt;monstr@monstr.eu&gt;
Cc: Palmer Dabbelt &lt;palmer@sifive.com&gt;
Cc: Paul Burton &lt;paul.burton@mips.com&gt;
Cc: Richard Kuo &lt;rkuo@codeaurora.org&gt;
Cc: Richard Weinberger &lt;richard@nod.at&gt;
Cc: Rich Felker &lt;dalias@libc.org&gt;
Cc: Russell King &lt;linux@armlinux.org.uk&gt;
Cc: Serge Semin &lt;fancer.lancer@gmail.com&gt;
Cc: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Cc: Tony Luck &lt;tony.luck@intel.com&gt;
Cc: Vineet Gupta &lt;vgupta@synopsys.com&gt;
Cc: Yoshinori Sato &lt;ysato@users.sourceforge.jp&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
</entry>
<entry>
<title>mm: fix races between swapoff and flush dcache</title>
<updated>2018-04-06T04:36:26+00:00</updated>
<author>
<name>Huang Ying</name>
<email>ying.huang@intel.com</email>
</author>
<published>2018-04-05T23:24:39+00:00</published>
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Thanks to commit 4b3ef9daa4fc ("mm/swap: split swap cache into 64MB
trunks"), after swapoff the address_space associated with the swap
device will be freed.  So page_mapping() users which may touch the
address_space need some kind of mechanism to prevent the address_space
from being freed during accessing.

The dcache flushing functions (flush_dcache_page(), etc) in architecture
specific code may access the address_space of swap device for anonymous
pages in swap cache via page_mapping() function.  But in some cases
there are no mechanisms to prevent the swap device from being swapoff,
for example,

  CPU1					CPU2
  __get_user_pages()			swapoff()
    flush_dcache_page()
      mapping = page_mapping()
        ...				  exit_swap_address_space()
        ...				    kvfree(spaces)
        mapping_mapped(mapping)

The address space may be accessed after being freed.

But from cachetlb.txt and Russell King, flush_dcache_page() only care
about file cache pages, for anonymous pages, flush_anon_page() should be
used.  The implementation of flush_dcache_page() in all architectures
follows this too.  They will check whether page_mapping() is NULL and
whether mapping_mapped() is true to determine whether to flush the
dcache immediately.  And they will use interval tree (mapping-&gt;i_mmap)
to find all user space mappings.  While mapping_mapped() and
mapping-&gt;i_mmap isn't used by anonymous pages in swap cache at all.

So, to fix the race between swapoff and flush dcache, __page_mapping()
is add to return the address_space for file cache pages and NULL
otherwise.  All page_mapping() invoking in flush dcache functions are
replaced with page_mapping_file().

[akpm@linux-foundation.org: simplify page_mapping_file(), per Mike]
Link: http://lkml.kernel.org/r/20180305083634.15174-1-ying.huang@intel.com
Signed-off-by: "Huang, Ying" &lt;ying.huang@intel.com&gt;
Reviewed-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Cc: Minchan Kim &lt;minchan@kernel.org&gt;
Cc: Michal Hocko &lt;mhocko@suse.com&gt;
Cc: Johannes Weiner &lt;hannes@cmpxchg.org&gt;
Cc: Mel Gorman &lt;mgorman@techsingularity.net&gt;
Cc: Dave Hansen &lt;dave.hansen@intel.com&gt;
Cc: Chen Liqin &lt;liqin.linux@gmail.com&gt;
Cc: Russell King &lt;linux@armlinux.org.uk&gt;
Cc: Yoshinori Sato &lt;ysato@users.sourceforge.jp&gt;
Cc: "James E.J. Bottomley" &lt;jejb@parisc-linux.org&gt;
Cc: Guan Xuetao &lt;gxt@mprc.pku.edu.cn&gt;
Cc: "David S. Miller" &lt;davem@davemloft.net&gt;
Cc: Chris Zankel &lt;chris@zankel.net&gt;
Cc: Vineet Gupta &lt;vgupta@synopsys.com&gt;
Cc: Ley Foon Tan &lt;lftan@altera.com&gt;
Cc: Ralf Baechle &lt;ralf@linux-mips.org&gt;
Cc: Andi Kleen &lt;ak@linux.intel.com&gt;
Cc: Mike Rapoport &lt;rppt@linux.vnet.ibm.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
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