Commit Graph

257 Commits

Author SHA1 Message Date
Thomas Gleixner
2025cf9e19 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 288
Based on 1 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms and conditions of the gnu general public license
  version 2 as published by the free software foundation this program
  is distributed in the hope it will be useful but without any
  warranty without even the implied warranty of merchantability or
  fitness for a particular purpose see the gnu general public license
  for more details

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-only

has been chosen to replace the boilerplate/reference in 263 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Alexios Zavras <alexios.zavras@intel.com>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190529141901.208660670@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-06-05 17:36:37 +02:00
Aneesh Kumar K.V
024eee0e83 mm: page_mkclean vs MADV_DONTNEED race
MADV_DONTNEED is handled with mmap_sem taken in read mode.  We call
page_mkclean without holding mmap_sem.

MADV_DONTNEED implies that pages in the region are unmapped and subsequent
access to the pages in that range is handled as a new page fault.  This
implies that if we don't have parallel access to the region when
MADV_DONTNEED is run we expect those range to be unallocated.

w.r.t page_mkclean() we need to make sure that we don't break the
MADV_DONTNEED semantics.  MADV_DONTNEED check for pmd_none without holding
pmd_lock.  This implies we skip the pmd if we temporarily mark pmd none.
Avoid doing that while marking the page clean.

Keep the sequence same for dax too even though we don't support
MADV_DONTNEED for dax mapping

The bug was noticed by code review and I didn't observe any failures w.r.t
test run.  This is similar to

commit 58ceeb6bec
Author: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Date:   Thu Apr 13 14:56:26 2017 -0700

    thp: fix MADV_DONTNEED vs. MADV_FREE race

commit ced108037c
Author: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Date:   Thu Apr 13 14:56:20 2017 -0700

    thp: fix MADV_DONTNEED vs. numa balancing race

Link: http://lkml.kernel.org/r/20190321040610.14226-1-aneesh.kumar@linux.ibm.com
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc:"Kirill A . Shutemov" <kirill@shutemov.name>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-05-14 09:47:48 -07:00
Dan Williams
fce86ff580 mm/huge_memory: fix vmf_insert_pfn_{pmd, pud}() crash, handle unaligned addresses
Starting with c6f3c5ee40 ("mm/huge_memory.c: fix modifying of page
protection by insert_pfn_pmd()") vmf_insert_pfn_pmd() internally calls
pmdp_set_access_flags().  That helper enforces a pmd aligned @address
argument via VM_BUG_ON() assertion.

Update the implementation to take a 'struct vm_fault' argument directly
and apply the address alignment fixup internally to fix crash signatures
like:

    kernel BUG at arch/x86/mm/pgtable.c:515!
    invalid opcode: 0000 [#1] SMP NOPTI
    CPU: 51 PID: 43713 Comm: java Tainted: G           OE     4.19.35 #1
    [..]
    RIP: 0010:pmdp_set_access_flags+0x48/0x50
    [..]
    Call Trace:
     vmf_insert_pfn_pmd+0x198/0x350
     dax_iomap_fault+0xe82/0x1190
     ext4_dax_huge_fault+0x103/0x1f0
     ? __switch_to_asm+0x40/0x70
     __handle_mm_fault+0x3f6/0x1370
     ? __switch_to_asm+0x34/0x70
     ? __switch_to_asm+0x40/0x70
     handle_mm_fault+0xda/0x200
     __do_page_fault+0x249/0x4f0
     do_page_fault+0x32/0x110
     ? page_fault+0x8/0x30
     page_fault+0x1e/0x30

Link: http://lkml.kernel.org/r/155741946350.372037.11148198430068238140.stgit@dwillia2-desk3.amr.corp.intel.com
Fixes: c6f3c5ee40 ("mm/huge_memory.c: fix modifying of page protection by insert_pfn_pmd()")
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Reported-by: Piotr Balcer <piotr.balcer@intel.com>
Tested-by: Yan Ma <yan.ma@intel.com>
Tested-by: Pankaj Gupta <pagupta@redhat.com>
Reviewed-by: Matthew Wilcox <willy@infradead.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Chandan Rajendra <chandan@linux.ibm.com>
Cc: Souptick Joarder <jrdr.linux@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-05-14 09:47:44 -07:00
Aneesh Kumar K.V
11cf9d863d fs/dax: Deposit pagetable even when installing zero page
Architectures like ppc64 use the deposited page table to store hardware
page table slot information. Make sure we deposit a page table when
using zero page at the pmd level for hash.

Without this we hit

Unable to handle kernel paging request for data at address 0x00000000
Faulting instruction address: 0xc000000000082a74
Oops: Kernel access of bad area, sig: 11 [#1]
....

NIP [c000000000082a74] __hash_page_thp+0x224/0x5b0
LR [c0000000000829a4] __hash_page_thp+0x154/0x5b0
Call Trace:
 hash_page_mm+0x43c/0x740
 do_hash_page+0x2c/0x3c
 copy_from_iter_flushcache+0xa4/0x4a0
 pmem_copy_from_iter+0x2c/0x50 [nd_pmem]
 dax_copy_from_iter+0x40/0x70
 dax_iomap_actor+0x134/0x360
 iomap_apply+0xfc/0x1b0
 dax_iomap_rw+0xac/0x130
 ext4_file_write_iter+0x254/0x460 [ext4]
 __vfs_write+0x120/0x1e0
 vfs_write+0xd8/0x220
 SyS_write+0x6c/0x110
 system_call+0x3c/0x130

Fixes: b5beae5e22 ("powerpc/pseries: Add driver for PAPR SCM regions")
Cc: <stable@vger.kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2019-03-13 13:58:46 -07:00
Matthew Wilcox
e4b3448bc3 dax: Flush partial PMDs correctly
The radix tree would rewind the index in an iterator to the lowest index
of a multi-slot entry.  The XArray iterators instead leave the index
unchanged, but I overlooked that when converting DAX from the radix tree
to the XArray.  Adjust the index that we use for flushing to the start
of the PMD range.

Fixes: c1901cd33c ("page cache: Convert find_get_entries_tag to XArray")
Cc: <stable@vger.kernel.org>
Reported-by: Piotr Balcer <piotr.balcer@intel.com>
Tested-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2019-03-01 17:24:48 -08:00
Ira Weiny
0cefc36b32 fs/dax: NIT fix comment regarding start/end vs range
Fixes: ac46d4f3c4 ("mm/mmu_notifier: use structure for invalidate_range_start/end calls v2")
Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2019-02-12 20:24:15 -08:00
Souptick Joarder
c9aed74e6a fs/dax: Convert to use vmf_error()
This code is converted to use vmf_error().

Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2019-02-12 20:22:45 -08:00
Linus Torvalds
2a1a2c1a76 dax fix 4.21
* Clean up unnecessary usage of prepare_to_wait_exclusive()
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Merge tag 'dax-fix-4.21' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm

Pull dax fix from Dan Williams:
 "Clean up unnecessary usage of prepare_to_wait_exclusive().

  While I feel a bit silly sending a single-commit pull-request there is
  nothing else queued up for dax this cycle. This change has shipped in
  -next for multiple releases"

* tag 'dax-fix-4.21' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm:
  dax: Use non-exclusive wait in wait_entry_unlocked()
2018-12-31 09:46:39 -08:00
Jérôme Glisse
ac46d4f3c4 mm/mmu_notifier: use structure for invalidate_range_start/end calls v2
To avoid having to change many call sites everytime we want to add a
parameter use a structure to group all parameters for the mmu_notifier
invalidate_range_start/end cakks.  No functional changes with this patch.

[akpm@linux-foundation.org: coding style fixes]
Link: http://lkml.kernel.org/r/20181205053628.3210-3-jglisse@redhat.com
Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
Acked-by: Christian König <christian.koenig@amd.com>
Acked-by: Jan Kara <jack@suse.cz>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Cc: Ross Zwisler <zwisler@kernel.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krcmar <rkrcmar@redhat.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Felix Kuehling <felix.kuehling@amd.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
From: Jérôme Glisse <jglisse@redhat.com>
Subject: mm/mmu_notifier: use structure for invalidate_range_start/end calls v3

fix build warning in migrate.c when CONFIG_MMU_NOTIFIER=n

Link: http://lkml.kernel.org/r/20181213171330.8489-3-jglisse@redhat.com
Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-12-28 12:11:50 -08:00
Dan Williams
d8a706414a dax: Use non-exclusive wait in wait_entry_unlocked()
get_unlocked_entry() uses an exclusive wait because it is guaranteed to
eventually obtain the lock and follow on with an unlock+wakeup cycle.
The wait_entry_unlocked() path does not have the same guarantee. Rather
than open-code an extra wakeup, just switch to a non-exclusive wait.

Cc: Jan Kara <jack@suse.cz>
Cc: Matthew Wilcox <willy@infradead.org>
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2018-12-21 11:35:53 -08:00
Matthew Wilcox
27359fd6e5 dax: Fix unlock mismatch with updated API
Internal to dax_unlock_mapping_entry(), dax_unlock_entry() is used to
store a replacement entry in the Xarray at the given xas-index with the
DAX_LOCKED bit clear. When called, dax_unlock_entry() expects the unlocked
value of the entry relative to the current Xarray state to be specified.

In most contexts dax_unlock_entry() is operating in the same scope as
the matched dax_lock_entry(). However, in the dax_unlock_mapping_entry()
case the implementation needs to recall the original entry. In the case
where the original entry is a 'pmd' entry it is possible that the pfn
performed to do the lookup is misaligned to the value retrieved in the
Xarray.

Change the api to return the unlock cookie from dax_lock_page() and pass
it to dax_unlock_page(). This fixes a bug where dax_unlock_page() was
assuming that the page was PMD-aligned if the entry was a PMD entry with
signatures like:

 WARNING: CPU: 38 PID: 1396 at fs/dax.c:340 dax_insert_entry+0x2b2/0x2d0
 RIP: 0010:dax_insert_entry+0x2b2/0x2d0
 [..]
 Call Trace:
  dax_iomap_pte_fault.isra.41+0x791/0xde0
  ext4_dax_huge_fault+0x16f/0x1f0
  ? up_read+0x1c/0xa0
  __do_fault+0x1f/0x160
  __handle_mm_fault+0x1033/0x1490
  handle_mm_fault+0x18b/0x3d0

Link: https://lkml.kernel.org/r/20181130154902.GL10377@bombadil.infradead.org
Fixes: 9f32d22130 ("dax: Convert dax_lock_mapping_entry to XArray")
Reported-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Matthew Wilcox <willy@infradead.org>
Tested-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2018-12-04 21:32:00 -08:00
Matthew Wilcox
55e56f06ed dax: Don't access a freed inode
After we drop the i_pages lock, the inode can be freed at any time.
The get_unlocked_entry() code has no choice but to reacquire the lock,
so it can't be used here.  Create a new wait_entry_unlocked() which takes
care not to acquire the lock or dereference the address_space in any way.

Fixes: c2a7d2a115 ("filesystem-dax: Introduce dax_lock_mapping_entry()")
Cc: <stable@vger.kernel.org>
Signed-off-by: Matthew Wilcox <willy@infradead.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2018-11-28 11:08:42 -08:00
Matthew Wilcox
c93db7bb6e dax: Check page->mapping isn't NULL
If we race with inode destroy, it's possible for page->mapping to be
NULL before we even enter this routine, as well as after having slept
waiting for the dax entry to become unlocked.

Fixes: c2a7d2a115 ("filesystem-dax: Introduce dax_lock_mapping_entry()")
Cc: <stable@vger.kernel.org>
Reported-by: Jan Kara <jack@suse.cz>
Signed-off-by: Matthew Wilcox <willy@infradead.org>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2018-11-28 11:08:08 -08:00
Matthew Wilcox
25bbe21bf4 dax: Avoid losing wakeup in dax_lock_mapping_entry
After calling get_unlocked_entry(), you have to call
put_unlocked_entry() to avoid subsequent waiters losing wakeups.

Fixes: c2a7d2a115 ("filesystem-dax: Introduce dax_lock_mapping_entry()")
Cc: stable@vger.kernel.org
Signed-off-by: Matthew Wilcox <willy@infradead.org>
2018-11-19 09:40:58 -05:00
Matthew Wilcox
0e40de0338 dax: Fix huge page faults
Using xas_load() with a PMD-sized xa_state would work if either a
PMD-sized entry was present or a PTE sized entry was present in the
first 64 entries (of the 512 PTEs in a PMD on x86).  If there was no
PTE in the first 64 entries, grab_mapping_entry() would believe there
were no entries present, allocate a PMD-sized entry and overwrite the
PTE in the page cache.

Use xas_find_conflict() instead which turns out to simplify
both get_unlocked_entry() and grab_mapping_entry().  Also remove a
WARN_ON_ONCE from grab_mapping_entry() as it will have already triggered
in get_unlocked_entry().

Fixes: cfc93c6c6c ("dax: Convert dax_insert_pfn_mkwrite to XArray")
Signed-off-by: Matthew Wilcox <willy@infradead.org>
2018-11-17 12:07:53 -05:00
Matthew Wilcox
fda490d39f dax: Fix dax_unlock_mapping_entry for PMD pages
Device DAX PMD pages do not set the PageHead bit for compound pages.
Fix for now by retrieving the PMD bit from the entry, but eventually we
will be passed the page size by the caller.

Reported-by: Dan Williams <dan.j.williams@intel.com>
Fixes: 9f32d22130 ("dax: Convert dax_lock_mapping_entry to XArray")
Signed-off-by: Matthew Wilcox <willy@infradead.org>
2018-11-17 12:07:52 -05:00
Matthew Wilcox
c5bbd4515a dax: Reinstate RCU protection of inode
For the device-dax case, it is possible that the inode can go away
underneath us.  The rcu_read_lock() was there to prevent it from
being freed, and not (as I thought) to protect the tree.  Bring back
the rcu_read_lock() protection.  Also add a little kernel-doc; while
this function is not exported to modules, it is used from outside dax.c

Reported-by: Dan Williams <dan.j.williams@intel.com>
Fixes: 9f32d22130 ("dax: Convert dax_lock_mapping_entry to XArray")
Signed-off-by: Matthew Wilcox <willy@infradead.org>
2018-11-16 16:38:50 -05:00
Matthew Wilcox
7ae2ea7dc4 dax: Make sure the unlocking entry isn't locked
I wrote the semantics in the commit message, but didn't document it in
the source code.  Use a BUG_ON instead (if any code does do this, it's
really buggy; we can't recover and it's worth taking the machine down).

Signed-off-by: Matthew Wilcox <willy@infradead.org>
2018-11-16 16:38:50 -05:00
Matthew Wilcox
6d7cd8c137 dax: Remove optimisation from dax_lock_mapping_entry
Skipping some of the revalidation after we sleep can lead to returning
a mapping which has already been freed.  Just drop this optimisation.

Reported-by: Dan Williams <dan.j.williams@intel.com>
Fixes: 9f32d22130 ("dax: Convert dax_lock_mapping_entry to XArray")
Signed-off-by: Matthew Wilcox <willy@infradead.org>
2018-11-16 16:38:49 -05:00
Matthew Wilcox
b15cd80068 dax: Convert page fault handlers to XArray
This is the last part of DAX to be converted to the XArray so
remove all the old helper functions.

Signed-off-by: Matthew Wilcox <willy@infradead.org>
2018-10-21 10:46:44 -04:00
Matthew Wilcox
9f32d22130 dax: Convert dax_lock_mapping_entry to XArray
Instead of always retrying when we slept, only retry if the page has
moved.

Signed-off-by: Matthew Wilcox <willy@infradead.org>
2018-10-21 10:46:44 -04:00
Matthew Wilcox
9fc747f68d dax: Convert dax writeback to XArray
Use XArray iteration instead of a pagevec.

Signed-off-by: Matthew Wilcox <willy@infradead.org>
2018-10-21 10:46:43 -04:00
Matthew Wilcox
07f2d89cc2 dax: Convert __dax_invalidate_entry to XArray
Avoids walking the radix tree multiple times looking for tags.

Signed-off-by: Matthew Wilcox <willy@infradead.org>
2018-10-21 10:46:43 -04:00
Matthew Wilcox
084a899008 dax: Convert dax_layout_busy_page to XArray
Instead of using a pagevec, just use the XArray iterators.  Add a
conditional rescheduling point which probably should have been there in
the original.

Signed-off-by: Matthew Wilcox <willy@infradead.org>
2018-10-21 10:46:43 -04:00
Matthew Wilcox
cfc93c6c6c dax: Convert dax_insert_pfn_mkwrite to XArray
Add some XArray-based helper functions to replace the radix tree based
metaphors currently in use.  The biggest change is that converted code
doesn't see its own lock bit; get_unlocked_entry() always returns an
entry with the lock bit clear.  So we don't have to mess around loading
the current entry and clearing the lock bit; we can just store the
unlocked entry that we already have.

Signed-off-by: Matthew Wilcox <willy@infradead.org>
2018-10-21 10:46:43 -04:00
Matthew Wilcox
ec4907ff69 dax: Hash on XArray instead of mapping
Since the XArray is embedded in the struct address_space, its address
contains exactly as much entropy as the address of the mapping.  This
patch is purely preparatory for later patches which will simplify the
wait/wake interfaces.

Signed-off-by: Matthew Wilcox <willy@infradead.org>
2018-10-21 10:46:43 -04:00
Matthew Wilcox
a77d19f46a dax: Rename some functions
Remove mentions of 'radix' and 'radix tree'.  Simplify some names by
dropping the word 'mapping'.

Signed-off-by: Matthew Wilcox <willy@infradead.org>
2018-10-21 10:46:42 -04:00
Matthew Wilcox
3159f943aa xarray: Replace exceptional entries
Introduce xarray value entries and tagged pointers to replace radix
tree exceptional entries.  This is a slight change in encoding to allow
the use of an extra bit (we can now store BITS_PER_LONG - 1 bits in a
value entry).  It is also a change in emphasis; exceptional entries are
intimidating and different.  As the comment explains, you can choose
to store values or pointers in the xarray and they are both first-class
citizens.

Signed-off-by: Matthew Wilcox <willy@infradead.org>
Reviewed-by: Josef Bacik <jbacik@fb.com>
2018-09-29 22:47:49 -04:00
Matthew Wilcox
b90ca5cc32 filesystem-dax: Fix use of zero page
Use my_zero_pfn instead of ZERO_PAGE(), and pass the vaddr to it instead
of zero so it works on MIPS and s390 who reference the vaddr to select a
zero page.

Cc: <stable@vger.kernel.org>
Fixes: 91d25ba8a6 ("dax: use common 4k zero page for dax mmap reads")
Signed-off-by: Matthew Wilcox <willy@infradead.org>
Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2018-09-11 21:27:44 -07:00
Linus Torvalds
2923b27e54 libnvdimm-for-4.19_dax-memory-failure
* memory_failure() gets confused by dev_pagemap backed mappings. The
   recovery code has specific enabling for several possible page states
   that needs new enabling to handle poison in dax mappings. Teach
   memory_failure() about ZONE_DEVICE pages.
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Merge tag 'libnvdimm-for-4.19_dax-memory-failure' of gitolite.kernel.org:pub/scm/linux/kernel/git/nvdimm/nvdimm

Pull libnvdimm memory-failure update from Dave Jiang:
 "As it stands, memory_failure() gets thoroughly confused by dev_pagemap
  backed mappings. The recovery code has specific enabling for several
  possible page states and needs new enabling to handle poison in dax
  mappings.

  In order to support reliable reverse mapping of user space addresses:

   1/ Add new locking in the memory_failure() rmap path to prevent races
      that would typically be handled by the page lock.

   2/ Since dev_pagemap pages are hidden from the page allocator and the
      "compound page" accounting machinery, add a mechanism to determine
      the size of the mapping that encompasses a given poisoned pfn.

   3/ Given pmem errors can be repaired, change the speculatively
      accessed poison protection, mce_unmap_kpfn(), to be reversible and
      otherwise allow ongoing access from the kernel.

  A side effect of this enabling is that MADV_HWPOISON becomes usable
  for dax mappings, however the primary motivation is to allow the
  system to survive userspace consumption of hardware-poison via dax.
  Specifically the current behavior is:

     mce: Uncorrected hardware memory error in user-access at af34214200
     {1}[Hardware Error]: It has been corrected by h/w and requires no further action
     mce: [Hardware Error]: Machine check events logged
     {1}[Hardware Error]: event severity: corrected
     Memory failure: 0xaf34214: reserved kernel page still referenced by 1 users
     [..]
     Memory failure: 0xaf34214: recovery action for reserved kernel page: Failed
     mce: Memory error not recovered
     <reboot>

  ...and with these changes:

     Injecting memory failure for pfn 0x20cb00 at process virtual address 0x7f763dd00000
     Memory failure: 0x20cb00: Killing dax-pmd:5421 due to hardware memory corruption
     Memory failure: 0x20cb00: recovery action for dax page: Recovered

  Given all the cross dependencies I propose taking this through
  nvdimm.git with acks from Naoya, x86/core, x86/RAS, and of course dax
  folks"

* tag 'libnvdimm-for-4.19_dax-memory-failure' of gitolite.kernel.org:pub/scm/linux/kernel/git/nvdimm/nvdimm:
  libnvdimm, pmem: Restore page attributes when clearing errors
  x86/memory_failure: Introduce {set, clear}_mce_nospec()
  x86/mm/pat: Prepare {reserve, free}_memtype() for "decoy" addresses
  mm, memory_failure: Teach memory_failure() about dev_pagemap pages
  filesystem-dax: Introduce dax_lock_mapping_entry()
  mm, memory_failure: Collect mapping size in collect_procs()
  mm, madvise_inject_error: Let memory_failure() optionally take a page reference
  mm, dev_pagemap: Do not clear ->mapping on final put
  mm, madvise_inject_error: Disable MADV_SOFT_OFFLINE for ZONE_DEVICE pages
  filesystem-dax: Set page->index
  device-dax: Set page->index
  device-dax: Enable page_mapping()
  device-dax: Convert to vmf_insert_mixed and vm_fault_t
2018-08-25 18:43:59 -07:00
Linus Torvalds
828bf6e904 libnvdimm-for-4.19_misc
Collection of misc libnvdimm patches for 4.19 submission
 * Adding support to read locked nvdimm capacity.
 
 * Change test code to make DSM failure code injection an override.
 
 * Add support for calculate maximum contiguous area for namespace.
 
 * Add support for queueing a short ARS when there is on going ARS for
   nvdimm.
 
 * Allow NULL to be passed in to ->direct_access() for kaddr and
   pfn params.
 
 * Improve smart injection support for nvdimm emulation testing.
 
 * Fix test code that supports for emulating controller temperature.
 
 * Fix hang on error before devm_memremap_pages()
 
 * Fix a bug that causes user memory corruption when data returned
   to user for ars_status.
 
 * Maintainer updates for Ross Zwisler emails and adding Jan Kara to fsdax.
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Merge tag 'libnvdimm-for-4.19_misc' of gitolite.kernel.org:pub/scm/linux/kernel/git/nvdimm/nvdimm

Pull libnvdimm updates from Dave Jiang:
 "Collection of misc libnvdimm patches for 4.19 submission:

   - Adding support to read locked nvdimm capacity.

   - Change test code to make DSM failure code injection an override.

   - Add support for calculate maximum contiguous area for namespace.

   - Add support for queueing a short ARS when there is on going ARS for
     nvdimm.

   - Allow NULL to be passed in to ->direct_access() for kaddr and pfn
     params.

   - Improve smart injection support for nvdimm emulation testing.

   - Fix test code that supports for emulating controller temperature.

   - Fix hang on error before devm_memremap_pages()

   - Fix a bug that causes user memory corruption when data returned to
     user for ars_status.

   - Maintainer updates for Ross Zwisler emails and adding Jan Kara to
     fsdax"

* tag 'libnvdimm-for-4.19_misc' of gitolite.kernel.org:pub/scm/linux/kernel/git/nvdimm/nvdimm:
  libnvdimm: fix ars_status output length calculation
  device-dax: avoid hang on error before devm_memremap_pages()
  tools/testing/nvdimm: improve emulation of smart injection
  filesystem-dax: Do not request kaddr and pfn when not required
  md/dm-writecache: Don't request pointer dummy_addr when not required
  dax/super: Do not request a pointer kaddr when not required
  tools/testing/nvdimm: kaddr and pfn can be NULL to ->direct_access()
  s390, dcssblk: kaddr and pfn can be NULL to ->direct_access()
  libnvdimm, pmem: kaddr and pfn can be NULL to ->direct_access()
  acpi/nfit: queue issuing of ars when an uc error notification comes in
  libnvdimm: Export max available extent
  libnvdimm: Use max contiguous area for namespace size
  MAINTAINERS: Add Jan Kara for filesystem DAX
  MAINTAINERS: update Ross Zwisler's email address
  tools/testing/nvdimm: Fix support for emulating controller temperature
  tools/testing/nvdimm: Make DSM failure code injection an override
  acpi, nfit: Prefer _DSM over _LSR for namespace label reads
  libnvdimm: Introduce locked DIMM capacity support
2018-08-25 18:13:10 -07:00
Huaisheng Ye
86ed913b0e filesystem-dax: Do not request kaddr and pfn when not required
Some functions within fs/dax don't need to get local pointer kaddr
or variable pfn from direct_access. Using NULL instead of having to
pass in useless pointer or variable that caller then just throw away.

Signed-off-by: Huaisheng Ye <yehs1@lenovo.com>
Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
2018-07-30 09:40:42 -07:00
Ross Zwisler
cdbf8897cb dax: dax_layout_busy_page() warn on !exceptional
Inodes using DAX should only ever have exceptional entries in their page
caches.  Make this clear by warning if the iteration in
dax_layout_busy_page() ever sees a non-exceptional entry, and by adding a
comment for the pagevec_release() call which only deals with struct page
pointers.

Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>
2018-07-29 16:59:16 -04:00
Dan Williams
c2a7d2a115 filesystem-dax: Introduce dax_lock_mapping_entry()
In preparation for implementing support for memory poison (media error)
handling via dax mappings, implement a lock_page() equivalent. Poison
error handling requires rmap and needs guarantees that the page->mapping
association is maintained / valid (inode not freed) for the duration of
the lookup.

In the device-dax case it is sufficient to simply hold a dev_pagemap
reference. In the filesystem-dax case we need to use the entry lock.

Export the entry lock via dax_lock_mapping_entry() that uses
rcu_read_lock() to protect against the inode being freed, and
revalidates the page->mapping association under xa_lock().

Cc: Christoph Hellwig <hch@lst.de>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
2018-07-23 10:38:06 -07:00
Dan Williams
73449daf8f filesystem-dax: Set page->index
In support of enabling memory_failure() handling for filesystem-dax
mappings, set ->index to the pgoff of the page. The rmap implementation
requires ->index to bound the search through the vma interval tree. The
index is set and cleared at dax_associate_entry() and
dax_disassociate_entry() time respectively.

Cc: Christoph Hellwig <hch@lst.de>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
2018-07-20 11:21:15 -07:00
Linus Torvalds
7d3bf613e9 libnvdimm for 4.18
* DAX broke a fundamental assumption of truncate of file mapped pages.
   The truncate path assumed that it is safe to disconnect a pinned page
   from a file and let the filesystem reclaim the physical block. With DAX
   the page is equivalent to the filesystem block. Introduce
   dax_layout_busy_page() to enable filesystems to wait for pinned DAX
   pages to be released. Without this wait a filesystem could allocate
   blocks under active device-DMA to a new file.
 
 * DAX arranges for the block layer to be bypassed and uses
   dax_direct_access() + copy_to_iter() to satisfy read(2) calls.
   However, the memcpy_mcsafe() facility is available through the pmem
   block driver. In order to safely handle media errors, via the DAX
   block-layer bypass, introduce copy_to_iter_mcsafe().
 
 * Fix cache management policy relative to the ACPI NFIT Platform
   Capabilities Structure to properly elide cache flushes when they are not
   necessary. The table indicates whether CPU caches are power-fail
   protected. Clarify that a deep flush is always performed on
   REQ_{FUA,PREFLUSH} requests.
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Merge tag 'libnvdimm-for-4.18' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm

Pull libnvdimm updates from Dan Williams:
 "This adds a user for the new 'bytes-remaining' updates to
  memcpy_mcsafe() that you already received through Ingo via the
  x86-dax- for-linus pull.

  Not included here, but still targeting this cycle, is support for
  handling memory media errors (poison) consumed via userspace dax
  mappings.

  Summary:

   - DAX broke a fundamental assumption of truncate of file mapped
     pages. The truncate path assumed that it is safe to disconnect a
     pinned page from a file and let the filesystem reclaim the physical
     block. With DAX the page is equivalent to the filesystem block.
     Introduce dax_layout_busy_page() to enable filesystems to wait for
     pinned DAX pages to be released. Without this wait a filesystem
     could allocate blocks under active device-DMA to a new file.

   - DAX arranges for the block layer to be bypassed and uses
     dax_direct_access() + copy_to_iter() to satisfy read(2) calls.
     However, the memcpy_mcsafe() facility is available through the pmem
     block driver. In order to safely handle media errors, via the DAX
     block-layer bypass, introduce copy_to_iter_mcsafe().

   - Fix cache management policy relative to the ACPI NFIT Platform
     Capabilities Structure to properly elide cache flushes when they
     are not necessary. The table indicates whether CPU caches are
     power-fail protected. Clarify that a deep flush is always performed
     on REQ_{FUA,PREFLUSH} requests"

* tag 'libnvdimm-for-4.18' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm: (21 commits)
  dax: Use dax_write_cache* helpers
  libnvdimm, pmem: Do not flush power-fail protected CPU caches
  libnvdimm, pmem: Unconditionally deep flush on *sync
  libnvdimm, pmem: Complete REQ_FLUSH => REQ_PREFLUSH
  acpi, nfit: Remove ecc_unit_size
  dax: dax_insert_mapping_entry always succeeds
  libnvdimm, e820: Register all pmem resources
  libnvdimm: Debug probe times
  linvdimm, pmem: Preserve read-only setting for pmem devices
  x86, nfit_test: Add unit test for memcpy_mcsafe()
  pmem: Switch to copy_to_iter_mcsafe()
  dax: Report bytes remaining in dax_iomap_actor()
  dax: Introduce a ->copy_to_iter dax operation
  uio, lib: Fix CONFIG_ARCH_HAS_UACCESS_MCSAFE compilation
  xfs, dax: introduce xfs_break_dax_layouts()
  xfs: prepare xfs_break_layouts() for another layout type
  xfs: prepare xfs_break_layouts() to be called with XFS_MMAPLOCK_EXCL
  mm, fs, dax: handle layout changes to pinned dax mappings
  mm: fix __gup_device_huge vs unmap
  mm: introduce MEMORY_DEVICE_FS_DAX and CONFIG_DEV_PAGEMAP_OPS
  ...
2018-06-08 17:21:52 -07:00
Dan Williams
930218affe Merge branch 'for-4.18/mcsafe' into libnvdimm-for-next 2018-06-08 15:16:44 -07:00
Souptick Joarder
ab77dab462 fs/dax.c: use new return type vm_fault_t
Use new return type vm_fault_t for fault handler.  For now, this is just
documenting that the function returns a VM_FAULT value rather than an
errno.  Once all instances are converted, vm_fault_t will become a
distinct type.

commit 1c8f422059 ("mm: change return type to vm_fault_t")

There was an existing bug inside dax_load_hole() if vm_insert_mixed had
failed to allocate a page table, we'd return VM_FAULT_NOPAGE instead of
VM_FAULT_OOM.  With new vmf_insert_mixed() this issue is addressed.

vm_insert_mixed_mkwrite has inefficiency when it returns an error value,
driver has to convert it to vm_fault_t type.  With new
vmf_insert_mixed_mkwrite() this limitation will be addressed.

Link: http://lkml.kernel.org/r/20180510181121.GA15239@jordon-HP-15-Notebook-PC
Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Matthew Wilcox <mawilcox@microsoft.com>
Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-06-07 17:34:33 -07:00
Matthew Wilcox
cc4a90ac81 dax: dax_insert_mapping_entry always succeeds
It does not return an error, so we don't need to check the return value
for IS_ERR().  Indeed, it is a bug to do so; with a sufficiently large
PFN, a legitimate DAX entry may be mistaken for an error return.

Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2018-06-02 19:39:37 -07:00
Dan Williams
a77d478642 dax: Report bytes remaining in dax_iomap_actor()
In preparation for protecting the dax read(2) path from media errors
with copy_to_iter_mcsafe() (via dax_copy_to_iter()), convert the
implementation to report the bytes successfully transferred.

Cc: <x86@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2018-05-22 23:18:31 -07:00
Dan Williams
b3a9a0c36e dax: Introduce a ->copy_to_iter dax operation
Similar to the ->copy_from_iter() operation, a platform may want to
deploy an architecture or device specific routine for handling reads
from a dax_device like /dev/pmemX. On x86 this routine will point to a
machine check safe version of copy_to_iter(). For now, add the plumbing
to device-mapper and the dax core.

Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Mike Snitzer <snitzer@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2018-05-22 23:18:31 -07:00
Dan Williams
5fac7408d8 mm, fs, dax: handle layout changes to pinned dax mappings
Background:

get_user_pages() in the filesystem pins file backed memory pages for
access by devices performing dma. However, it only pins the memory pages
not the page-to-file offset association. If a file is truncated the
pages are mapped out of the file and dma may continue indefinitely into
a page that is owned by a device driver. This breaks coherency of the
file vs dma, but the assumption is that if userspace wants the
file-space truncated it does not matter what data is inbound from the
device, it is not relevant anymore. The only expectation is that dma can
safely continue while the filesystem reallocates the block(s).

Problem:

This expectation that dma can safely continue while the filesystem
changes the block map is broken by dax. With dax the target dma page
*is* the filesystem block. The model of leaving the page pinned for dma,
but truncating the file block out of the file, means that the filesytem
is free to reallocate a block under active dma to another file and now
the expected data-incoherency situation has turned into active
data-corruption.

Solution:

Defer all filesystem operations (fallocate(), truncate()) on a dax mode
file while any page/block in the file is under active dma. This solution
assumes that dma is transient. Cases where dma operations are known to
not be transient, like RDMA, have been explicitly disabled via
commits like 5f1d43de54 "IB/core: disable memory registration of
filesystem-dax vmas".

The dax_layout_busy_page() routine is called by filesystems with a lock
held against mm faults (i_mmap_lock) to find pinned / busy dax pages.
The process of looking up a busy page invalidates all mappings
to trigger any subsequent get_user_pages() to block on i_mmap_lock.
The filesystem continues to call dax_layout_busy_page() until it finally
returns no more active pages. This approach assumes that the page
pinning is transient, if that assumption is violated the system would
have likely hung from the uncompleted I/O.

Cc: Jeff Moyer <jmoyer@redhat.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: "Darrick J. Wong" <darrick.wong@oracle.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Reported-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2018-05-22 07:19:08 -07:00
Jonathan Corbet
24844fd339 Merge branch 'mm-rst' into docs-next
Mike Rapoport says:

  These patches convert files in Documentation/vm to ReST format, add an
  initial index and link it to the top level documentation.

  There are no contents changes in the documentation, except few spelling
  fixes. The relatively large diffstat stems from the indentation and
  paragraph wrapping changes.

  I've tried to keep the formatting as consistent as possible, but I could
  miss some places that needed markup and add some markup where it was not
  necessary.

[jc: significant conflicts in vm/hmm.rst]
2018-04-16 14:25:08 -06:00
Mike Rapoport
ad56b738c5 docs/vm: rename documentation files to .rst
Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2018-04-16 14:18:15 -06:00
Matthew Wilcox
b93b016313 page cache: use xa_lock
Remove the address_space ->tree_lock and use the xa_lock newly added to
the radix_tree_root.  Rename the address_space ->page_tree to ->i_pages,
since we don't really care that it's a tree.

[willy@infradead.org: fix nds32, fs/dax.c]
  Link: http://lkml.kernel.org/r/20180406145415.GB20605@bombadil.infradead.orgLink: http://lkml.kernel.org/r/20180313132639.17387-9-willy@infradead.org
Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com>
Acked-by: Jeff Layton <jlayton@redhat.com>
Cc: Darrick J. Wong <darrick.wong@oracle.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-04-11 10:28:39 -07:00
Dan Williams
d2c997c0f1 fs, dax: use page->mapping to warn if truncate collides with a busy page
Catch cases where extent unmap operations encounter pages that are
pinned / busy. Typically this is pinned pages that are under active dma.
This warning is a canary for potential data corruption as truncated
blocks could be allocated to a new file while the device is still
performing i/o.

Here is an example of a collision that this implementation catches:

 WARNING: CPU: 2 PID: 1286 at fs/dax.c:343 dax_disassociate_entry+0x55/0x80
 [..]
 Call Trace:
  __dax_invalidate_mapping_entry+0x6c/0xf0
  dax_delete_mapping_entry+0xf/0x20
  truncate_exceptional_pvec_entries.part.12+0x1af/0x200
  truncate_inode_pages_range+0x268/0x970
  ? tlb_gather_mmu+0x10/0x20
  ? up_write+0x1c/0x40
  ? unmap_mapping_range+0x73/0x140
  xfs_free_file_space+0x1b6/0x5b0 [xfs]
  ? xfs_file_fallocate+0x7f/0x320 [xfs]
  ? down_write_nested+0x40/0x70
  ? xfs_ilock+0x21d/0x2f0 [xfs]
  xfs_file_fallocate+0x162/0x320 [xfs]
  ? rcu_read_lock_sched_held+0x3f/0x70
  ? rcu_sync_lockdep_assert+0x2a/0x50
  ? __sb_start_write+0xd0/0x1b0
  ? vfs_fallocate+0x20c/0x270
  vfs_fallocate+0x154/0x270
  SyS_fallocate+0x43/0x80
  entry_SYSCALL_64_fastpath+0x1f/0x96

Cc: Jeff Moyer <jmoyer@redhat.com>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2018-04-03 05:41:19 -07:00
Dan Williams
3fe0791c29 dax: store pfns in the radix
In preparation for examining the busy state of dax pages in the truncate
path, switch from sectors to pfns in the radix.

Cc: Jeff Moyer <jmoyer@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2018-03-30 11:34:54 -07:00
Linus Torvalds
23aedc4b9b Only miscellaneous cleanups and bug fixes for ext4 this cycle.
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Merge tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4

Pull ext4 updates from Ted Ts'o:
 "Only miscellaneous cleanups and bug fixes for ext4 this cycle"

* tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4:
  ext4: create ext4_kset dynamically
  ext4: create ext4_feat kobject dynamically
  ext4: release kobject/kset even when init/register fail
  ext4: fix incorrect indentation of if statement
  ext4: correct documentation for grpid mount option
  ext4: use 'sbi' instead of 'EXT4_SB(sb)'
  ext4: save error to disk in __ext4_grp_locked_error()
  jbd2: fix sphinx kernel-doc build warnings
  ext4: fix a race in the ext4 shutdown path
  mbcache: make sure c_entry_count is not decremented past zero
  ext4: no need flush workqueue before destroying it
  ext4: fixed alignment and minor code cleanup in ext4.h
  ext4: fix ENOSPC handling in DAX page fault handler
  dax: pass detailed error code from dax_iomap_fault()
  mbcache: revert "fs/mbcache.c: make count_objects() more robust"
  mbcache: initialize entry->e_referenced in mb_cache_entry_create()
  ext4: fix up remaining files with SPDX cleanups
2018-02-03 13:49:22 -08:00
Matthew Wilcox
977fbdcd59 mm: add unmap_mapping_pages()
Several users of unmap_mapping_range() would prefer to express their
range in pages rather than bytes.  Unfortuately, on a 32-bit kernel, you
have to remember to cast your page number to a 64-bit type before
shifting it, and four places in the current tree didn't remember to do
that.  That's a sign of a bad interface.

Conveniently, unmap_mapping_range() actually converts from bytes into
pages, so hoist the guts of unmap_mapping_range() into a new function
unmap_mapping_pages() and convert the callers which want to use pages.

Link: http://lkml.kernel.org/r/20171206142627.GD32044@bombadil.infradead.org
Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com>
Reported-by: "zhangyi (F)" <yi.zhang@huawei.com>
Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-01-31 17:18:37 -08:00
Jan H. Schönherr
ee190ca651 fs/dax.c: release PMD lock even when there is no PMD support in DAX
follow_pte_pmd() can theoretically return after having acquired a PMD
lock, even when DAX was not compiled with CONFIG_FS_DAX_PMD.

Release the PMD lock unconditionally.

Link: http://lkml.kernel.org/r/20180118133839.20587-1-jschoenh@amazon.de
Fixes: f729c8c9b2 ("dax: wrprotect pmd_t in dax_mapping_entry_mkclean")
Signed-off-by: Jan H. Schönherr <jschoenh@amazon.de>
Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-01-31 17:18:34 -08:00