With new refcounting we will be able map the same compound page with
PTEs and PMDs.  It requires adjustment to conditions when we can reuse
the page on write-protection fault.

For PTE fault we can't reuse the page if it's part of huge page.

For PMD we can only reuse the page if nobody else maps the huge page or
it's part.  We can do it by checking page_mapcount() on each sub-page,
but it's expensive.

The cheaper way is to check page_count() to be equal 1: every mapcount
takes page reference, so this way we can guarantee, that the PMD is the
only mapping.

This approach can give false negative if somebody pinned the page, but
that doesn't affect correctness.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Tested-by: Sasha Levin <sasha.levin@oracle.com>
Tested-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Acked-by: Jerome Marchand <jmarchan@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Steve Capper <steve.capper@linaro.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

As with rmap, with new refcounting we cannot rely on PageTransHuge() to
check if we need to charge size of huge page form the cgroup.  We need
to get information from caller to know whether it was mapped with PMD or
PTE.

We do uncharge when last reference on the page gone.  At that point if
we see PageTransHuge() it means we need to unchange whole huge page.

The tricky part is partial unmap -- when we try to unmap part of huge
page.  We don't do a special handing of this situation, meaning we don't
uncharge the part of huge page unless last user is gone or
split_huge_page() is triggered.  In case of cgroup memory pressure
happens the partial unmapped page will be split through shrinker.  This
should be good enough.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Tested-by: Sasha Levin <sasha.levin@oracle.com>
Tested-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Jerome Marchand <jmarchan@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Steve Capper <steve.capper@linaro.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

We're going to allow mapping of individual 4k pages of THP compound
page.  It means we cannot rely on PageTransHuge() check to decide if
map/unmap small page or THP.

The patch adds new argument to rmap functions to indicate whether we
want to operate on whole compound page or only the small page.

[n-horiguchi@ah.jp.nec.com: fix mapcount mismatch in hugepage migration]
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Tested-by: Sasha Levin <sasha.levin@oracle.com>
Tested-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Jerome Marchand <jmarchan@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Steve Capper <steve.capper@linaro.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

The goal of this patchset is to make refcounting on THP pages cheaper
with simpler semantics and allow the same THP compound page to be mapped
with PMD and PTEs.  This is required to get reasonable THP-pagecache
implementation.

With the new refcounting design it's much easier to protect against
split_huge_page(): simple reference on a page will make you the deal.
It makes gup_fast() implementation simpler and doesn't require
special-case in futex code to handle tail THP pages.

It should improve THP utilization over the system since splitting THP in
one process doesn't necessary lead to splitting the page in all other
processes have the page mapped.

The patchset drastically lower complexity of get_page()/put_page()
codepaths.  I encourage people look on this code before-and-after to
justify time budget on reviewing this patchset.

This patch (of 37):

With new refcounting all subpages of the compound page are not necessary
have the same mapcount.  We need to take into account mapcount of every
sub-page.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Tested-by: Sasha Levin <sasha.levin@oracle.com>
Tested-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Acked-by: Jerome Marchand <jmarchan@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Steve Capper <steve.capper@linaro.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Nobody uses them.
Signed-off-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>

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>
Reviewed-by: Jérôme Glisse <jglisse@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Christoph Lameter <cl@linux.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Steve Capper <steve.capper@linaro.org>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Jerome Marchand <jmarchan@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

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>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Christoph Lameter <cl@linux.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Steve Capper <steve.capper@linaro.org>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Jerome Marchand <jmarchan@redhat.com>
Cc: Jérôme Glisse <jglisse@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

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>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Christoph Lameter <cl@linux.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Steve Capper <steve.capper@linaro.org>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Jerome Marchand <jmarchan@redhat.com>
Cc: Jérôme Glisse <jglisse@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

So far, only IA64 uses PG_uncached and only on non-compound pages.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Christoph Lameter <cl@linux.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Steve Capper <steve.capper@linaro.org>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Jerome Marchand <jmarchan@redhat.com>
Cc: Jérôme Glisse <jglisse@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Transparent huge pages can be mlocked -- whole compund page at once.
Something went wrong if we're trying to mlock() tail page.  Let's use
PF_NO_TAIL.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Christoph Lameter <cl@linux.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Steve Capper <steve.capper@linaro.org>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Jerome Marchand <jmarchan@redhat.com>
Cc: Jérôme Glisse <jglisse@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

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>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Christoph Lameter <cl@linux.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Steve Capper <steve.capper@linaro.org>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Jerome Marchand <jmarchan@redhat.com>
Cc: Jérôme Glisse <jglisse@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

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>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Christoph Lameter <cl@linux.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Steve Capper <steve.capper@linaro.org>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Jerome Marchand <jmarchan@redhat.com>
Cc: Jérôme Glisse <jglisse@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

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>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Christoph Lameter <cl@linux.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Steve Capper <steve.capper@linaro.org>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Jerome Marchand <jmarchan@redhat.com>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: Hillf Danton <hillf.zj@alibaba-inc.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

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>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Christoph Lameter <cl@linux.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Steve Capper <steve.capper@linaro.org>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Jerome Marchand <jmarchan@redhat.com>
Cc: Jérôme Glisse <jglisse@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

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>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Christoph Lameter <cl@linux.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Steve Capper <steve.capper@linaro.org>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Jerome Marchand <jmarchan@redhat.com>
Cc: Jérôme Glisse <jglisse@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

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>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Christoph Lameter <cl@linux.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Steve Capper <steve.capper@linaro.org>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Jerome Marchand <jmarchan@redhat.com>
Cc: Jérôme Glisse <jglisse@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

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>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Christoph Lameter <cl@linux.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Steve Capper <steve.capper@linaro.org>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Jerome Marchand <jmarchan@redhat.com>
Cc: Jérôme Glisse <jglisse@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

lock_page() must operate on the whole compound page.  It doesn't make
much sense to lock part of compound page.  Change code to use head
page's PG_locked, if tail page is passed.

This patch also gets rid of custom helper functions --
__set_page_locked() and __clear_page_locked().  They are replaced with
helpers generated by __SETPAGEFLAG/__CLEARPAGEFLAG.  Tail pages to these
helper would trigger VM_BUG_ON().

SLUB uses PG_locked as a bit spin locked.  IIUC, tail pages should never
appear there.  VM_BUG_ON() is added to make sure that this assumption is
correct.

[akpm@linux-foundation.org: fix fs/cifs/file.c]
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Christoph Lameter <cl@linux.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Steve Capper <steve.capper@linaro.org>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Jerome Marchand <jmarchan@redhat.com>
Cc: Jérôme Glisse <jglisse@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

This patch adds a third argument to macros which create function
definitions for page flags.  This argument defines how page-flags
helpers behave on compound functions.

For now we define four policies:

 - PF_ANY: the helper function operates on the page it gets, regardless
   if it's non-compound, head or tail.

 - PF_HEAD: the helper function operates on the head page of the
   compound page if it gets tail page.

 - PF_NO_TAIL: only head and non-compond pages are acceptable for this
   helper function.

 - PF_NO_COMPOUND: only non-compound pages are acceptable for this
   helper function.

For now we use policy PF_ANY for all helpers, which matches current
behaviour.

We do not enforce the policy for TESTPAGEFLAG, because we have flags
checked for random pages all over the kernel.  Noticeable exception to
this is PageTransHuge() which triggers VM_BUG_ON() for tail page.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Christoph Lameter <cl@linux.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Steve Capper <steve.capper@linaro.org>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Jerome Marchand <jmarchan@redhat.com>
Cc: Jérôme Glisse <jglisse@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

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>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Christoph Lameter <cl@linux.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Steve Capper <steve.capper@linaro.org>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Jerome Marchand <jmarchan@redhat.com>
Cc: Jérôme Glisse <jglisse@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Use TESTPAGEFLAG_FALSE() to get it a bit cleaner.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Christoph Lameter <cl@linux.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Steve Capper <steve.capper@linaro.org>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Jerome Marchand <jmarchan@redhat.com>
Cc: Jérôme Glisse <jglisse@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull networking fixes from David Miller:
 "A quick set of bug fixes after there initial networking merge:

  1) Netlink multicast group storage allocator only was tested with
     nr_groups equal to 1, make it work for other values too.  From
     Matti Vaittinen.

  2) Check build_skb() return value in macb and hip04_eth drivers, from
     Weidong Wang.

  3) Don't leak x25_asy on x25_asy_open() failure.

  4) More DMA map/unmap fixes in 3c59x from Neil Horman.

  5) Don't clobber IP skb control block during GSO segmentation, from
     Konstantin Khlebnikov.

  6) ECN helpers for ipv6 don't fixup the checksum, from Eric Dumazet.

  7) Fix SKB segment utilization estimation in xen-netback, from David
     Vrabel.

  8) Fix lockdep splat in bridge addrlist handling, from Nikolay
     Aleksandrov"

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (26 commits)
  bgmac: Fix reversed test of build_skb() return value.
  bridge: fix lockdep addr_list_lock false positive splat
  net: smsc: Add support h8300
  xen-netback: free queues after freeing the net device
  xen-netback: delete NAPI instance when queue fails to initialize
  xen-netback: use skb to determine number of required guest Rx requests
  net: sctp: Move sequence start handling into sctp_transport_get_idx()
  ipv6: update skb->csum when CE mark is propagated
  net: phy: turn carrier off on phy attach
  net: macb: clear interrupts when disabling them
  sctp: support to lookup with ep+paddr in transport rhashtable
  net: hns: fixes no syscon error when init mdio
  dts: hisi: fixes no syscon fault when init mdio
  net: preserve IP control block during GSO segmentation
  fsl/fman: Delete one function call "put_device" in dtsec_config()
  hip04_eth: fix missing error handle for build_skb failed
  3c59x: fix another page map/single unmap imbalance
  3c59x: balance page maps and unmaps
  x25_asy: Free x25_asy on x25_asy_open() failure.
  mlxsw: fix SWITCHDEV_OBJ_ID_PORT_MDB
  ...

Pull sparc fixes from David Miller:
 "Two sparc bug fixes"

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc:
  sparc64: Fix numa node distance initialization
  sparc64: fix incorrect sign extension in sys_sparc64_personality

Pull powerpc updates from Michael Ellerman:
 "Core:
   - Ground work for the new Power9 MMU from Aneesh Kumar K.V
   - Optimise FP/VMX/VSX context switching from Anton Blanchard

  Misc:
   - Various cleanups from Krzysztof Kozlowski, John Ogness, Rashmica
     Gupta, Russell Currey, Gavin Shan, Daniel Axtens, Michael Neuling,
     Andrew Donnellan
   - Allow wrapper to work on non-english system from Laurent Vivier
   - Add rN aliases to the pt_regs_offset table from Rashmica Gupta
   - Fix module autoload for rackmeter & axonram drivers from Luis de
     Bethencourt
   - Include KVM guest test in all interrupt vectors from Paul Mackerras
   - Fix DSCR inheritance over fork() from Anton Blanchard
   - Make value-returning atomics & {cmp}xchg* & their atomic_ versions
     fully ordered from Boqun Feng
   - Print MSR TM bits in oops messages from Michael Neuling
   - Add TM signal return & invalid stack selftests from Michael Neuling
   - Limit EPOW reset event warnings from Vipin K Parashar
   - Remove the Cell QPACE code from Rashmica Gupta
   - Append linux_banner to exception information in xmon from Rashmica
     Gupta
   - Add selftest to check if VSRs are corrupted from Rashmica Gupta
   - Remove broken GregorianDay() from Daniel Axtens
   - Import Anton's context_switch2 benchmark into selftests from
     Michael Ellerman
   - Add selftest script to test HMI functionality from Daniel Axtens
   - Remove obsolete OPAL v2 support from Stewart Smith
   - Make enter_rtas() private from Michael Ellerman
   - PPR exception cleanups from Michael Ellerman
   - Add page soft dirty tracking from Laurent Dufour
   - Add support for Nvlink NPUs from Alistair Popple
   - Add support for kexec on 476fpe from Alistair Popple
   - Enable kernel CPU dlpar from sysfs from Nathan Fontenot
   - Copy only required pieces of the mm_context_t to the paca from
     Michael Neuling
   - Add a kmsg_dumper that flushes OPAL console output on panic from
     Russell Currey
   - Implement save_stack_trace_regs() to enable kprobe stack tracing
     from Steven Rostedt
   - Add HWCAP bits for Power9 from Michael Ellerman
   - Fix _PAGE_PTE breaking swapoff from Aneesh Kumar K.V
   - Fix _PAGE_SWP_SOFT_DIRTY breaking swapoff from Hugh Dickins
   - scripts/recordmcount.pl: support data in text section on powerpc
     from Ulrich Weigand
   - Handle R_PPC64_ENTRY relocations in modules from Ulrich Weigand

  cxl:
   - cxl: Fix possible idr warning when contexts are released from
     Vaibhav Jain
   - cxl: use correct operator when writing pcie config space values
     from Andrew Donnellan
   - cxl: Fix DSI misses when the context owning task exits from Vaibhav
     Jain
   - cxl: fix build for GCC 4.6.x from Brian Norris
   - cxl: use -Werror only with CONFIG_PPC_WERROR from Brian Norris
   - cxl: Enable PCI device ID for future IBM CXL adapter from Uma
     Krishnan

  Freescale:
   - Freescale updates from Scott: Highlights include moving QE code out
     of arch/powerpc (to be shared with arm), device tree updates, and
     minor fixes"

* tag 'powerpc-4.5-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (149 commits)
  powerpc/module: Handle R_PPC64_ENTRY relocations
  scripts/recordmcount.pl: support data in text section on powerpc
  powerpc/powernv: Fix OPAL_CONSOLE_FLUSH prototype and usages
  powerpc/mm: fix _PAGE_SWP_SOFT_DIRTY breaking swapoff
  powerpc/mm: Fix _PAGE_PTE breaking swapoff
  cxl: Enable PCI device ID for future IBM CXL adapter
  cxl: use -Werror only with CONFIG_PPC_WERROR
  cxl: fix build for GCC 4.6.x
  powerpc: Add HWCAP bits for Power9
  powerpc/powernv: Reserve PE#0 on NPU
  powerpc/powernv: Change NPU PE# assignment
  powerpc/powernv: Fix update of NVLink DMA mask
  powerpc/powernv: Remove misleading comment in pci.c
  powerpc: Implement save_stack_trace_regs() to enable kprobe stack tracing
  powerpc: Fix build break due to paca mm_context_t changes
  cxl: Fix DSI misses when the context owning task exits
  MAINTAINERS: Update Scott Wood's e-mail address
  powerpc/powernv: Fix minor off-by-one error in opal_mce_check_early_recovery()
  powerpc: Fix style of self-test config prompts
  powerpc/powernv: Only delay opal_rtc_read() retry when necessary
  ...

Fixes: f1640c3d ("bgmac: fix a missing check for build_skb")
Signed-off-by: David S. Miller <davem@davemloft.net>

Pull VFIO updates from Alex Williamson:

 - Fixes in AMD xgbe reset, spapr structure padding, type 1 flags (Dan
   Carpenter, Alexey Kardashevskiy, Pierre Morel)

 - Re-introduce no-iommu mode, with a user this time (Alex Williamson)

* tag 'vfio-v4.5-rc1' of git://github.com/awilliam/linux-vfio:
  vfio/iommu_type1: make use of info.flags
  vfio: Include No-IOMMU mode
  vfio: Add explicit alignments in vfio_iommu_spapr_tce_create
  VFIO: platform: reset: fix a warning message condition

Pull nfsd updates from Bruce Fields:
 "Smaller bugfixes and cleanup, including a fix for a failures of
  kerberized NFSv4.1 mounts, and Scott Mayhew's work addressing ACK
  storms that can affect some high-availability NFS setups"

* tag 'nfsd-4.5' of git://linux-nfs.org/~bfields/linux:
  nfsd: add new io class tracepoint
  nfsd: give up on CB_LAYOUTRECALLs after two lease periods
  nfsd: Fix nfsd leaks sunrpc module references
  lockd: constify nlmsvc_binding structure
  lockd: use to_delayed_work
  nfsd: use to_delayed_work
  Revert "svcrdma: Do not send XDR roundup bytes for a write chunk"
  lockd: Register callbacks on the inetaddr_chain and inet6addr_chain
  nfsd: Register callbacks on the inetaddr_chain and inet6addr_chain
  sunrpc: Add a function to close temporary transports immediately
  nfsd: don't base cl_cb_status on stale information
  nfsd4: fix gss-proxy 4.1 mounts for some AD principals
  nfsd: fix unlikely NULL deref in mach_creds_match
  nfsd: minor consolidation of mach_cred handling code
  nfsd: helper for dup of possibly NULL string
  svcrpc: move some initialization to common code
  nfsd: fix a warning message
  nfsd: constify nfsd4_callback_ops structure
  nfsd: recover: constify nfsd4_client_tracking_ops structures
  svcrdma: Do not send XDR roundup bytes for a write chunk

Pull vfs regression fix from Al Viro:
 "Fix for braino introduced in vfs.git#work.misc"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  amdkfd: Copy from the proper user command pointer

After promisc mode management was introduced a bridge device could do
dev_set_promiscuity from its ndo_change_rx_flags() callback which in
turn can be called after the bridge's addr_list_lock has been taken
(e.g. by dev_uc_add). This causes a false positive lockdep splat because
the port interfaces' addr_list_lock is taken when br_manage_promisc()
runs after the bridge's addr list lock was already taken.
To remove the false positive introduce a custom bridge addr_list_lock
class and set it on bridge init.
A simple way to reproduce this is with the following:
$ brctl addbr br0
$ ip l add l br0 br0.100 type vlan id 100
$ ip l set br0 up
$ ip l set br0.100 up
$ echo 1 > /sys/class/net/br0/bridge/vlan_filtering
$ brctl addif br0 eth0
Splat:
[   43.684325] =============================================
[   43.684485] [ INFO: possible recursive locking detected ]
[   43.684636] 4.4.0-rc8+ #54 Not tainted
[   43.684755] ---------------------------------------------
[   43.684906] brctl/1187 is trying to acquire lock:
[   43.685047]  (_xmit_ETHER){+.....}, at: [<ffffffff8150169e>] dev_set_rx_mode+0x1e/0x40
[   43.685460]  but task is already holding lock:
[   43.685618]  (_xmit_ETHER){+.....}, at: [<ffffffff815072a7>] dev_uc_add+0x27/0x80
[   43.686015]  other info that might help us debug this:
[   43.686316]  Possible unsafe locking scenario:

[   43.686743]        CPU0
[   43.686967]        ----
[   43.687197]   lock(_xmit_ETHER);
[   43.687544]   lock(_xmit_ETHER);
[   43.687886] *** DEADLOCK ***

[   43.688438]  May be due to missing lock nesting notation

[   43.688882] 2 locks held by brctl/1187:
[   43.689134]  #0:  (rtnl_mutex){+.+.+.}, at: [<ffffffff81510317>] rtnl_lock+0x17/0x20
[   43.689852]  #1:  (_xmit_ETHER){+.....}, at: [<ffffffff815072a7>] dev_uc_add+0x27/0x80
[   43.690575] stack backtrace:
[   43.690970] CPU: 0 PID: 1187 Comm: brctl Not tainted 4.4.0-rc8+ #54
[   43.691270] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.8.1-20150318_183358- 04/01/2014
[   43.691770]  ffffffff826a25c0 ffff8800369fb8e0 ffffffff81360ceb ffffffff826a25c0
[   43.692425]  ffff8800369fb9b8 ffffffff810d0466 ffff8800369fb968 ffffffff81537139
[   43.693071]  ffff88003a08c880 0000000000000000 00000000ffffffff 0000000002080020
[   43.693709] Call Trace:
[   43.693931]  [<ffffffff81360ceb>] dump_stack+0x4b/0x70
[   43.694199]  [<ffffffff810d0466>] __lock_acquire+0x1e46/0x1e90
[   43.694483]  [<ffffffff81537139>] ? netlink_broadcast_filtered+0x139/0x3e0
[   43.694789]  [<ffffffff8153b5da>] ? nlmsg_notify+0x5a/0xc0
[   43.695064]  [<ffffffff810d10f5>] lock_acquire+0xe5/0x1f0
[   43.695340]  [<ffffffff8150169e>] ? dev_set_rx_mode+0x1e/0x40
[   43.695623]  [<ffffffff815edea5>] _raw_spin_lock_bh+0x45/0x80
[   43.695901]  [<ffffffff8150169e>] ? dev_set_rx_mode+0x1e/0x40
[   43.696180]  [<ffffffff8150169e>] dev_set_rx_mode+0x1e/0x40
[   43.696460]  [<ffffffff8150189c>] dev_set_promiscuity+0x3c/0x50
[   43.696750]  [<ffffffffa0586845>] br_port_set_promisc+0x25/0x50 [bridge]
[   43.697052]  [<ffffffffa05869aa>] br_manage_promisc+0x8a/0xe0 [bridge]
[   43.697348]  [<ffffffffa05826ee>] br_dev_change_rx_flags+0x1e/0x20 [bridge]
[   43.697655]  [<ffffffff81501532>] __dev_set_promiscuity+0x132/0x1f0
[   43.697943]  [<ffffffff81501672>] __dev_set_rx_mode+0x82/0x90
[   43.698223]  [<ffffffff815072de>] dev_uc_add+0x5e/0x80
[   43.698498]  [<ffffffffa05b3c62>] vlan_device_event+0x542/0x650 [8021q]
[   43.698798]  [<ffffffff8109886d>] notifier_call_chain+0x5d/0x80
[   43.699083]  [<ffffffff810988b6>] raw_notifier_call_chain+0x16/0x20
[   43.699374]  [<ffffffff814f456e>] call_netdevice_notifiers_info+0x6e/0x80
[   43.699678]  [<ffffffff814f4596>] call_netdevice_notifiers+0x16/0x20
[   43.699973]  [<ffffffffa05872be>] br_add_if+0x47e/0x4c0 [bridge]
[   43.700259]  [<ffffffffa058801e>] add_del_if+0x6e/0x80 [bridge]
[   43.700548]  [<ffffffffa0588b5f>] br_dev_ioctl+0xaf/0xc0 [bridge]
[   43.700836]  [<ffffffff8151a7ac>] dev_ifsioc+0x30c/0x3c0
[   43.701106]  [<ffffffff8151aac9>] dev_ioctl+0xf9/0x6f0
[   43.701379]  [<ffffffff81254345>] ? mntput_no_expire+0x5/0x450
[   43.701665]  [<ffffffff812543ee>] ? mntput_no_expire+0xae/0x450
[   43.701947]  [<ffffffff814d7b02>] sock_do_ioctl+0x42/0x50
[   43.702219]  [<ffffffff814d8175>] sock_ioctl+0x1e5/0x290
[   43.702500]  [<ffffffff81242d0b>] do_vfs_ioctl+0x2cb/0x5c0
[   43.702771]  [<ffffffff81243079>] SyS_ioctl+0x79/0x90
[   43.703033]  [<ffffffff815eebb6>] entry_SYSCALL_64_fastpath+0x16/0x7a

CC: Vlad Yasevich <vyasevic@redhat.com>
CC: Stephen Hemminger <stephen@networkplumber.org>
CC: Bridge list <bridge@lists.linux-foundation.org>
CC: Andy Gospodarek <gospo@cumulusnetworks.com>
CC: Roopa Prabhu <roopa@cumulusnetworks.com>
Fixes: 2796d0c6 ("bridge: Automatically manage port promiscuous mode.")
Reported-by: Andy Gospodarek <gospo@cumulusnetworks.com>
Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Pull md updates from Neil Brown:
 "Mostly clustered-raid1 and raid5 journal updates.  one Y2038 fix and
  other minor stuff.

  One patch removes me from the MAINTAINERS file and adds a record of my
  md maintainership to Credits"

Many thanks to Neil, who has been around for a _looong_ time.

* tag 'md/4.5' of git://neil.brown.name/md: (26 commits)
  md/raid: only permit hot-add of compatible integrity profiles
  Remove myself as MD Maintainer, and add to Credits.
  raid5-cache: handle journal hotadd in quiesce
  MD: add journal with array suspended
  md: set MD_HAS_JOURNAL in correct places
  md: Remove 'ready' field from mddev.
  md: remove unnecesary md_new_event_inintr
  raid5: allow r5l_io_unit allocations to fail
  raid5-cache: use a mempool for the metadata block
  raid5-cache: use a bio_set
  raid5-cache: add journal hot add/remove support
  drivers: md: use ktime_get_real_seconds()
  md: avoid warning for 32-bit sector_t
  raid5-cache: free meta_page earlier
  raid5-cache: simplify r5l_move_io_unit_list
  md: update comment for md_allow_write
  md-cluster: update comments for MD_CLUSTER_SEND_LOCKED_ALREADY
  md-cluster: Protect communication with mutexes
  md-cluster: Defer MD reloading to mddev->thread
  md-cluster: update the documentation
  ...

Pull regulator updates from Mark Brown:
 "Aside from a fix for a spurious warning (which caused more problems
  than it fixed in the fixing really) this is all driver updates,
  including new drivers for Dialog PV88060/90 and TI LM363x and TPS65086
  devices.  The qcom_smd driver has had PM8916 and PMA8084 support
  added"

* tag 'regulator-v4.5' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/regulator: (36 commits)
  regulator: core: remove some dead code
  regulator: core: use dev_to_rdev
  regulator: lp872x: Get rid of duplicate reference to DVS GPIO
  regulator: lp872x: Add missing of_match in regulators descriptions
  regulator: axp20x: Fix GPIO LDO enable value for AXP22x
  regulator: lp8788: constify regulator_ops structures
  regulator: wm8*: constify regulator_ops structures
  regulator: da9*: constify regulator_ops structures
  regulator: mt6311: Use REGCACHE_RBTREE
  regulator: tps65917/palmas: Add bypass ops for LDOs with bypass capability
  regulator: qcom-smd: Add support for PMA8084
  regulator: qcom-smd: Add PM8916 support
  soc: qcom: documentation: Update SMD/RPM Docs
  regulator: pv88090: logical vs bitwise AND typo
  regulator: pv88090: Fix irq leak
  regulator: pv88090: new regulator driver
  regulator: wm831x-ldo: Use platform_register/unregister_drivers()
  regulator: wm831x-dcdc: Use platform_register/unregister_drivers()
  regulator: lp8788-ldo: Use platform_register/unregister_drivers()
  regulator: core: Fix nested locking of supplies
  ...

Add H8/300 platform support for smc91x
Signed-off-by: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: David S. Miller <davem@davemloft.net>

8f1d57c1 ("amdkfd: don't open-code memdup_user()") mistakenly uses
an uninitialized local pointer, gcc complains:

  drivers/gpu/drm/amd/amdkfd/kfd_chardev.c: In function ‘kfd_ioctl_dbg_address_watch’:
  drivers/gpu/drm/amd/amdkfd/kfd_chardev.c:562:12: warning: ‘args_buff’ may be used uninitialized in this function [-Wmaybe-uninitialized]
    args_buff = memdup_user(args_buff,
                ^

Fix it.
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Pull mailbox fixlet from Jussi Brar.

* 'mailbox-for-next' of git://git.linaro.org/landing-teams/working/fujitsu/integration:
  mailbox: constify mbox_chan_ops structure

David Vrabel says:

====================
xen-netback: use skb to determine number of required (etc.)

"xen-netback: use skb to determine number of required" plus two other
minor fixes I found down the back of the sofa.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

If a queue still has a NAPI instance added to the net device, freeing
the queues early results in a use-after-free.

The shouldn't ever happen because we disconnect and tear down all queues
before freeing the net device, but doing this makes it obviously safe.
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

When xenvif_connect() fails it may leave a stale NAPI instance added to
the device.  Make sure we delete it in the error path.
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Using the MTU or GSO size to determine the number of required guest Rx
requests for an skb was subtly broken since these value may change at
runtime.

After 1650d545 (xen-netback: always
fully coalesce guest Rx packets) we always fully pack a packet into
its guest Rx slots.  Calculating the number of required slots from the
packet length is then easy.
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/sctp/proc.c: In function ‘sctp_transport_get_idx’:
net/sctp/proc.c:313: warning: ‘obj’ may be used uninitialized in this function

This is currently a false positive, as all callers check for a zero
offset first, and handle this case in the exact same way.

Move the check and handling into sctp_transport_get_idx() to kill the
compiler warning, and avoid future bugs.
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

When a tunnel decapsulates the outer header, it has to comply
with RFC 6080 and eventually propagate CE mark into inner header.

It turns out IP6_ECN_set_ce() does not correctly update skb->csum
for CHECKSUM_COMPLETE packets, triggering infamous "hw csum failure"
messages and stack traces.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>