ARM: mm: use pteval_t to represent page protection values

When updating the page protection map after calculating the user_pgprot
value, the base protection map is temporarily stored in an unsigned long
type, causing truncation of the protection bits when LPAE is enabled.
This effectively means that calls to mprotect() will corrupt the upper
page attributes, clearing the XN bit unconditionally.

This patch uses pteval_t to store the intermediate protection values,
preserving the upper bits for 64-bit descriptors.
ARM: missing ->mmap_sem around find_vma() in swp_emulate.c

find_vma() is *not* safe when somebody else is removing vmas.  Not just
the return value might get bogus just as you are getting it (this instance
doesn't try to dereference the resulting vma), the search itself can get
buggered in rather spectacular ways.  IOW, ->mmap_sem really, really is
not optional here.
mm: Fix PageHead when [NOT]CONFIG_PAGEFLAGS_EXTENDED #

(PageHead) is true, for tail pages.  If this is indeed the intended
behavior, which I doubt because it breaks cache cleaning on some ARM
systems, then the nomenclature is highly problematic.

This patch makes sure PageHead is only true for head pages and PageTail
is only true for tail pages, and neither is true for non-compound pages.

[ This buglet seems ancient - seems to have been introduced back in Apr
  2008 in commit 6a1e7f7: 'pageflags: convert to the use of new macros'.  And the reason nobody noticed is because the PageHead() tests are almost all about just sanity-checking, and only used on
  pages that are actual page heads.  The fact that the old code returned
  true for tail pages too was thus not really noticeable.   - Linus ]
mm: dmapool: use provided gfp flags for all dma_alloc_coherent() calls

dmapool always calls dma_alloc_coherent() with GFP_ATOMIC flag,
regardless the flags provided by the caller. This causes excessive
pruning of emergency memory pools without any good reason. Additionaly,
on ARM architecture any driver which is using dmapools will sooner or
later  trigger the following error:
'ERROR: 256 KiB atomic DMA coherent pool is too small! Please increase it with coherent_pool= kernel parameter!'. Increasing the coherent pool size usually doesn't help much and only delays such error, because all GFP_ATOMIC DMA allocations are always served from the special, very limited memory pool.

This patch changes the dmapool code to correctly use gfp flags provided
by the dmapool caller.
mm/vmemmap: fix wrong use of virt_to_page
mm: soft offline: split thp at the beginning of soft_offline_page()

When we try to soft-offline a thp tail page, put_page() is called on the
tail page unthinkingly and VM_BUG_ON is triggered in put_compound_page().

This patch splits thp before going into the main body of soft-offlining.
mm: bugfix: set current->reclaim_state to NULL while returning from kswapd()

In kswapd(), set current->reclaim_state to NULL before returning, as
current->reclaim_state holds reference to variable on kswapd()'s stack.

In rare cases, while returning from kswapd() during memory offlining,
__free_slab() and freepages() can access the dangling pointer of
current->reclaim_state.
mm: compaction: fix echo 1 > compact_memory return error issue

This tells system return 3(COMPACT_COMPLETE) after write data to
compact_memory.

The fix is to make the system just return 0 instead 3(COMPACT_COMPLETE)
from sysctl_compaction_handler after compaction_nodes finished.
ext4: do not try to write superblock on ro remount w/o journal

When a journal-less ext4 filesystem is mounted on a read-only block
device (blockdev --setro will do), each remount (for other, unrelated,
flags, like suid=>nosuid etc) results in a series of scary messages
from kernel telling about I/O errors on the device.

This is becauese of the following code ext4_remount():

       if (sbi->s_journal == NULL)
                ext4_commit_super(sb, 1);

at the end of remount procedure, which forces writing (flushing) of
a superblock regardless whenever it is dirty or not, if the filesystem
is readonly or not, and whenever the device itself is readonly or not.

We only need call ext4_commit_super when the file system had been
previously mounted read/write.

Thanks to Eric Sandeen for help in diagnosing this issue.
regulator: Correct voltage value used in regulator_set_voltage_complete

The voltage value specified in the tracepoint function
trace_regulator_set_voltage_complete() inside of the function
_regulator_do_set_voltage() is erroneously set to -1 if a
list_voltage() callback is not specified by a regulator device
even if a get_voltage() callback is present.

Add a check for the get_voltage() callback function and call it
in order to determine the voltage that was chosen from the min_uV
to max_uV range.