mm/page_alloc.c: fix watermark check in __zone_watermark_ok()

The watermark check consists of two sub-checks.  The first one is:

	if (free_pages <= min + lowmem_reserve)
		return false;

The check assures that there is minimal amount of RAM in the zone.  If
CMA is used then the free_pages is reduced by the number of free pages
in CMA prior to the over-mentioned check.

	if (!(alloc_flags & ALLOC_CMA))
		free_pages -= zone_page_state(z, NR_FREE_CMA_PAGES);

This prevents the zone from being drained from pages available for
non-movable allocations.

The second check prevents the zone from getting too fragmented.

	for (o = 0; o < order; o++) {
		free_pages -= z->free_area[o].nr_free << o;
		min >>= 1;
		if (free_pages <= min)
			return false;
	}

The field z->free_area[o].nr_free is equal to the number of free pages
including free CMA pages.  Therefore the CMA pages are subtracted twice.
This may cause a false positive fail of __zone_watermark_ok() if the CMA
area gets strongly fragmented.  In such a case there are many 0-order
free pages located in CMA.  Those pages are subtracted twice therefore
they will quickly drain free_pages during the check against
fragmentation.  The test fails even though there are many free non-cma
pages in the zone.

This patch fixes this issue by subtracting CMA pages only for a purpose of
(free_pages <= min + lowmem_reserve) check.

Laura said:

  We were observing allocation failures of higher order pages (order 5 =
  128K typically) under tight memory conditions resulting in driver
  failure.  The output from the page allocation failure showed plenty of
  free pages of the appropriate order/type/zone and mostly CMA pages in
  the lower orders.

  For full disclosure, we still observed some page allocation failures
  even after applying the patch but the number was drastically reduced and
  those failures were attributed to fragmentation/other system issues.

Change-Id: Ic2c0c233993c41c630e24d71df5e12aa614588e5
CRs-Fixed:549847
Signed-off-by: Tomasz Stanislawski <t.stanislaws@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Tested-by: Laura Abbott <lauraa@codeaurora.org>
Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Cc: Mel Gorman <mel@csn.ul.ie>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: <stable@vger.kernel.org>	[3.7+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Git-commit: 026b08147923142e925a7d0aaa39038055ae0156
Git-repo: https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git
Signed-off-by: Srinivasarao P <spathi@codeaurora.org>
mmc: core: remove the polling for BKOPS completion

The original intention of polling for BKOPS completion was to give
the card enough time to perform the BKOPS before it is runtime suspended.
But as the BKOPS completion polling was happening in a different
context, it may race with card runtime/platform suspend which is quite
difficult to fix. So instead of BKOPS polling, let the runtime suspend
get deferred if the BKOPS is running on the card. Also if BKOPS is running
when platform suspend is triggered, stop the BKOPS before suspending the
card.

Conflicts:
	drivers/mmc/core/core.c
	include/linux/mmc/card.h

CRs-Fixed: 489523
Change-Id: I21e524dc2da37c4985c210abfaca00a28049c651
Signed-off-by: Maya Erez <merez@codeaurora.org>
Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org>
mmc: core: Fix MMC clock scaling in case of tuning failure

When the clock scaling state is changed from MMC_LOAD_LOW to
MMC_LOAD_HIGH, the clocks are first scaled up and then tuning
is performed. But in case of tuning failure, the current code
does nothing but still retain the previous clock scale stats
(state and curr_freq within struct clk_scaling). Hence, correct
it to scale down the clocks in case of tuning failure so that
clock scaling stats reflect the correct status. This also helps
proceed with data transfers at lower clock rate in such cases.

Change-Id: I7e9379d1e3ddc863132af31019604c22a42f8d59
Signed-off-by: Sahitya Tummala <stummala@codeaurora.org>
mmc: core: expose HPI capability to SWITCH commands

Some of the time consuming operations such as BKOPS, SANITIZE, CACHE
flush/off use the SWITCH command (CMD6) but as these operations don't
have card specification defined timeout for completion, we may see
timeout errors if card doesn't complete the operation within the SW
defined timeout. If SW defined timeout is hit, above operations are
considered to be failed and no real recovery mechanism is implemented
after timeout.

Most of the above operations (BKOPS/SANITIZE/CACHE flush/off) can be
interrupted by sending the HPI (High Priority Interrupt) command to card
if they taking longer than expected. This change adds the base support
which will these operations to be HPIed after timeout.

Change-Id: Ibd9061525756aaae656b1ceeeaed62e04fb80cce
Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org>
mmc: core: handle flush requests timeout

According to the eMMC 4.5 spec "Flushing a large amount of cached data may
take very unpredictably long time". Therefore the timeout for FLUSH should
be increased to prevent timeouts.

In case the timeout occurs HPI issued.

CRs-Fixed: 500874
Change-Id: Ib00d087d3fe2fa72f5eac096976d3f24b5e4966a
Signed-off-by: Maya Erez <merez@codeaurora.org>
Signed-off-by: Konstantin Dorfman <kdorfman@codeaurora.org>