dm: push md->immutable_target optimization down to __process_bio()

Also, update associated stale comment in __bind().

Signed-off-by: Mike Snitzer <snitzer@redhat.com>

dm: change max_io_len() to use blk_max_size_offset()

Using blk_max_size_offset() enables DM core's splitting to impose
ti->max_io_len (via q->limits.chunk_sectors) and also fallback to
respecting q->limits.max_sectors if chunk_sectors isn't set.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>

dm table: stack 'chunk_sectors' limit to account for target-specific splitting

If target set ti->max_io_len it must be used when stacking
DM device's queue_limits to establish a 'chunk_sectors' that is
compatible with the IO stack.

By using lcm_not_zero() care is taken to avoid blindly overriding the
chunk_sectors limit stacked up by blk_stack_limits().

Depends-on: 07d098e6bbad ("block: allow 'chunk_sectors' to be non-power-of-2")
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

Merge remote-tracking branch 'jens/for-5.10/block' into dm-5.10

DM depends on these block 5.10 commits:

22ada802ede8 block: use lcm_not_zero() when stacking chunk_sectors
07d098e6bbad block: allow 'chunk_sectors' to be non-power-of-2
021a24460dc2 block: add QUEUE_FLAG_NOWAIT
6abc49468eea dm: add support for REQ_NOWAIT and enable it for linear target

Signed-off-by: Mike Snitzer <snitzer@redhat.com>

block-mq: fix comments in blk_mq_queue_tag_busy_iter

'f5bbbbe4d635 ("blk-mq: sync the update nr_hw_queues with
blk_mq_queue_tag_busy_iter")' introduce a bug what we may sleep between
rcu lock. Then '530ca2c9bd69 ("blk-mq: Allow blocking queue tag iter
callbacks")' fix it by get request_queue's ref. And 'a9a808084d6a ("block:
Remove the synchronize_rcu() call from __blk_mq_update_nr_hw_queues()")'
remove the synchronize_rcu in __blk_mq_update_nr_hw_queues. We need
update the confused comments in blk_mq_queue_tag_busy_iter.

Signed-off-by: yangerkun <yangerkun@huawei.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

blk-mq: add cond_resched() in __blk_mq_alloc_rq_maps()

We found blk_mq_alloc_rq_maps() takes more time in kernel space when
testing nvme device hot-plugging. The test and anlysis as below.

Debug code,
1, blk_mq_alloc_rq_maps():
        u64 start, end;
        depth = set->queue_depth;
        start = ktime_get_ns();
        pr_err("[%d:%s switch:%ld,%ld] queue depth %d, nr_hw_queues %d\n",
                        current->pid, current->comm, current->nvcsw, current->nivcsw,
                        set->queue_depth, set->nr_hw_queues);
        do {
                err = __blk_mq_alloc_rq_maps(set);
                if (!err)
                        break;

                set->queue_depth >>= 1;
                if (set->queue_depth < set->reserved_tags + BLK_MQ_TAG_MIN) {
                        err = -ENOMEM;
                        break;
                }
        } while (set->queue_depth);
        end = ktime_get_ns();
        pr_err("[%d:%s switch:%ld,%ld] all hw queues init cost time %lld ns\n",
                        current->pid, current->comm,
                        current->nvcsw, current->nivcsw, end - start);

2, __blk_mq_alloc_rq_maps():
        u64 start, end;
        for (i = 0; i < set->nr_hw_queues; i++) {
                start = ktime_get_ns();
                if (!__blk_mq_alloc_rq_map(set, i))
                        goto out_unwind;
                end = ktime_get_ns();
                pr_err("hw queue %d init cost time %lld ns\n", i, end - start);
        }

Test nvme hot-plugging with above debug code, we found it totally cost more
than 3ms in kernel space without being scheduled out when alloc rqs for all
16 hw queues with depth 1023, each hw queue cost about 140-250us. The cost
time will be increased with hw queue number and queue depth increasing. And
in an extreme case, if __blk_mq_alloc_rq_maps() returns -ENOMEM, it will try
"queue_depth >>= 1", more time will be consumed.
[  428.428771] nvme nvme0: pci function 10000:01:00.0
[  428.428798] nvme 10000:01:00.0: enabling device (0000 -> 0002)
[  428.428806] pcieport 10000:00:00.0: can't derive routing for PCI INT A
[  428.428809] nvme 10000:01:00.0: PCI INT A: no GSI
[  432.593374] [4688:kworker/u33:8 switch:663,2] queue depth 30, nr_hw_queues 1
[  432.593404] hw queue 0 init cost time 22883 ns
[  432.593408] [4688:kworker/u33:8 switch:663,2] all hw queues init cost time 35960 ns
[  432.595953] nvme nvme0: 16/0/0 default/read/poll queues
[  432.595958] [4688:kworker/u33:8 switch:700,2] queue depth 1023, nr_hw_queues 16
[  432.596203] hw queue 0 init cost time 242630 ns
[  432.596441] hw queue 1 init cost time 235913 ns
[  432.596659] hw queue 2 init cost time 216461 ns
[  432.596877] hw queue 3 init cost time 215851 ns
[  432.597107] hw queue 4 init cost time 228406 ns
[  432.597336] hw queue 5 init cost time 227298 ns
[  432.597564] hw queue 6 init cost time 224633 ns
[  432.597785] hw queue 7 init cost time 219954 ns
[  432.597937] hw queue 8 init cost time 150930 ns
[  432.598082] hw queue 9 init cost time 143496 ns
[  432.598231] hw queue 10 init cost time 147261 ns
[  432.598397] hw queue 11 init cost time 164522 ns
[  432.598542] hw queue 12 init cost time 143401 ns
[  432.598692] hw queue 13 init cost time 148934 ns
[  432.598841] hw queue 14 init cost time 147194 ns
[  432.598991] hw queue 15 init cost time 148942 ns
[  432.598993] [4688:kworker/u33:8 switch:700,2] all hw queues init cost time 3035099 ns
[  432.602611]  nvme0n1: p1

So use this patch to trigger schedule between each hw queue init, to avoid
other threads getting stuck. It is not in atomic context when executing
__blk_mq_alloc_rq_maps(), so it is safe to call cond_resched().

Signed-off-by: Xianting Tian <tian.xianting@h3c.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

iocost: consider iocgs with active delays for debt forgiveness

An iocg may have 0 debt but non-zero delay. The current debt forgiveness
logic doesn't act on such iocgs. This can lead to unexpected behaviors - an
iocg with a little bit of debt will have its delay canceled through debt
forgiveness but one w/o any debt but active delay will have to wait out
until its delay decays out.

This patch updates the debt handling logic so that it treats delays the same
as debts. If either debt or delay is active, debt forgiveness logic kicks in
and acts on both the same way.

Also, avoid turning the debt and delay directly to zero as that can confuse
state transitions.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

iocost: add iocg_forgive_debt tracepoint

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

iocost: reimplement debt forgiveness using average usage

Debt forgiveness logic was counting the number of consecutive !busy periods
as the trigger condition. While this usually works, it can easily be thrown
off by temporary fluctuations especially on configurations w/ short periods.

This patch reimplements debt forgiveness so that:

* Use the average usage over the forgiveness period instead of counting
  consecutive periods.

* Debt is reduced at around the target rate (1/2 every 100ms) regardless of
  ioc period duration.

* Usage threshold is raised to 50%. Combined with the preceding changes and
  the switch to average usage, this makes debt forgivness a lot more
  effective at reducing the amount of unnecessary idleness.

* Constants are renamed with DFGV_ prefix.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

iocost: recalculate delay after debt reduction

Debt sets the initial delay duration which is decayed over time. The current
debt reduction halved the debt but didn't change the delay. It prevented
future debts from increasing delay but didn't do anything to lower the
existing delay, limiting the mechanism's ability to reduce unnecessary
idling.

Reset iocg->delay to 0 after debt reduction so that iocg_kick_waitq()
recalculates new delay value based on the reduced debt amount.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

iocost: replace nr_shortages cond in ioc_forgive_debts() with busy_level one

Debt reduction was blocked if any iocg was short on budget in the past
period to avoid reducing debts while some iocgs are saturated. However, this
ends up unnecessarily blocking debt reduction due to temporary local
imbalances when the device is generally being underutilized, while also
failing to block when the underlying device is overwhelmed and the usage
becomes low from high latency.

Given that debt accumulation mostly happens with swapout bursts which can
significantly deteriorate the underlying device's latency response, the
current logic is not great.

Let's replace it with ioc->busy_level based condition so that we block debt
reduction when the underlying device is being saturated. ioc_forgive_debts()
call is moved after busy_level determination.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

iocost: factor out ioc_forgive_debts()

Debt reduction logic is going to be improved and expanded. Factor it out
into ioc_forgive_debts() and generalize the comment a bit. No functional
change.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

dm: add support for REQ_NOWAIT and enable it for linear target

Add DM target feature flag DM_TARGET_NOWAIT which advertises that
target works with REQ_NOWAIT bios.

Add dm_table_supports_nowait() and update dm_table_set_restrictions()
to set/clear QUEUE_FLAG_NOWAIT accordingly.

Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: add QUEUE_FLAG_NOWAIT

Add QUEUE_FLAG_NOWAIT to allow a block device to advertise support for
REQ_NOWAIT. Bio-based devices may set QUEUE_FLAG_NOWAIT where
applicable.

Update QUEUE_FLAG_MQ_DEFAULT to include QUEUE_FLAG_NOWAIT.  Also
update submit_bio_checks() to verify it is set for REQ_NOWAIT bios.

Reported-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Suggested-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

vsprintf: use bd_partno in bdev_name

No need to go through the hd_struct to find the partition number.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: use bd_partno in bdevname

No need to go through the hd_struct to find the partition number.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

target/iblock: fix holder printing in iblock_show_configfs_dev_params

bd_contains is never NULL for an open block device.  In addition ibd_bd
is always set to a block device that was exclusively opened by the
target code, so the holder is guranteed to be ib_dev as well.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

drbd: don't set ->bd_contains

The ->bd_contains field is set by __blkdev_get and drivers have no
business manipulating it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

drbd: don't detour through bd_contains for the gendisk

bd_disk is set on all block devices, including those for partitions.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

md: don't detour through bd_contains for the gendisk

bd_disk is set on all block devices, including those for partitions.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Song Liu <song@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

md: compare bd_disk instead of bd_contains

To check for partitions of the same disk bd_contains works as well, but
bd_disk is way more obvious.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Song Liu <song@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: add a bdev_is_partition helper

Add a littler helper to make the somewhat arcane bd_contains checks a
little more obvious.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Documentation/hdio: fix up obscure bd_contains references

bd_contains is an implementation detail and should not be mentioned in
a userspace API documentation.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

bdi: replace BDI_CAP_NO_{WRITEBACK,ACCT_DIRTY} with a single flag

Replace the two negative flags that are always used together with a
single positive flag that indicates the writeback capability instead
of two related non-capabilities.  Also remove the pointless wrappers
to just check the flag.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

bdi: invert BDI_CAP_NO_ACCT_WB

Replace BDI_CAP_NO_ACCT_WB with a positive BDI_CAP_WRITEBACK_ACCT to
make the checks more obvious.  Also remove the pointless
bdi_cap_account_writeback wrapper that just obsfucates the check.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

bdi: replace BDI_CAP_STABLE_WRITES with a queue and a sb flag

The BDI_CAP_STABLE_WRITES is one of the few bits of information in the
backing_dev_info shared between the block drivers and the writeback code.
To help untangling the dependency replace it with a queue flag and a
superblock flag derived from it.  This also helps with the case of e.g.
a file system requiring stable writes due to its own checksumming, but
not forcing it on other users of the block device like the swap code.

One downside is that we an't support the stable_pages_required bdi
attribute in sysfs anymore.  It is replaced with a queue attribute which
also is writable for easier testing.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

mm: use SWP_SYNCHRONOUS_IO more intelligently

There is no point in trying to call bdev_read_page if SWP_SYNCHRONOUS_IO
is not set, as the device won't support it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

bdi: remove BDI_CAP_SYNCHRONOUS_IO

BDI_CAP_SYNCHRONOUS_IO is only checked in the swap code, and used to
decided if ->rw_page can be used on a block device.  Just check up for
the method instead.  The only complication is that zram needs a second
set of block_device_operations as it can switch between modes that
actually support ->rw_page and those who don't.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

bdi: remove BDI_CAP_CGROUP_WRITEBACK

Just checking SB_I_CGROUPWB for cgroup writeback support is enough.
Either the file system allocates its own bdi (e.g. btrfs), in which case
it is known to support cgroup writeback, or the bdi comes from the block
layer, which always supports cgroup writeback.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: lift setting the readahead size into the block layer

Drivers shouldn't really mess with the readahead size, as that is a VM
concept.  Instead set it based on the optimal I/O size by lifting the
algorithm from the md driver when registering the disk.  Also set
bdi->io_pages there as well by applying the same scheme based on
max_sectors.  To ensure the limits work well for stacking drivers a
new helper is added to update the readahead limits from the block
limits, which is also called from disk_stack_limits.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Acked-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

md: update the optimal I/O size on reshape

The raid5 and raid10 drivers currently update the read-ahead size,
but not the optimal I/O size on reshape.  To prepare for deriving the
read-ahead size from the optimal I/O size make sure it is updated
as well.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Acked-by: Song Liu <song@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

bdi: initialize ->ra_pages and ->io_pages in bdi_init

Set up a readahead size by default, as very few users have a good
reason to change it.  This means code, ecryptfs, and orangefs now
set up the values while they were previously missing it, while ubifs,
mtd and vboxsf manually set it to 0 to avoid readahead.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Acked-by: David Sterba <dsterba@suse.com> [btrfs]
Acked-by: Richard Weinberger <richard@nod.at> [ubifs, mtd]
Signed-off-by: Jens Axboe <axboe@kernel.dk>

aoe: set an optimal I/O size

aoe forces a larger readahead size, but any reason to do larger I/O
is not limited to readahead.  Also set the optimal I/O size, and
remove the local constants in favor of just using SZ_2G.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

bcache: inherit the optimal I/O size

Inherit the optimal I/O size setting just like the readahead window,
as any reason to do larger I/O does not apply to just readahead.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Acked-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

drbd: remove dead code in device_to_statistics

Ever since the switch to blk-mq, a lower device not used for VM
writeback will not be marked congested, so the check will never
trigger.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

fs: remove the unused SB_I_MULTIROOT flag

The last user of SB_I_MULTIROOT is disappeared with commit f2aedb713c28
("NFS: Add fs_context support.")

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: mark blkdev_get static

There are no users outside the core block code left now.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

PM: mm: cleanup swsusp_swap_check

Use blkdev_get_by_dev instead of bdget + blkdev_get.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

mm: split swap_type_of

swap_type_of is used for two entirely different purposes:

 (1) check what swap type a given device/offset corresponds to
 (2) find the first available swap device that can be written to

Mixing both in a single function creates an unreadable mess.  Create two
separate functions instead, and switch both to pass a dev_t instead of
a struct block_device to further simplify the code.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

PM: rewrite is_hibernate_resume_dev to not require an inode

Just check the dev_t to help simplifying the code.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

mm: cleanup claim_swapfile

Use blkdev_get_by_dev instead of bdgrab + blkdev_get.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

ocfs2: cleanup o2hb_region_dev_store

Use blkdev_get_by_dev instead of igrab (aka open coded bdgrab) +
blkdev_get.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

dasd: cleanup dasd_scan_partitions

Use blkdev_get_by_dev instead of bdget_disk + blkdev_get.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Stefan Haberland <sth@linux.ibm.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

raw: don't keep unopened block device around

Turn binding into a normal dev_t as the struct block device doesn't
buy us anything and use blkdev_open_by_dev to actually open it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

zram: cleanup backing_dev_store

Use blkdev_get_by_dev instead of bdgrab + blkdev_get.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

pktcdvd: use blkdev_get_by_dev instead of open coding it

Replace bdget + blkdev_get by blkdev_get_by_dev.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

pktcdvd: remove the if 0'ed pkt_start_recovery function

Remove code which has been dead since the initial commit.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: cleanup blkdev_bszset

Use blkdev_get_by_dev instead of bdgrab + blkdev_get.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: cleanup partition scanning in register_disk

Use blkdev_get_by_dev instead of open coding it using bdget_disk +
blkdev_get, and split the code to read the partition table into a
separate helper to make it a little more obvious.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: move the NEED_PART_SCAN flag to struct gendisk

We can only scan for partitions on the whole disk, so move the flag
from struct block_device to struct gendisk.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: allow 'chunk_sectors' to be non-power-of-2

It is possible, albeit more unlikely, for a block device to have a non
power-of-2 for chunk_sectors (e.g. 10+2 RAID6 with 128K chunk_sectors,
which results in a full-stripe size of 1280K. This causes the RAID6's
io_opt to be advertised as 1280K, and a stacked device _could_ then be
made to use a blocksize, aka chunk_sectors, that matches non power-of-2
io_opt of underlying RAID6 -- resulting in stacked device's
chunk_sectors being a non power-of-2).

Update blk_queue_chunk_sectors() and blk_max_size_offset() to
accommodate drivers that need a non power-of-2 chunk_sectors.

Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: use lcm_not_zero() when stacking chunk_sectors

Like 'io_opt', blk_stack_limits() should stack 'chunk_sectors' using
lcm_not_zero() rather than min_not_zero() -- otherwise the final
'chunk_sectors' could result in sub-optimal alignment of IO to
component devices in the IO stack.

Also, if 'chunk_sectors' isn't a multiple of 'physical_block_size'
then it is a bug in the driver and the device should be flagged as
'misaligned'.

Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: fix bmd->is_null_mapped initialization

bmd is allocated using kmalloc in bio_alloc_map_data, so make sure
is_null_mapped is properly initialized to false for the !null_mapped
case.

Fixes: f3256075ba49 ("block: remove the BIO_NULL_MAPPED flag")
Reported-by: Marc Hartmayer <mhartmay@linux.ibm.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: drop double zeroing

sg_init_table zeroes its first argument, so the allocation of that argument
doesn't have to.

the semantic patch that makes this change is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@@
expression x;
@@

x =
- kzalloc
+ kmalloc
 (...)
...
sg_init_table(x,...)
// </smpl>

Signed-off-by: Julia Lawall <Julia.Lawall@inria.fr>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

dm crypt: document encrypted keyring key option

Commit 27f5411a718c4 ("dm crypt: support using encrypted keys")
introduced support for encrypted keyring type.

Fix documentation in admin guide to mention this type.

Fixes: 27f5411a718c4 ("dm crypt: support using encrypted keys")
Signed-off-by: Milan Broz <gmazyland@gmail.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

dm crypt: document new no_workqueue flags

Commit 39d42fa96ba1 ("dm crypt: add flags to optionally bypass kcryptd
workqueues") introduced new dm-crypt 'no_read_workqueue' and
'no_write_workqueue' flags.

Add documentation to admin guide for them.

Fixes: 39d42fa96ba1 ("dm crypt: add flags to optionally bypass kcryptd workqueues")
Signed-off-by: Milan Broz <gmazyland@gmail.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

dm: fix comment in dm_process_bio()

Refer to the correct function (->submit_bio instead of ->queue_bio).
Also, add details about why using blk_queue_split() isn't needed for
dm_wq_work()'s call to dm_process_bio().

Fixes: c62b37d96b6eb ("block: move ->make_request_fn to struct block_device_operations")
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

dm: fix bio splitting and its bio completion order for regular IO

dm_queue_split() is removed because __split_and_process_bio() _must_
handle splitting bios to ensure proper bio submission and completion
ordering as a bio is split.

Otherwise, multiple recursive calls to ->submit_bio will cause multiple
split bios to be allocated from the same ->bio_split mempool at the same
time. This would result in deadlock in low memory conditions because no
progress could be made (only one bio is available in ->bio_split
mempool).

This fix has been verified to still fix the loss of performance, due
to excess splitting, that commit 120c9257f5f1 provided.

Fixes: 120c9257f5f1 ("Revert "dm: always call blk_queue_split() in dm_process_bio()"")
Cc: stable@vger.kernel.org # 5.0+, requires custom backport due to 5.9 changes
Reported-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

Merge tag 'for-linus' of git://git./virt/kvm/kvm

Pull kvm fixes from Paolo Bonzini:
 "ARM:
   - fix fault on page table writes during instruction fetch

  s390:
   - doc improvement

  x86:
   - The obvious patches are always the ones that turn out to be
     completely broken. /me hangs his head in shame"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  Revert "KVM: Check the allocation of pv cpu mask"
  KVM: arm64: Remove S1PTW check from kvm_vcpu_dabt_iswrite()
  KVM: arm64: Assume write fault on S1PTW permission fault on instruction fetch
  docs: kvm: add documentation for KVM_CAP_S390_DIAG318

Merge tag 'libnvdimm-fixes-5.9-rc7' of git://git./linux/kernel/git/nvdimm/nvdimm

Pull libnvdimm fix from Dan Williams:
 "Fix compilation for the new dax_supported() exported helper"

* tag 'libnvdimm-fixes-5.9-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm:
  dax: Fix compilation for CONFIG_DAX && !CONFIG_FS_DAX

dax: Fix compilation for CONFIG_DAX && !CONFIG_FS_DAX

dax_supported() is defined whenever CONFIG_DAX is enabled. So dummy
implementation should be defined only in !CONFIG_DAX case, not in
!CONFIG_FS_DAX case.

Fixes: e2ec51282545 ("dm: Call proper helper to determine dax support")
Cc: <stable@vger.kernel.org>
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

Linux 5.9-rc6

Merge tag 'core_urgent_for_v5.9_rc6' of git://git./linux/kernel/git/tip/tip

Pull syscall tracing fix from Borislav Petkov:
 "Fix the seccomp syscall rewriting so that trace and audit see the
  rewritten syscall number, from Kees Cook"

* tag 'core_urgent_for_v5.9_rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  core/entry: Report syscall correctly for trace and audit

Merge tag 'objtool_urgent_for_v5.9_rc6' of git://git./linux/kernel/git/tip/tip

Pull objtool fix from Borislav Petkov:
 "Fix noreturn detection for ignored sibling functions (Josh Poimboeuf)"

* tag 'objtool_urgent_for_v5.9_rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  objtool: Fix noreturn detection for ignored functions

Merge tag 'locking_urgent_for_v5.9_rc6' of git://git./linux/kernel/git/tip/tip

Pull locking fixes from Borislav Petkov:
 "Two fixes from the locking/urgent pile:

   - Fix lockdep's detection of "USED" <- "IN-NMI" inversions (Peter
     Zijlstra)

   - Make percpu-rwsem operations on the semaphore's ->read_count
     IRQ-safe because it can be used in an IRQ context (Hou Tao)"

* tag 'locking_urgent_for_v5.9_rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  locking/percpu-rwsem: Use this_cpu_{inc,dec}() for read_count
  locking/lockdep: Fix "USED" <- "IN-NMI" inversions

Merge tag 'efi-urgent-for-v5.9-rc5' of git://git./linux/kernel/git/tip/tip

Pull EFI fix from Borislav Petkov:
 "Ensure that the EFI bootloader control module only probes successfully
  on systems that support the EFI SetVariable runtime service"

[ Tag and commit from Ard Biesheuvel, forwarded by Borislav ]

* tag 'efi-urgent-for-v5.9-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  efi: efibc: check for efivars write capability

Merge tag 'x86_urgent_for_v5.9_rc6' of git://git./linux/kernel/git/tip/tip

Pull x86 fixes from Borislav Petkov:

 - A defconfig fix (Daniel Díaz)

 - Disable relocation relaxation for the compressed kernel when not
   built as -pie as in that case kernels built with clang and linked
   with LLD fail to boot due to the linker optimizing some instructions
   in non-PIE form; the gory details in the commit message (Arvind
   Sankar)

 - A fix for the "bad bp value" warning issued by the frame-pointer
   unwinder (Josh Poimboeuf)

* tag 'x86_urgent_for_v5.9_rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/unwind/fp: Fix FP unwinding in ret_from_fork
  x86/boot/compressed: Disable relocation relaxation
  x86/defconfigs: Explicitly unset CONFIG_64BIT in i386_defconfig

Merge tag 'libnvdimm-fixes-5.9-rc6' of git://git./linux/kernel/git/nvdimm/nvdimm

Pull libnvdimm fixes from Dan Williams:
 "A handful of fixes to address a string of mistakes in the mechanism
  for device-mapper to determine if its component devices are dax
  capable.

   - Fix an original bug in device-mapper table reference counting when
     interrogating dax capability in the component device. This bug was
     hidden by the following bug.

   - Fix device-mapper to use the proper helper (dax_supported() instead
     of the leaf helper generic_fsdax_supported()) to determine dax
     operation of a stacked block device configuration. The original
     implementation is only valid for one level of dax-capable block
     device stacking. This bug was discovered while fixing the below
     regression.

   - Fix an infinite recursion regression introduced by broken attempts
     to quiet the generic_fsdax_supported() path and make it bail out
     before logging "dax capability not found" errors"

* tag 'libnvdimm-fixes-5.9-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm:
  dax: Fix stack overflow when mounting fsdax pmem device
  dm: Call proper helper to determine dax support
  dm/dax: Fix table reference counts

Merge tag 'kvm-s390-master-5.9-1' of git://git./linux/kernel/git/kvms390/linux into kvm-master

KVM: s390: add documentation for KVM_CAP_S390_DIAG318

diag318 code was merged in 5.9-rc1, let us add some
missing documentation

Merge tag 'kvmarm-fixes-5.9-2' of git://git./linux/kernel/git/kvmarm/kvmarm into kvm-master

KVM/arm64 fixes for 5.9, take #2

- Fix handling of S1 Page Table Walk permission fault at S2
  on instruction fetch
- Cleanup kvm_vcpu_dabt_iswrite()

Revert "KVM: Check the allocation of pv cpu mask"

The commit 0f990222108d ("KVM: Check the allocation of pv cpu mask") we
have in 5.9-rc5 has two issue:
1) Compilation fails for !CONFIG_SMP, see:
   https://bugzilla.kernel.org/show_bug.cgi?id=209285

2) This commit completely disables PV TLB flush, see
   https://lore.kernel.org/kvm/87y2lrnnyf.fsf@vitty.brq.redhat.com/

The allocation problem is likely a theoretical one, if we don't
have memory that early in boot process we're likely doomed anyway.
Let's solve it properly later.

This reverts commit 0f990222108d214a0924d920e6095b58107d7b59.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Merge tag 'riscv-for-linus-5.9-rc6' of git://git./linux/kernel/git/riscv/linux

Pull RISC-V fixes from Palmer Dabbelt:

 - A fix for a lockdep issue to avoid an asserting triggering during
   early boot. There shouldn't be any incorrect behavior as the system
   isn't concurrent at the time.

 - The addition of a missing fence when installing early fixmap
   mappings.

 - A corretion to the K210 device tree's interrupt map.

 - A fix for M-mode timer handling on the K210.

* tag 'riscv-for-linus-5.9-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux:
  RISC-V: Resurrect the MMIO timer implementation for M-mode systems
  riscv: Fix Kendryte K210 device tree
  riscv: Add sfence.vma after early page table changes
  RISC-V: Take text_mutex in ftrace_init_nop()

Merge tag 'usb-5.9-rc6' of git://git./linux/kernel/git/gregkh/usb

Pull USB/Thunderbolt fixes from Greg KH:
 "Here are some small USB and one Thunderbolt driver fixes.

  Nothing major at all, just some fixes for reported issues, and a quirk
  addition:

   - typec fixes

   - UAS disconnect fix

   - usblp race fix

   - ehci-hcd modversions build fix

   - ignore wakeup quirk table addition

   - thunderbolt DROM read fix

  All of these have been in linux-next with no reported issues"

* tag 'usb-5.9-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb:
  usblp: fix race between disconnect() and read()
  ehci-hcd: Move include to keep CRC stable
  usb: typec: intel_pmc_mux: Handle SCU IPC error conditions
  USB: quirks: Add USB_QUIRK_IGNORE_REMOTE_WAKEUP quirk for BYD zhaoxin notebook
  USB: UAS: fix disconnect by unplugging a hub
  usb: typec: ucsi: Prevent mode overrun
  usb: typec: ucsi: acpi: Increase command completion timeout value
  thunderbolt: Retry DROM read once if parsing fails

Merge tag 'tty-5.9-rc6' of git://git./linux/kernel/git/gregkh/tty

Pull tty/serial/fbcon fixes from Greg KH:
 "Here are some small tty/serial and one more fbcon fix.

  They include:

   - serial core locking regression fixes

   - new device ids for 8250_pci driver

   - fbcon fix for syzbot found issue

  All have been in linux-next with no reported issues"

* tag 'tty-5.9-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty:
  fbcon: Fix user font detection test at fbcon_resize().
  serial: 8250_pci: Add Realtek 816a and 816b
  serial: core: fix console port-lock regression
  serial: core: fix port-lock initialisation

Merge tag 'edac_urgent_for_v5.9_rc6' of git://git./linux/kernel/git/ras/ras

Pull EDAC fixes from Borislav Petkov:
 "Two fixes for resulting from CONFIG_DEBUG_TEST_DRIVER_REMOVE=y
  experiments:

   - complete a previous fix to reset a local structure containing
     scanned system data properly so that the driver rescans, as it
     should, on a second load.

   - address a refcount underflow due to not paying attention to the
     driver whitelest on unregister"

* tag 'edac_urgent_for_v5.9_rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/ras/ras:
  EDAC/ghes: Check whether the driver is on the safe list correctly
  EDAC/ghes: Clear scanned data on unload

Merge branch 'for-linus' of git://git./linux/kernel/git/dtor/input

Pull input fixes from Dmitry Torokhov:
 "Just a couple of driver quirks"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input:
  Input: trackpoint - add new trackpoint variant IDs
  Input: i8042 - add Entroware Proteus EL07R4 to nomux and reset lists

mm: fix wake_page_function() comment typos

Sedat Dilek pointed out some silly comment typo issues.

Reported-by: Sedat Dilek <sedat.dilek@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Merge tag 'kbuild-fixes-v5.9-3' of git://git./linux/kernel/git/masahiroy/linux-kbuild

Pull Kbuild fixes from Masahiro Yamada:
 "Fix qconf warnings and revive help message"

* tag 'kbuild-fixes-v5.9-3' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
  kconfig: qconf: revive help message in the info view
  kconfig: qconf: fix incomplete type 'struct gstr' warning
  kconfig: qconf: use delete[] instead of delete to free array (again)

dax: Fix stack overflow when mounting fsdax pmem device

When mounting fsdax pmem device, commit 6180bb446ab6 ("dax: fix
detection of dax support for non-persistent memory block devices")
introduces the stack overflow [1][2]. Here is the call path for
mounting ext4 file system:
  ext4_fill_super
    bdev_dax_supported
      __bdev_dax_supported
        dax_supported
          generic_fsdax_supported
            __generic_fsdax_supported
              bdev_dax_supported

The call path leads to the infinite calling loop, so we cannot
call bdev_dax_supported() in __generic_fsdax_supported(). The sanity
checking of the variable 'dax_dev' is moved prior to the two
bdev_dax_pgoff() checks [3][4].

[1] https://lore.kernel.org/linux-nvdimm/1420999447.1004543.1600055488770.JavaMail.zimbra@redhat.com/
[2] https://lore.kernel.org/linux-nvdimm/alpine.LRH.2.02.2009141131220.30651@file01.intranet.prod.int.rdu2.redhat.com/
[3] https://lore.kernel.org/linux-nvdimm/CA+RJvhxBHriCuJhm-D8NvJRe3h2MLM+ZMFgjeJjrRPerMRLvdg@mail.gmail.com/
[4] https://lore.kernel.org/linux-nvdimm/20200903160608.GU878166@iweiny-DESK2.sc.intel.com/

Fixes: 6180bb446ab6 ("dax: fix detection of dax support for non-persistent memory block devices")
Reported-by: Yi Zhang <yi.zhang@redhat.com>
Reported-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Adrian Huang <ahuang12@lenovo.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Tested-by: Ritesh Harjani <riteshh@linux.ibm.com>
Cc: Coly Li <colyli@suse.de>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: John Pittman <jpittman@redhat.com>
Link: https://lore.kernel.org/r/20200917111549.6367-1-adrianhuang0701@gmail.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

dm: Call proper helper to determine dax support

DM was calling generic_fsdax_supported() to determine whether a device
referenced in the DM table supports DAX. However this is a helper for "leaf" device drivers so that
they don't have to duplicate common generic checks. High level code
should call dax_supported() helper which that calls into appropriate
helper for the particular device. This problem manifested itself as
kernel messages:

dm-3: error: dax access failed (-95)

when lvm2-testsuite run in cases where a DM device was stacked on top of
another DM device.

Fixes: 7bf7eac8d648 ("dax: Arrange for dax_supported check to span multiple devices")
Cc: <stable@vger.kernel.org>
Tested-by: Adrian Huang <ahuang12@lenovo.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Acked-by: Mike Snitzer <snitzer@redhat.com>
Reported-by: kernel test robot <lkp@intel.com>
Link: https://lore.kernel.org/r/160061715195.13131.5503173247632041975.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

dm/dax: Fix table reference counts

A recent fix to the dm_dax_supported() flow uncovered a latent bug. When
dm_get_live_table() fails it is still required to drop the
srcu_read_lock(). Without this change the lvm2 test-suite triggers this
warning:

    # lvm2-testsuite --only pvmove-abort-all.sh

    WARNING: lock held when returning to user space!
    5.9.0-rc5+ #251 Tainted: G           OE
    ------------------------------------------------
    lvm/1318 is leaving the kernel with locks still held!
    1 lock held by lvm/1318:
     #0: ffff9372abb5a340 (&md->io_barrier){....}-{0:0}, at: dm_get_live_table+0x5/0xb0 [dm_mod]

...and later on this hang signature:

    INFO: task lvm:1344 blocked for more than 122 seconds.
          Tainted: G           OE     5.9.0-rc5+ #251
    "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
    task:lvm             state:D stack:    0 pid: 1344 ppid:     1 flags:0x00004000
    Call Trace:
     __schedule+0x45f/0xa80
     ? finish_task_switch+0x249/0x2c0
     ? wait_for_completion+0x86/0x110
     schedule+0x5f/0xd0
     schedule_timeout+0x212/0x2a0
     ? __schedule+0x467/0xa80
     ? wait_for_completion+0x86/0x110
     wait_for_completion+0xb0/0x110
     __synchronize_srcu+0xd1/0x160
     ? __bpf_trace_rcu_utilization+0x10/0x10
     __dm_suspend+0x6d/0x210 [dm_mod]
     dm_suspend+0xf6/0x140 [dm_mod]

Fixes: 7bf7eac8d648 ("dax: Arrange for dax_supported check to span multiple devices")
Cc: <stable@vger.kernel.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Alasdair Kergon <agk@redhat.com>
Cc: Mike Snitzer <snitzer@redhat.com>
Reported-by: Adrian Huang <ahuang12@lenovo.com>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Tested-by: Adrian Huang <ahuang12@lenovo.com>
Link: https://lore.kernel.org/r/160045867590.25663.7548541079217827340.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

kconfig: qconf: revive help message in the info view

Since commit 68fd110b3e7e ("kconfig: qconf: remove redundant help in
the info view"), the help message is no longer displayed.

I intended to drop duplicated "Symbol:", "Type:", but precious info
about help and reverse dependencies was lost too.

Revive it now.

"defined at" is contained in menu_get_ext_help(), so I made sure
to not display it twice.

Fixes: 68fd110b3e7e ("kconfig: qconf: remove redundant help in the info view")
Reported-by: Maxim Levitsky <mlevitsk@redhat.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

kconfig: qconf: fix incomplete type 'struct gstr' warning

"make HOSTCXX=clang++ xconfig" reports the following:

  HOSTCXX scripts/kconfig/qconf.o
In file included from scripts/kconfig/qconf.cc:23:
In file included from scripts/kconfig/lkc.h:15:
scripts/kconfig/lkc_proto.h:26:13: warning: 'get_relations_str' has C-linkage specified, but returns incomplete type 'struct gstr' which could be incompatible with C [-Wreturn-type-c-linkage]
struct gstr get_relations_str(struct symbol **sym_arr, struct list_head *head);
            ^

Currently, get_relations_str() is declared before the struct gstr
definition.

Move all declarations of menu.c functions below.

BTW, some are declared in lkc.h and some in lkc_proto.h, but the
difference is unclear. I guess some refactoring is needed.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Boris Kolpackov <boris@codesynthesis.com>

Merge branch 'akpm' (patches from Andrew)

Merge fixes from Andrew Morton:
 "15 patches.

  Subsystems affected by this patch series: mailmap, mm/hotfixes,
  mm/thp, mm/memory-hotplug, misc, kcsan"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  kcsan: kconfig: move to menu 'Generic Kernel Debugging Instruments'
  fs/fs-writeback.c: adjust dirtytime_interval_handler definition to match prototype
  stackleak: let stack_erasing_sysctl take a kernel pointer buffer
  ftrace: let ftrace_enable_sysctl take a kernel pointer buffer
  mm/memory_hotplug: drain per-cpu pages again during memory offline
  selftests/vm: fix display of page size in map_hugetlb
  mm/thp: fix __split_huge_pmd_locked() for migration PMD
  kprobes: fix kill kprobe which has been marked as gone
  tmpfs: restore functionality of nr_inodes=0
  mlock: fix unevictable_pgs event counts on THP
  mm: fix check_move_unevictable_pages() on THP
  mm: migration of hugetlbfs page skip memcg
  ksm: reinstate memcg charge on copied pages
  mailmap: add older email addresses for Kees Cook

Merge branch 'i2c/for-current' of git://git./linux/kernel/git/wsa/linux

Pull i2c fixes from Wolfram Sang:
 "Another bunch of fixes for I2C.

  Jean's i801 patch is a cleanup on top of Volker's i801 patch, but it
  will make dependency handling much easier if those two go together"

* 'i2c/for-current' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux:
  i2c: mxs: use MXS_DMA_CTRL_WAIT4END instead of DMA_CTRL_ACK
  i2c: mediatek: Send i2c master code at more than 1MHz
  i2c: mediatek: Fix generic definitions for bus frequency
  i2c: core: Call i2c_acpi_install_space_handler() before i2c_acpi_register_devices()
  i2c: i801: Simplify the suspend callback
  i2c: i801: Fix resume bug
  i2c: aspeed: Mask IRQ status to relevant bits

RISC-V: Resurrect the MMIO timer implementation for M-mode systems

The K210 doesn't implement rdtime in M-mode, and since that's where Linux runs
in the NOMMU systems that means we can't use rdtime.  The K210 is the only
system that anyone is currently running NOMMU or M-mode on, so here we're just
inlining the timer read directly.

This also adds the CLINT driver as an !MMU dependency, as it's currently the
only timer driver availiable for these systems and without it we get a build
failure for some configurations.

Tested-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>

riscv: Fix Kendryte K210 device tree

The Kendryte K210 SoC CLINT is compatible with Sifive clint v0
(sifive,clint0). Fix the Kendryte K210 device tree clint entry to be
inline with the sifive timer definition documented in
Documentation/devicetree/bindings/timer/sifive,clint.yaml.
The device tree clint entry is renamed similarly to u-boot device tree
definition to improve compatibility with u-boot defined device tree.
To ensure correct initialization, the interrup-cells attribute is added
and the interrupt-extended attribute definition fixed.

This fixes boot failures with Kendryte K210 SoC boards.

Note that the clock referenced is kept as K210_CLK_ACLK, which does not
necessarilly match the clint MTIME increment rate. This however does not
seem to cause any problem for now.

Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>

riscv: Add sfence.vma after early page table changes

This invalidates local TLB after modifying the page tables during early init as
it's too early to handle suprious faults as we otherwise do.

Fixes: f2c17aabc917 ("RISC-V: Implement compile-time fixed mappings")
Reported-by: Syven Wang <syven.wang@sifive.com>
Signed-off-by: Syven Wang <syven.wang@sifive.com>
Signed-off-by: Greentime Hu <greentime.hu@sifive.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
[Palmer: Cleaned up the commit text]
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>

kcsan: kconfig: move to menu 'Generic Kernel Debugging Instruments'

This moves the KCSAN kconfig items under menu 'Generic Kernel Debugging
Instruments' where UBSAN resides.

Signed-off-by: Changbin Du <changbin.du@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tested-by: Randy Dunlap <rdunlap@infradead.org>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Marco Elver <elver@google.com>
Link: https://lkml.kernel.org/r/20200904152224.5570-1-changbin.du@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/fs-writeback.c: adjust dirtytime_interval_handler definition to match prototype

Commit 32927393dc1c ("sysctl: pass kernel pointers to ->proc_handler")
changed ctl_table.proc_handler to take a kernel pointer.  Adjust the
definition of dirtytime_interval_handler to match its prototype in
linux/writeback.h which fixes the following sparse error/warning:

fs/fs-writeback.c:2189:50: warning: incorrect type in argument 3 (different address spaces)
fs/fs-writeback.c:2189:50:    expected void *
fs/fs-writeback.c:2189:50:    got void [noderef] __user *buffer
fs/fs-writeback.c:2184:5: error: symbol 'dirtytime_interval_handler' redeclared with different type (incompatible argument 3 (different address spaces)):
fs/fs-writeback.c:2184:5:    int extern [addressable] [signed] [toplevel] dirtytime_interval_handler( ... )
fs/fs-writeback.c: note: in included file:
./include/linux/writeback.h:374:5: note: previously declared as:
./include/linux/writeback.h:374:5:    int extern [addressable] [signed] [toplevel] dirtytime_interval_handler( ... )

Fixes: 32927393dc1c ("sysctl: pass kernel pointers to ->proc_handler")
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Link: https://lkml.kernel.org/r/20200907093140.13434-1-tklauser@distanz.ch
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

stackleak: let stack_erasing_sysctl take a kernel pointer buffer

Commit 32927393dc1c ("sysctl: pass kernel pointers to ->proc_handler")
changed ctl_table.proc_handler to take a kernel pointer.  Adjust the
signature of stack_erasing_sysctl to match ctl_table.proc_handler which
fixes the following sparse warning:

kernel/stackleak.c:31:50: warning: incorrect type in argument 3 (different address spaces)
kernel/stackleak.c:31:50:    expected void *
kernel/stackleak.c:31:50:    got void [noderef] __user *buffer

Fixes: 32927393dc1c ("sysctl: pass kernel pointers to ->proc_handler")
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Link: https://lkml.kernel.org/r/20200907093253.13656-1-tklauser@distanz.ch
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

ftrace: let ftrace_enable_sysctl take a kernel pointer buffer

Commit 32927393dc1c ("sysctl: pass kernel pointers to ->proc_handler")
changed ctl_table.proc_handler to take a kernel pointer.  Adjust the
signature of ftrace_enable_sysctl to match ctl_table.proc_handler which
fixes the following sparse warning:

kernel/trace/ftrace.c:7544:43: warning: incorrect type in argument 3 (different address spaces)
kernel/trace/ftrace.c:7544:43:    expected void *
kernel/trace/ftrace.c:7544:43:    got void [noderef] __user *buffer

Fixes: 32927393dc1c ("sysctl: pass kernel pointers to ->proc_handler")
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Link: https://lkml.kernel.org/r/20200907093207.13540-1-tklauser@distanz.ch
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/memory_hotplug: drain per-cpu pages again during memory offline

There is a race during page offline that can lead to infinite loop:
a page never ends up on a buddy list and __offline_pages() keeps
retrying infinitely or until a termination signal is received.

Thread#1 - a new process:

load_elf_binary
 begin_new_exec
  exec_mmap
   mmput
    exit_mmap
     tlb_finish_mmu
      tlb_flush_mmu
       release_pages
        free_unref_page_list
         free_unref_page_prepare
          set_pcppage_migratetype(page, migratetype);
             // Set page->index migration type below  MIGRATE_PCPTYPES

Thread#2 - hot-removes memory
__offline_pages
  start_isolate_page_range
    set_migratetype_isolate
      set_pageblock_migratetype(page, MIGRATE_ISOLATE);
        Set migration type to MIGRATE_ISOLATE-> set
        drain_all_pages(zone);
             // drain per-cpu page lists to buddy allocator.

Thread#1 - continue
         free_unref_page_commit
           migratetype = get_pcppage_migratetype(page);
              // get old migration type
           list_add(&page->lru, &pcp->lists[migratetype]);
              // add new page to already drained pcp list

Thread#2
Never drains pcp again, and therefore gets stuck in the loop.

The fix is to try to drain per-cpu lists again after
check_pages_isolated_cb() fails.

Fixes: c52e75935f8d ("mm: remove extra drain pages on pcp list")
Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: David Rientjes <rientjes@google.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: <stable@vger.kernel.org>
Link: https://lkml.kernel.org/r/20200903140032.380431-1-pasha.tatashin@soleen.com
Link: https://lkml.kernel.org/r/20200904151448.100489-2-pasha.tatashin@soleen.com
Link: http://lkml.kernel.org/r/20200904070235.GA15277@dhcp22.suse.cz
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

selftests/vm: fix display of page size in map_hugetlb

The displayed size is in bytes while the text says it is in kB.

Shift it by 10 to really display kBytes.

Fixes: fa7b9a805c79 ("tools/selftest/vm: allow choosing mem size and page size in map_hugetlb")
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: <stable@vger.kernel.org>
Link: https://lkml.kernel.org/r/e27481224564a93d14106e750de31189deaa8bc8.1598861977.git.christophe.leroy@csgroup.eu
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/thp: fix __split_huge_pmd_locked() for migration PMD

A migrating transparent huge page has to already be unmapped.  Otherwise,
the page could be modified while it is being copied to a new page and data
could be lost.  The function __split_huge_pmd() checks for a PMD migration
entry before calling __split_huge_pmd_locked() leading one to think that
__split_huge_pmd_locked() can handle splitting a migrating PMD.

However, the code always increments the page->_mapcount and adjusts the
memory control group accounting assuming the page is mapped.

Also, if the PMD entry is a migration PMD entry, the call to
is_huge_zero_pmd(*pmd) is incorrect because it calls pmd_pfn(pmd) instead
of migration_entry_to_pfn(pmd_to_swp_entry(pmd)).  Fix these problems by
checking for a PMD migration entry.

Fixes: 84c3fc4e9c56 ("mm: thp: check pmd migration entry in common path")
Signed-off-by: Ralph Campbell <rcampbell@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Bharata B Rao <bharata@linux.ibm.com>
Cc: Ben Skeggs <bskeggs@redhat.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: <stable@vger.kernel.org> [4.14+]
Link: https://lkml.kernel.org/r/20200903183140.19055-1-rcampbell@nvidia.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kprobes: fix kill kprobe which has been marked as gone

If a kprobe is marked as gone, we should not kill it again.  Otherwise, we
can disarm the kprobe more than once.  In that case, the statistics of
kprobe_ftrace_enabled can unbalance which can lead to that kprobe do not
work.

Fixes: e8386a0cb22f ("kprobes: support probing module __exit function")
Co-developed-by: Chengming Zhou <zhouchengming@bytedance.com>
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: "Naveen N . Rao" <naveen.n.rao@linux.ibm.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Song Liu <songliubraving@fb.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: <stable@vger.kernel.org>
Link: https://lkml.kernel.org/r/20200822030055.32383-1-songmuchun@bytedance.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

tmpfs: restore functionality of nr_inodes=0

Commit e809d5f0b5c9 ("tmpfs: per-superblock i_ino support") made changes
to shmem_reserve_inode() in mm/shmem.c, however the original test for
(sbinfo->max_inodes) got dropped.  This causes mounting tmpfs with option
nr_inodes=0 to fail:

  # mount -ttmpfs -onr_inodes=0 none /ext0
  mount: /ext0: mount(2) system call failed: Cannot allocate memory.

This patch restores the nr_inodes=0 functionality.

Fixes: e809d5f0b5c9 ("tmpfs: per-superblock i_ino support")
Signed-off-by: Byron Stanoszek <gandalf@winds.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Hugh Dickins <hughd@google.com>
Acked-by: Chris Down <chris@chrisdown.name>
Link: https://lkml.kernel.org/r/20200902035715.16414-1-gandalf@winds.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mlock: fix unevictable_pgs event counts on THP

5.8 commit 5d91f31faf8e ("mm: swap: fix vmstats for huge page") has
established that vm_events should count every subpage of a THP, including
unevictable_pgs_culled and unevictable_pgs_rescued; but
lru_cache_add_inactive_or_unevictable() was not doing so for
unevictable_pgs_mlocked, and mm/mlock.c was not doing so for
unevictable_pgs mlocked, munlocked, cleared and stranded.

Fix them; but THPs don't go the pagevec way in mlock.c, so no fixes needed
on that path.

Fixes: 5d91f31faf8e ("mm: swap: fix vmstats for huge page")
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Yang Shi <shy828301@gmail.com>
Cc: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Qian Cai <cai@lca.pw>
Link: http://lkml.kernel.org/r/alpine.LSU.2.11.2008301408230.5954@eggly.anvils
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: fix check_move_unevictable_pages() on THP

check_move_unevictable_pages() is used in making unevictable shmem pages
evictable: by shmem_unlock_mapping(), drm_gem_check_release_pagevec() and
i915/gem check_release_pagevec().  Those may pass down subpages of a huge
page, when /sys/kernel/mm/transparent_hugepage/shmem_enabled is "force".

That does not crash or warn at present, but the accounting of vmstats
unevictable_pgs_scanned and unevictable_pgs_rescued is inconsistent:
scanned being incremented on each subpage, rescued only on the head (since
tails already appear evictable once the head has been updated).

5.8 commit 5d91f31faf8e ("mm: swap: fix vmstats for huge page") has
established that vm_events in general (and unevictable_pgs_rescued in
particular) should count every subpage: so follow that precedent here.

Do this in such a way that if mem_cgroup_page_lruvec() is made stricter
(to check page->mem_cgroup is always set), no problem: skip the tails
before calling it, and add thp_nr_pages() to vmstats on the head.

Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Yang Shi <shy828301@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Qian Cai <cai@lca.pw>
Link: http://lkml.kernel.org/r/alpine.LSU.2.11.2008301405000.5954@eggly.anvils
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: migration of hugetlbfs page skip memcg

hugetlbfs pages do not participate in memcg: so although they do find most
of migrate_page_states() useful, it would be better if they did not call
into mem_cgroup_migrate() - where Qian Cai reported that LTP's
move_pages12 triggers the warning in Alex Shi's prospective commit
"mm/memcg: warning on !memcg after readahead page charged".

Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Johannes Weiner <hannes@cmpxch.org>
Cc: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Qian Cai <cai@lca.pw>
Link: http://lkml.kernel.org/r/alpine.LSU.2.11.2008301359460.5954@eggly.anvils
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>